Note: Descriptions are shown in the official language in which they were submitted.
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[0001] METHOD FOR IMPLEMENTING FAST-DYNAMIC CHANNEL
ALLOCATION RADIO RESOURCE MANAGEMENT PROCEDURES
[0002] FIELD OF THE INVENTION
[0003] The present invention relates generally to radio resource
management in wireless communication systems, and more particularly to
implementations of fast dynamic channel allocation (F-DCA) radio resource
management (RRM) procedures.
[0004] BACKGROUND OF THE INVENTION
[0005] In wireless communication systems, RRM is generally responsible for
utilizing the air interface resources. RRM is used to guarantee quality of
service (QoS), to provide efficient use of the radio resources, and to
increase
system capacity. RRM consists of admission control, handover, power control,
and congestion control functionalities. Admission control can be divided into
user admission control and call admission control (CAC). User admission
control accepts or rejects the radio resource c~ntrol (RRC) connection
requested by a wireless transmit/receive unit (WTRU). Call admission control
accepts or rejects a request to establish or modify a radio access bearer
(RAB)
in the radio access network (RAN). Call admission control is located in the
controlling radio network controller (C-RNC).
[0006] There are two dynamic channel allocation (DCA) functions, slow DCA
and fast DCA (S-DCA, F-DCA). The S-DCA allocates the radio resources to
cells while the F-DCA allocates the radio resources to bearer service. The F-
DCA call admission control functions are responsible for efficiently
allocating
or changing the allocations of physical resources. When a request for physical
resources is received, the call admission control will accept or reject the
request based on the availability of physical resources and interference level
in the cell. The request can be accepted only if both uplink and downlink call
admission control admit it. Otherwise, the request is rejected.
[0007] In order to guarantee the QoS and minimize the interference, a
certain F-DCA call admission control algorithm is currently implemented. But
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the previous implementation of the F-DCA call admission control algorithm
has several limitations. One limitation is that it is difficult to be reused
by
other RRM functions since the main interface function is large and the inputs
to the code allocation function (which forms the core function of the F-DCA
call admission control algorithm) are dependent on the signal message. A
second limitation is that the past implementation of the F-DCA CAC
algorithm is generally only suitable for real time (RT) service.
[0008] Two F-DCA functions, which could be in the form of algorithms, are
executed by RRM at steady state operation: one for background interference
reduction and one for an escape mechanism.
[0009] The F-DCA background interference reduction procedure is used to
keep WTRU and system resource usage at a reasonable level at all times by
reassigning radio resources (timeslots and codes) to an existing radio bearer.
The F-DCA background interference reduction procedure is triggered by RRM
periodically. The period to trigger the background interference reduction
procedure is a design parameter; in a preferred embodiment of the present
invention, the period is two seconds. It has relatively low priority among the
three F-DCA algorithms.
[0010] The F-DCA escape mechanism is used to solve a link problem of a
user. It is used as an escape mechanism for a specific user (or part of user
services) or a base station that experiences high interference or that cannot
satisfy ~oS by reassigning the radio resources to an existing r adio bear er .
The
F-DCA escape mechanism runs in a cell for all WTRUs in steady state with
real time (RT) services. It does not apply to non-real time (NRT) services.
[0011] Only one F-DCA function is preferably run at a given time in a C-
RNC, because the output of one function may affect the decision of another
function. If more than one of these functions are triggered at exactly the
same
time, the priority of these functions is such that the escape procedure runs
first, call admission control runs second, and the background interference
reduction procedure runs last.
[0012] Handover is used to switch a radio link from one cell to another
without interruption of the call in order to maintain the required QoS. The
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radio link addition procedure is used to establish physical resources for a
new
radio link in a Node B for which a WTRU already has a communication
context when a handover is taking place.
[0013] For time division duplex (TDD) mode, the radio link setup procedure
is used to establish the necessary radio resources for a new radio link
related
to real time (RT) or non-real time (NRT) services. After the radio link is set
up, the radio link reconfiguration procedure is used to add, modify, or delete
any physical resources for this existing radio link. The F-DCA CAC algorithm
is invoked upon receiving the request messages.
[0014] It is desirable to provide an optimized implementation of the F-DCA
CAC algorithm which is suitable for RT and NRT services, and which
overcomes the disadvantages of the known algorithms. It is also desirable to
provide an improved escape mechanism and an implementation of the
background interference reduction procedure, both of which satisfy the
foregoing requirements. It is further desirable to provide an optimized
implementation of the F-DCA CAC algorithm for radio link addition and radio
link reconfiguration, which are suitable for RT and NRT sex°vice, and
whieh
overcome the disadvantages of the known algorithms.
[0015] SUMMARY OF THE INVENTION
[0016] The present invention improves and optimizes the known F-DCA
algorithm implementations by modularizing/categorizing the functionality of
the F-DCA algorithms and making the inputs to the core channel allocation
function of these algorithms independent of signal messages. More
specifically, certain functions in the previous implementation of the F-DCA
CAC algorithm that are signal-dependent are altered to become signal-
independent by the present invention, such that the altered functions are
reusable in the implementation of the escape mechanism. The invention is
described in the context of layer 3 in TDD scenario, but is applicable without
limitation to other modes of transmission as well.
[0017] The ongoing development of third generation wireless
telecommunication systems requires new and efficient radio resource
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management. The present invention provides an optimization to the
implementations of the F-DCA algorithms in RRM. The inventive method
modularizes and modifies the implementation of F-DCA algorithms into three
processes: pre-code allocation, code allocation, and post-code allocation. The
functions in both the pre-code allocation process and the post-code allocation
process are signal-dependent, while the functions in code allocation process
are signal-independent. The pre-code allocation process is used to describe
how and where to retrieve the information from the input message and
databases, and how to prepare the required inputs for the code allocation
process. The post-code allocation process is used to determine what
information should be stored in the databases, and what information should
be provided to the output message. The modularized functions of the present
invention can be reused by other RRM algorithms in both RT service and NRT
service.
[0018] The present invention provides an implementation of the F-DCA CAC
algorithm for radio link setup procedure in RRM. A method of optimizing a F-
DCA CAC algorithm in a wireless communication system includes a pre-code
allocation process, a signal-independent code allocation process, and a post-
code allocation process. The pre-code allocation process includes receiving
and
processing a request message and obtaining system measurements and
information from a centralized database. The code allocation process begins by
checking the availability of codes in the cell and generating timeslot
sequences
for the available timeslots. A code set is assigned to the available timeslots
in
a timeslot sequence, wherein a successful assignment is a solution. The
interference signal code power (ISCP) is calculated for each solution and the
solution having the lowest weighted ISCP is selected as an optimal solution.
The post-code allocation process includes storing allocation information in a
centralized database and creating a response message.
[0019] A method for a F-DCA CAC in a wireless communication system
begins by receiving and processing a request message to initiate the CAC
function. Node B measurements, a list of available timeslots, and a list of
code
sets are retrieved from a centralized database. A set of codes is allocated to
the
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available timeslots and the allocation information is stored in the
centralized
database. A response message is sent with the results of the code allocation
process.
[0020] The present invention provides a method for implementing the F-DCA
escape mechanism in RRM, which increases system efficiency by functioning
as follows. The F-DCA escape mechanism is triggered by RRM for a specific
uplink or downlink coded composite transport channel (CCTrCH) of a WTRU
when one of the following three conditions is met:
[0021] 1) The downlink (DL) timeslot ISCP measured by a WTRU is
greater than a threshold.
[0022] 2) The uplink (UL) timeslot ISCP measured by a Node B is greater
than a threshold. These two thresholds are design parameters, and can be the
same value or can be different values.
[0023] 3) The Node B reaches the maximum allowed transmitted power.
[0024] A method of implementing a F-DCA escape procedure in a wireless
communication system includes a pre-code allocation procedure, a signal-
independent Bode allocation procedure, and a post-code allocation procedure.
The pre-code allocation procedure receives a trigger signal, obtains WTRU
measurements and Node B measurements from an RRC shared cell database,
obtains cell configuration information and WTRU information from a
centralized database, determines the candidate CCTrCH to be reassigned, and
determines the candidate code set to be reassigned. The code allocation
procedure checks the code availability in the cell, checks the transmitted
power of the candidate timeslot, checks if the ISCP of other timeslots is
lower
than that of the candidate timeslot, generates timeslot sequences for the
available timeslots, assigns the candidate code set to the available timeslots
in
a timeslot sequence, wherein a successful assignment is a solution; calculates
an ISCP for each solution; and selects the solution having the lowest weighted
ISCP as an optimal solution. The post-code allocation procedure stores the
reallocation information in the centralized database and creates a physical
channel reconfiguration request message.
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[0025] A method of implementing a F-DCA escape mechanism in a wireless
communication system begins by receiving and processing a trigger signal.
WTRU and Node B measurements are retrieved from a centralized database
and physical resources to be reassigned are determined. A code set is
allocated
to the available timeslots and the allocation information is stored in the
centralized database. A physical channel reconfiguration request message is
sent, containing the new allocation information for this WTRU.
[0026] The present invention provides a method for implementing the F-DCA
background interference reduction procedure in RRM.. A method of
implementing a F-DCA background interference reduction procedure in a
wireless communication system includes a pre-code allocation procedure, a
signal-independent code allocation procedure, and a post-code allocation
procedure. The pre-code allocation procedure receives a background timer
trigger signal; obtains both WTRU and Node B measurements from an RRC
shared cell database; obtains both cell and WTRU information from a
centralized database; determines the candidate timeslots (one for the uplink
direction and one for the downlink direction) to be reassigned; retrieves a
list
of the available timeslots to be used for reassignment from a centralized
database; and determines the candidate code sets to be reassigned. The code
allocation procedure checks the availability of a Bode set in the cell; checks
the
transmission power of a candidate timeslot; generates timeslot sequences for
the available timeslots; assigns a code set to the available timeslots in a
timeslot sequence, wherein a successful assignment is a solution; calculates
an
ISCP for each solution; and selects the solution having the lowest weighted
ISCP as an optimal solution. The post-code allocation procedure stores the
reallocation information in the centralized database and creates a physical
channel reconfiguration request message.
[0027] A method of implementing a F-DCA background interference
reduction procedure in a wireless communication system includes a pre-code
allocation process, a signal-independent code allocation process, and a post-
code allocation process. The pre-code allocation process begins by receiving a
timer trigger signal. System measurements are retrieved from a centralized
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database. The physical resources to be reassigned are determined based on a
figure of merit. The code allocation process begins by checking the
availability
of a code set in the cell and generating timeslot sequences for the available
timeslots. A code set is allocated to the available timeslots in a timeslot
sequence, wherein a successful assignment is a solution. The ISCP is
calculated for each solution and the solution having the lowest weighted ISCP
is selected as an optimal solution. The reallocation information is stored in
the
centralized database. A physical channel reconfiguration request message is
sent, containing the allocation information.
[0028] The present invention provides an implementation of the F-DCA CAC
algorithm for radio link addition procedure in RRM. A method of
implementing F-DCA CAC algorithm for radio link addition in a wireless
communication system includes a pre-code allocation process, a signal-
independent code allocation process, and a post-code allocation process. The
pre-code allocation process includes receiving and processing a radio link
addition request message, and retrieving system information from a
centralized database. The code allocation process includes checking the
availability of a code set in the cell; generating timeslot sequences;
assigning a
code set to the available timeslots in a timeslot sequence, wherein a
successful
assignment is a solution; calculating ISCP for each solution; and selecting
the
solution having the lowest weighted ISCP as an optimal solution. The post-
code allocation process includes storing allocation information in the
centralized database and creating a radio link addition response message.
[0029] A method of implementing F-DCA CAC algorithm for radio link
addition in a wireless communication system begins by receiving a radio link
addition request message to initiate the CAC function. The request message is
processed and a list of available timeslots and a list of code sets are
retrieved
from a centralized database. The code sets are allocated to the available
timeslots in the new cell, and the allocation information is stored in the
centralized database. A radio link addition response message is then sent with
the results of the code allocation process.
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[0030] The present invention provides an implementation of the F-DCA CAC
algorithm for radio link reconfiguration procedure in RRM. A method of
implementing F-DCA CAC for radio link reconfiguration in a wireless
communication system includes a pre-code allocation process, a signal-
independent code allocation process, and a post-code allocation process. The
pre-code allocation process includes receiving and processing a request
message, and retrieving system information from a centralized database. The
code allocation process includes checking the availability of a code set in
the
cell; generating timeslot sequences; assigning a code set to the available
timeslots in a timeslot sequence, wherein a successful assignment is a
solution; calculating the ISCP for each solution; and selecting the solution
having the lowest weighted ISCP as an optimal solution. The post-code
allocation process includes storing allocation information in a centralized
database and creating a response message.
[0031] A method for F-DCA CAC for radio link reconfiguration in a wireless
communication system begins by receiving a request message to initiate the
CAC function. The request message is processed and a list of available
timeslots and a list of code sets is retrieved from a centralized database.
The
code sets are allocated to the available timeslots and the allocation
information is stored in the centralized database. A response message with
the results of the code allocation process is then sent.
[0032] BRIEF DESCRIPTION OF THE DRAWINGS
[0033] A more detailed understanding of the invention may be had from the
following description of a preferred embodiment, given by way of example, and
to be understood in conjunction with the accompanying drawings wherein:
[0034] Figure 1 is an overview of the F-DCA CAC algorithm for radio link
setup;
[0035] Figures 2a-2c are flowcharts of the F-DCA CAC algorithm for radio
link setup shown in Figure 1;
[0036] Figures 3a and 3b are flowcharts for the channel allocation function
for the F-DCA CAC algorithm shown in Figure 2;
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[0037] Figure 4 is an overview of a F-DCA escape procedure in accordance
with the present invention;
[0038] Figures 5a and 5b show a flowchart of the F-DCA escape procedure
shown in Figure 4;
[0039] Figure 6 shows the first part a flowchart for the channel allocation
function for the F-DCA escape procedure shown in Figures 5a and 5b;
[0040] Figure 7 is an overview of a F-DCA background interference reduction
procedure in accordance with the present invention;
[0041] Figures 8a and 8b show flowcharts of the F-DCA background
interference reduction procedure shown in Figure 7;
[0042] Figure 9 is an overview of a F-DCA CAC procedure for radio link
addition in accordance with the present invention;
[0043] Figures l0a-lOc are flowcharts of the F-DCA CAC procedure shown in
Figure 9;
[0044] Figure 11 is an overview of a F-DCA CAC procedure for radio link
reconfiguration in accordance with the present invention;
[0045] Figure 12 is a flowchart of the F-DCA CAC procedure for radio link
reconfiguration shown in Figure 11; and
[0046] Figures 13a-13c are flowcharts of a physical channel allocation
procedure of the F-DCA CAC procedure for radio link reconfiguration shown
in Figure 12.
[0047] DETAILED DESCRIPTION OF PREFERRED EMBODIMENT
[0048] Call Admission Control for Radio Link Setup
[0049] An overview 100 of the F-DCA CAC algorithm for radio link setup
procedure 102 is shown in Figure 1. The main function of the F-DCA CAC
algorithm 102 consists of three parts: the pre-code allocation process 104,
the
code allocation process 106, and the post-code allocation process 108. The pre-
code allocation process 104 reads WTRU measurements from radio link setup
request message 110 and Node B measurements from the RRC shared cell
database 112 and prepares the inputs (a list of available timeslots from the
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RRM cell database 116 and a list of code sets from the operations and
maintenance (OAM) RRM table database 114) for the code allocation.
[0050] The code allocation process 106 checks the code availability in the
cell, generates timeslot sequences, finds the optimal solution for the code
set
(assigns the codes in the code set to the available timeslots), and allocates
the
channelized codes from the code vectors in a RRM cell database 116. The post-
code allocation process 108 is responsible for creating a WTRU entity in a
RRM WTRU database 118, recording the allocated physical channels in the
RRM WTRU database 118, recording the physical channel parameters and
power control information in the radio link setup response message 120.
[0051] In addition to the data exchanges between the processes and the
databases, there are data exchanges occurring directly between the processes.
The WTRU measurements, the Node B measurements, a list of the available
timeslots in the cell, a list of code sets for the specific data rate, and
WTRU
capability information are passed from the pre-code allocation process 104 to
the code allocation process 106. The physical channel information (a list of
timeslots and channelized codes in each timeslot) are passed from the code
allocation process 106 to the post-code allocation process 108.
[0052] In the present invention, the functions of the F-DCA CAC algorithm
for radio link setup procedure 102 are modularized into two groups of
functions: signal-dependent functions whose inputs are parts of signal
messages and signal-independent functions whose inputs are independent of
signal messages. The purpose of separating the signal-dependent functions
and the signal-independent functions is to increase the reusability of the
signal-independent functions. The functions of both the pre-code allocation
process 104 and the post-code allocation process 108 are signal-dependent
functions. In contrast, the functions of the code allocation process 106 are
signal-independent functions. It is to be noted that the functions of the code
allocation process 106 can be reused by other procedures in other RRM
function implementations, such as handover, F-DCA escape algorithm, and F-
DCA background interference reduction algorithm.
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[0053] The flowcharts for functions of the F-DCA CAC algorithm for radio
link setup are shown in Figures 2a-2c and 3a-3b. Figures 2a-2c show the main
interface function 200 of the F-DCA CAC algorithm for radio link (RL) setup.
The function 200 begins by obtaining the RL setup request message (referred
to hereinafter as "request message"; step 202) and extracting parameters from
the request message (step 204). The request message contains coded composite
transport channel (CCTrCH) information, dedicated channel (DCH)
information, RL information with or without WTRU measurements, and
WTRU capability information. The parameters extracted from the request
message include information such as the WTRU identification, the cell
identification, the RL identification, and WTRU capability information (the
maximum number of physical channels per timeslot and the maximum
number of timeslots per frame).
[0054] The entry identification of the RRM cell database is obtained (step
206). Next, a determination is made whether the WTRU measurements, which
include the downlink interference signal code power (DL ISCP), are included
in the request message (step 208). If the WTRU measurements are not
included in the request message, then a check is made to determine whether
all of the DCHs are non-real time (NRT; steps 210 and 212). If all the DCHs
are not NRT, then a status flag is set to indicate a failure condition (step
214)
and the function terminates (step 216). The failure condition means that there
are no physical resources available for the WTRU. It is noted that all DCHs
not being NRT alone is not a failure condition. The failure condition is
reached
when there are no WTRU measurements and all the DCHs are not NRT.
[0055] If all the DCHs are NRT (step 212), then the low rate temporary
DCHs are allocated for the present CCTrCH (step 218). After the channels are
allocated, a determination is made whether the resource allocation was
successful (step 220). If the resource allocation was not successful, then the
status flag is set to indicate a failure condition (step 214) and the function
terminates (step 216). If the resource allocation was successful (step 220),
then
a WTRU entity is created and the WTRU information and the physical
channel parameters are recorded in the RRM WTRU database (step 222). The
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information recorded to a WTRU entity includes the WTRU identification, the
transaction identification, the uplink (UL) WTRU capability information, the
DL WTRU capability information, and the RL information. The UL WTRU
capability information includes the maximum number of timeslots per frame
and the maximum number of UL physical channels per timeslot. The DL
WTRU capability information includes the maximum number of timeslots per
frame and the maximum number of DL physical channels per frame. The RL
information includes the RL identification, the cell identification, the UL
CCTrCH information, and the DL CCTrCH information. The CCTrCH
information includes the CCTrCH identification, the CCTrCH status, the
CCTrCH signal to interference ratio (SIR) target, the guaranteed data rate,
the allowed data rate, and the dedicated physical channel (DPCH)
information. The DPCH information includes a list of timeslots, the midamble
shift and burst type, the transport format code indicator (TFCI) presence, and
the code information. The code information includes the channelized code, the
code usage status, the DPCH identification, and the code SIR target.
[0056] Next, the physical channel information and power control information
is placed into a RL setup response message (step 224), the status flag is set
to
indicate a success condition (step 226), and the function terminates (step
216).
The physical channel information includes a list of timeslots and the
channelized codes in each timeslot. The timeslot information includes a
repetition period and a repetition length. The power control information
includes the UL target SIR, the maximum UL SIR, the minimum UL SIR, the
initial DL transmission power, the minimum DL transmission power, and the
maximum allowed UL transmission power. In one implementation of the
present invention, a single data structure is used for both the request
message
and the response message since these two messages include a large amount of
common information.
[0057] If the WTRU measurements are available in the request message
(step 208), then the WTRU measurements are retrieved from the request
message and Node B measurements are obtained from the RRC shared cell
database (step 228). The Node B measurements include common
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measurements and dedicated measurements. The Node B common
measurements include the UL ISCP and the DL transmitted carrier power.
The Node B dedicated measurements include the DL transmitted code power.
The first DL CCTrCH is selected (step 230) and the service type for the
selected CCTrCH is obtained (step 232). If the service type is real time (RT;
step 234), the available timeslots in the cell are determined (step 236). If
no
timeslots are available (step 238), the status flag is set to indicate a
failure
condition (step 214) and the function terminates (step 216).
[0058] If there are timeslots available (step 238), then the requested data
rate is calculated (step 240). The code sets for the calculated data rate are
obtained (step 242) and the physical channels (timeslots and codes) for the
present CCTrCH are allocated and the optimal solution is recorded if found
(step 244). The allocation function in step 244 is discussed in greater detail
below in connection with Figures 3a and 3b. If the resource allocation was not
successful (step 246), then the status flag is set to indicate a failure
condition
(step 214) and the function terminates (step 216).
[0059] If the resource allocation was successful (step 246), then a
determination is made whether there are additional CCTrCHs to be examined
(step 248). If there are additional CCTrCHs to be examined, then the next
CCTrCH is selected (step 250) and the function continues at step 232. If there
are no additional CCTrCHs to be examined (step 248), then a determination is
made whether the UL CCTrCHs have been examined (step 252). If the UL
CCTrCHs have not been examined, then the first UL CCTrCH is selected (step
254) and the function continues at step 232. If all of the UL CCTrCHs have
been considered (step 252), then the function continues at step 222, as
described above.
[0060] If the service type is NRT (step 234), the available timeslots in the
cell
are determined (step 25G). If no timeslots are available (step 258), the
status
flag is set to indicate a failure condition (step 214) and the function
terminates
(step 216).
[0061] If there are timeslots available (step 258), then all data rates
suitable
for the NRT service are determined (step 260) and the highest data rate is
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selected (step 262). The code sets for the selected data rate are obtained
(step
264) and the normal temporary DCHs for the present CCTrCH are allocated
and the optimal solution is recorded if found (step 266). It is noted that
steps
244 and 266 are essentially the same; in NRT service, the DCHs are
temporary.
[0062] If the resource allocation was not successful (step 268), then a
determination is made whether there are additional data rates to be examined
(step 270). If there are no other data rates to be examined, then the status
flag
is set to indicate a failure condition (step 214) and the function terminates
(step 216). If there are other data rates to be examined (step 270), then the
next highest data rate is selected (step 272) and the function continues at
step
264. If the resource allocation was successful (step 268), then the function
continues at step 248 as described above.
[0063] It is noted that in connection with steps 230, 252, and 254 that either
direction (DL or UL) can be performed first. As described above, the DL
direction is examined prior to the UL direction. The function 200 will operate
in the same manner if instead the UL was examined prior to the DL.
[0064] The steps 244 and 266 relate to calling the core function of the F-DCA
algorithms to allocate the physical channels. This core function 300 is signal-
independent and is described in connection with Figures 3a and 3b. The
function 300 begins by receiving the code sets and the available timeslots as
inputs (step 302). The first code set is selected (step 304) and a
determination
is made whether the code set is available in the cell (steps 306 and 308). If
the
selected code set is not available in the cell, then a determination is made
whether there are more code sets to be examined (step 310). If there are more
code sets, then the next code set is selected (step 312) and the function
continues with step 306. If there are no more code sets, this indicates a
failure
condition, and a status flag is set to indicate that no solution is available
(step
314) and the function terminates (step 316).
[0065] If the selected code set is available in the cell (step 308), then the
required resource units for the code set in the CCTrCH are calculated (step
318). The timeslot sequences are generated (step 320) and the first timeslot
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sequence is selected (step 322). The link direction, either DL or UL, is then
determined (step 350). If the link direction is DL, then an attempt is made to
assign the current DL code set into the available timeslots in the current
timeslot sequence (step 352). If the link direction is UL (step 350), then an
attempt is made to assign the current UL code set into the available timeslots
in the current timeslot sequence (step 354). In an alternate embodiment of the
present invention (not shown), step 350 can be eliminated and steps 352 and
354 can be combined into a single step, to provide additional optimization.
[0066] After an attempt has been made to assign the current code set to the
available timeslots in the current timeslot sequence (steps 352, 354), a
determination is made whether an assignment solution has been found (step
356), indicating that the code set was successfully assigned to the available
timeslots in the current timeslot sequence. If a solution has been found, then
the ISCP of the solution is determined, and the solution having the lowest
weighted ISCP is considered to be the optimal solution and is recorded (step
358). If no solution was found (step 356), then step 358 is skipped.
[006'7] :L~Text, a determination is made whether there are any additional
timeslot sequences to be considered (step 360). If there are additional
timeslot
sequences, then the next timeslot sequence is selected (step 362) and the
function continues with step 350. If there are no additional timeslot
sequences
(step 360), then a determination is made whether an optimal solution has
been found (step 364). If no optimal solution has been found, then the
function
continues at point C in the calling function (i.e., the function from which
step
350 was entered). If the optimal solution has been found, then the status flag
is set to indicate a successful assignment (step 366) and the function
terminates (step 316).
[0068] In past implementations of the F-DCA CAC algorithm, the functions
352 and 354 are signal-dependent. In the present invention, these two
functions are modified to become signal-independent functions. All related
functions used in these two functions are also modified to become signal-
independent functions. Because the inputs of the functions 352, 354 are
independent of the signal message (such as the input message), the functions
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352, 354 can be used by other RRM procedures. It is noted that the above-
described implementation of the F-DCA CAC algorithm is exemplary and can
be further optimized.
[0069] Esca a
[0070] An overview 400 of the F-DCA escape procedure 402 is shown in
Figure 4. The main function of the F-DCA escape procedure 402 consists of
three parts: the pre-code allocation process 404, the code allocation process
406, and the post-code allocation process 408. The pre-code allocation process
404 is started upon receipt of a measurement trigger signal 410. There are two
measurement trigger signals, a WTRU measurement trigger signal and a
Node B measurement trigger signal. The WTRU measurement trigger signal
contains the WTRU identification and a list of timeslot numbers, while the
Node B measurement trigger signal contains a timeslot number. The escape
procedure begins upon receipt of either the WTRU measurement trigger signal
or the Node B measurement trigger signal.
[00'71] The pre-code allocation process 404 gets Node B measurements and
WTRU measurements from a RRC shared cell database 412, gets cell
configuration information from a RRM cell database 416, obtains WTRU
capability information from a RRM WTRU database 418, determines the
CCTrCH to be reassigned, calculates the WTRU pathloss, determines the
candidate code set to be reassigned, and obtains a list of the available
timeslots. The pre-code allocation process 404 prepares the inputs for the
code
allocation process 406.
[0072] The code allocation process 406 checks the code availability in the
cell, checks the transmission (Tx) power of the candidate timeslot, checks if
the ISCP of other timeslots is lower than that of the candidate timeslot,
generates timeslot sequences for the available timeslots, finds the assignment
solution for the code set in a timeslot sequence (by assigning the candidate
code set to the available timeslots), and selects the solution that has the
lowest weighted ISCP as the optimal solution. The post-code allocation process
408 is responsible for recording the newly allocated physical channels in the
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RRM WTRU database 418 and filling the physical channel information into a
physical channel reconfiguration request message 420.
[0073] In addition to the data exchanges between the processes and the
databases, there are data exchanges occurring directly between the processes.
The WTRU measurements, the Node B measurements, a list of available
timeslots in the cell, a candidate code set, and WTRU capability information
are passed from the pre-code allocation process 404 to the code allocation
process 406. The physical channel information (a list of timeslots and
channelized codes in each timeslot) are passed from the code allocation
process
406 to the post-code allocation process 408.
[0074] In the present invention, the functions of the F-DCA escape algorithm
402 are modularized into two groups of functions: signal-dependent functions
whose inputs are parts of signal messages and signal-independent functions
whose inputs are independent of signal messages. The purpose of separating
the signal-dependent functions and the signal-independent functions is to
increase the reusability of the signal-independent functions. The functions of
both the pre-Bode allocation process 404 and the post-code allocation process
408 are signal-dependent functions. In contrast, the functions of the code
allocation process 406 are signal-independent functions. Therefore, the
reusability of signal-independent functions is higher than that of the signal-
dependent functions. Certain functions, which are inherently signal-
dependent, are converted in the preferred embodiment of the present
invention from being signal-dependent to signal-independent, thereby
increasing the reusability of the converted functions.
[00'75] The flowcharts for functions of the F-DCA escape procedure are
shown in Figures 5a, 5b, and 6. Figures 5a and 5b show flowcharts of the main
escape algorithm 500, which begins by receiving inputs from the trigger
signals (step 502). The entry identification of the RRM cell database is
retrieved from the RRM cell database (step 504). The WTRU measurements
and the Node B measurements are retrieved from the shared cell database
(step 506). The link direction of the timeslots that have a link problem is
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determined (step 508) and the timeslot that has the worst link problem is
located.
[0076] A candidate CCTrCH to be reassigned is determined based on how
the escape mechanism is triggered (step 510). When the escape procedure is
triggered by a too high DL ISCP of a WTRU in a timeslot, the CCTrCH of the
WTRU in this timeslot is the candidate to be reassigned. The DL ISCP is
measured by the WTRU, and in this case, the escape procedure is triggered by
the WTRU measurement signal.
[0077] When the escape procedure is triggered by a too high UL ISCP in a
timeslot, the CCTrCH that has the code with the highest value of SIR plus
pathloss is the candidate to be reassigned. When the escape procedure is
triggered by a too high Node B transmitted carrier power, the CCTrCH that
has the code with the highest Node B transmitted code power is the candidate
to be reassigned. The UL ISCP and the Node B transmitted carrier power are
both measured by the Node B, and in both of these cases, the escape procedure
is triggered by the Node B measurement signal.
[0078] If no candidate CCTrCH is found (step 512), then a status flag is set
to indicate a failure condition (step 514) and the procedure terminates (step
516). If a candidate CCTrCH is found (step 512), then the WTRU capability
information is retrieved from the RRM WTRU database (step 518). The
pathloss of the WTRU is calculated (step 520) and a candidate code set to be
reassigned is determined (step 522). The candidate code set is determined
based on if the updated ISCP of the given timeslot is less than the ISCP
threshold, or if the updated timeslot transmitted power is less than the
transmitted power threshold after this set of codes is removed from the
timeslot which has a link problem. In this determination, both the ISCP
threshold and the transmitted power threshold are design parameters. If
there is no code set to be reassigned (step 524), then the status flag is set
to
indicate a failure condition (step 514) and the procedure terminates (step
516).
[0079] If there is a code set to be reassigned (step 524), then the available
timeslots for the codes to be reassigned are retrieved from the centralized
database (step 526). If there are no timeslots available (step 528), then the
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status flag is set to indicate a failure condition (step 514) and the
procedure
terminates (step 516). If there are timeslots available (step 528), then the
physical channels (timeslots and codes) are allocated for the CCTrCH (step
530).
[0080] If the physical channel allocation is not successful (step 532), then
the
status flag is set to indicate a failure condition (step 514) and the
procedure
terminates (step 516). If the resource allocation is successful (step 532),
then
the new physical channel information is recorded in the RRM WTRU database
(step 534). The resource allocation (step 532) is considered to be successful
only if the optimal solution is found. The physical channel information
includes a list of dedicated physical channel timeslot information, a
repetition
period value, and a repetition length value. The dedicated physical channel
timeslot information includes the timeslot number, the midamble shift and
burst type, the TFCI presence, and a list of code information. The code
information includes the channelized code, the code usage status, the DPCH
identification, and the code SIR target.
[0081] The physical channel information is also plaeed into a physical
channel reconfiguration request message (step 536), the status flag is set to
indicate a successful allocation (step 538), and the procedur a terminates
(step
516). The physical channel reconfiguration request message includes the
following information: the WTRU identification, the C-RNC identification, the
radio link identification, the radio resource control transaction
identification,
UL CCTrCH information, and DL CCTrCH information.
[0082] The step 530 relates to calling the core function of the F-DCA escape
procedure to allocate the physical channels. This core function 600 is signal-
independent and is described in connection with Figures 6 and 3b. The
function 600 begins by receiving the code sets, the available timeslots, and
an
F-DCA type indicator as inputs (step 602). The first code set is selected
(step
604) and a determination is made whether the code set is available in the cell
(steps 606 and 608). If the selected code set is not available in the cell
(step
608), then a determination is made whether there are more code sets to be
examined (step 610). If there are more code sets, then the next code set is
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selected (step 612) and the function continues with step 606. If there are no
more code sets (step 610), this indicates a failure condition, and a status
flag is
set to indicate that no solution is available (step 314; Figure 3b) and the
function terminates (step 316; Figure 3b).
[0083] If the selected code set is available in the cell (step 608), then the
F-
DCA type is checked (step 618). The F-DCA type is set based on different RRM
functions such as radio bearer setup ("RBSETUP"), escape mechanism, or
background interference reduction. In the escape procedure, the F-DCA type is
set to "ESCAPE," and can be set at any step before step 530 above. If the F-
DCA type is "ESCAPE," then the transmission power of the candidate timeslot
is checked to determine if it is larger than the minimum required
transmission power (step 620). If the candidate timeslot transmission power is
less than the minimum value (step 622), then the status flag is set to
indicate
that no solution is available (step 314) and the function terminates (step
316;
Figure 3b).
[0084] If the candidate timeslot transmission power is greater than the
minimum value (step 622), then a cheek is made to determine if there are any
timeslots that have a lower ISCP than the timeslot that reports the link
problem (step 624). If there is no other timeslot with a lower ISCP (step
626),
then the status flag is set to indicate that no solution is available (step
314;
Figure 3b) and the function terminates (step 316; Figure 3b).
[0085] If there is another timeslot with a lower ISCP (step 626) or if the F-
DCA type is "RBSETUP" (step 618), then the required resource units for the
code set in the CCTrCH are calculated (step 640). The timeslot sequences are
generated for the available timeslots (step 642) and the first timeslot
sequence
is selected (step 644). The method then continues with step 350, as described
above in connection with Figure 3b. The steps performed if the F-DCA type is
"background" (step 618) are discussed below.
[0086] Background Interference Reduction
[0087] An overview 700 of the F-DCA background interference reduction
procedure 702 is shown in Figure 7. The main function of the F-DCA
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background interference reduction procedure 702 consists of three parts: the
pre-code allocation process 704, the code allocation process 706, and the post-
code allocation process 708. The pre-code allocation process 704 is started
upon receipt of a background timer trigger signal 710. The pre-code allocation
process 704 gets the entry identification of a RRM cell database '116, gets
Node B measurements from a RRC shared cell database 712, determines the
candidate timeslots to be reassigned (one UL timeslot and one DL timeslot),
retrieves a list of the available timeslots to be used for reassignment from
the
RRM cell database 716, determines the candidate code sets to be reassigned in
the candidate timeslot in both directions, obtains WTRU capability
information from a RRM WTRU database 718, and calculates the WTRU
pathloss.
[0088] The code allocation process 706 checks the code availability in the
cell, checks the transmission (Tx) power of the candidate timeslot, finds the
assignment solution for the code set for a timeslot sequence (by assigning the
candidate code set to the available timeslots), and selects the solution that
has
the lowest weighted ISCP as the optimal solution. The post-code allocation
process 708 is responsible for recording the reallocated physical channels in
the RRM WTRU database 718 and filling the physical channel information
into a physical channel reconfiguration request message 720.
[0089] In addition to the data exchanges between the processes and the
databases, there are data exchanges occurring directly between the processes.
The WTRU measurements, the Node B measurements, a list of available
timeslots in the cell, a candidate code set, and WTRU capability information
are passed from the pre-code allocation process 704 to the code allocation
process 706. The physical channel information (a list of timeslots and
channelized codes in each timeslot) are passed from the code allocation
process
706 to the post-code allocation process 708.
[0090] In the present invention, the functions of the F-DCA background
interference reduction procedure 702 are modularized into two groups of
functions: signal-dependent functions whose inputs are parts of signal
messages and signal-independent functions whose inputs are independent of
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signal messages. The purpose of separating the signal-dependent functions
and the signal-independent functions is to increase the reusability of the
signal-independent functions. The functions of both the pre-code allocation
process 704 and the post-code allocation process 708 are signal-dependent
functions. In contrast, the functions of the code allocation process 706 are
signal-independent functions. Therefore, the reusability of signal-independent
functions is higher than that of the signal-dependent functions. Certain
functions which are inherently signal-dependent are converted in the
preferred embodiment of the present invention from being signal-dependent to
signal-independent, thereby increasing the reusability of the converted
functions.
[0091] The flowcharts for functions of the F-DCA background interference
reduction procedure are shown in Figures 8a, 8b, 6, and 3b. Figures 8a and 8b
show a flowchart of the main background interference reduction procedure
800, which begins (step 802) by retrieving the entry identification of the RRM
cell database (step 804). The WTRU measurements and the Node B
measurements are retrieved from the shared cell database (step 806). The
candidate timeslots for reassignment are determined, one UL timeslot and one
DL timeslot, based upon a figure of merit of the timeslots (step 808). The
timeslot with the lowest figure of merit is selected as the candidate for
reassignment. If there are no timeslots to be reassigned (step 810), a status
flag is set to indicate a failure condition (step 812), and the procedure
terminates (step 814). If there are timeslots to be reassigned (step 810),
then
the link direction is set to the downlink (step 816). It is noted that the
order of
evaluation of link direction is arbitrary, and either the UL or the DL can be
evaluated first.
[0092] The available timeslots in the cell for the selected link direction are
retrieved (step 818). If there are no timeslots available (step 820), then the
status flag is set to indicate a failure condition (step 812), and the
procedure
terminates (step 814). If there are available timeslots (step 820), then the
list
of available timeslots is updated to exclude the candidate timeslot (step
822).
The candidate code sets to be reassigned are determined in the candidate
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timeslots based on a figure of merit of the codes (step 824). The code with
the
lowest figure of merit is selected as the candidate for reassignlb.ent. If
there
are no code sets to be reassigned (step 826), then the status flag is set to
indicate a failure condition (step 812), and the procedure terminates (step
814). If there are code sets to be reassigned (step 826), then the WTRU
capability information is retrieved from the WTRU database (step 828).
[0093] The pathloss of the WTRU is calculated (step 830), and the physical
channels for the current CCTrCH are reallocated (step 832). If the channel
reallocation is not successful (step 834), then status flag is set to indicate
a
failure condition (step 812), and the procedure terminates (step 814). If the
channel reallocation is successful (step 834), then a determination is made
whether the link direction is currently UL (step 836). If the link direction
is
currently DL, then the link direction is set to UL (step 838) and the method
continues with step 818.
[0094] If the current link direction is UL (step 836), then a determination is
made whether the UL CCTrCH and the DL CCTrCH to be reassigned belong
to the same WTRU (step 840). If the CCTrCHs to be reassigned belong to
different WTRUs, then a flag is set to indicate that two different WTRUs are
to be reassigned (step 842). If the CCTrCHs belong to the same WTRU (step
840) or if the flag has been set (step 842), then the physical channel
allocation
information is recorded in the RRM WTRU database (step 844). The physical
channel information includes a list of dedicated physical channel timeslot
information, a repetition period value, and a repetition length value. The
dedicated physical channel timeslot information includes the timeslot number,
the midamble shift and burst type, the TFCI presence, and a list of code
information. The code information includes the channelized code, the code
usage status, the DPCH identification, and the code SIR target.
[0095] The physical channel allocation information is also recorded into a
physical channel reconfiguration request message (step 846), the status flag
is
set to indicate "success" (step 848), and the procedure terminates (step 814).
If
the flag indicates that two WTRUs have CCTrCHs being reassigned (step
842), the corresponding physical channel information for two WTRUs is
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recorded (step 844) and two physical channel reconfiguration request
messages are sent (step 846). The physical channel reconfiguration request
message includes the following information: the WTRU identification, the C-
RNC identification, the radio link identification, the radio resource control
transaction identification, UL CCTrCH information, and DL CCTrCH
information.
[0096] Step 832 relates to calling the core function of the F-DCA background
interference reduction procedure to reallocate the physical channels. This
core
function is signal-independent and is described in connection with Figures 6
and 3b. The function 600 operates in the same manner as described above,
with the following additional steps being performed in connection with the
background interference reduction procedure. In the background interference
reduction procedure, the F-DCA type is set to "BACKGROUND," and it can be
set at any step before step 832 above. If the F-DCA type is "BACKGROUND"
(step 618), then the transmission power of the candidate timeslot is checked
to
determine if it is larger than the minimum required transmission power (step
M0). If the candidate timeslot transmission power is less than the minimum
value (step M2), then the status flag is set to indicate that no solution is
available (step 314; Figure 3b) and the function terminates (step 316; Figure
3b). If the transmission power of the candidate timeslot is greater than the
minimum transmission power (step M2), then the procedure continues with
step 640 as described above.
[0097] Call Admission Control for Radio Link Addition
[0098] An overview 900 of a F-DCA CAC procedure for radio link addition
902 is shown in Figure 9. The main function of the F-DCA CAC procedure 902
consists of three parts: a pre-code allocation process 904, a code allocation
process 906, and a post-code allocation process 908. The pre-code allocation
process 904 reads WTRU measurements from a radio link addition request
message 910 (hereinafter "request message"), reads Node B measurements
from a RRC shared cell database 912, and retrieves CCTrCH information,
DCH information, and WTRU capability information from a RRM WTRU
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database 918. The pre-code allocation process 904 also retrieves a list of the
available timeslots in the new cell from a RRM cell database 916, gets the
data rate for the CCTrCH from a RRM WTRU database 918, and gets the code
sets from an OAM RRM table database 914.
[0099] The code allocation process 906 checks the code availability in the
new cell, generates timeslot sequences for the available timeslots, finds the
optimal solution for the code set (assigns the codes in the code sets to the
available timeslots), and allocates the channelized codes from the code
vectors
in the RRM cell database 916. The post-code allocation process 908 is
responsible for updating code vector information in the RRM cell database
916, recording the new radio link information and physical channel
information in the RRM WTRU database 918, and recording CCTrCHs
information, DCHs information, DPCHs information, UL ISCP information,
and power control information in a radio link addition response message 920.
[0100] In addition to the data exchanges between the processes and the
databases, there are data exchanges occurring directly between the processes.
The WTRU measurements, the l~Tode B measurements, a list of the available
timeslots in the cell, a list of code sets for the specific data rate, and
WTRU
capability information are passed from the pre-code allocation process 904 to
the code allocation process 906. The physical channel information (a list of
timeslots and channelized codes in each timeslot) are passed from the code
allocation process 906 to the post-code allocation process 908.
[0101] In the present invention, the functions of the F-DCA CAC procedure
for radio link addition 902 are modularized into two groups of functions:
signal-dependent functions whose inputs are parts of signal messages and
signal-independent functions whose inputs are independent of signal
messages. The purpose of separating the signal-dependent functions and the
signal-independent functions is to increase reusability of the signal-
independent functions. The functions of both the pre-code allocation process
904 and the post-code allocation process 908 are signal-dependent functions.
In contrast, the functions of the code allocation process 906 are signal-
independent functions. Therefore, the reusability of signal-independent
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functions is higher than that of the signal-dependent functions. Certain
functions which are inherently signal-dependent are converted in the
preferred embodiment of the present invention from being signal-dependent to
signal-independent, thereby increasing the reusability of the converted
functions.
[0102] The flowcharts for functions of the F-DCA CAC procedure for radio
link addition are shown in Figures l0a-lOc, which show the main interface
function 1000 for the F-DCA CAC for RL addition procedure. The function
1000 begins by obtaining the RL addition request message (step 1002) and
extracting the WTRU identification, the new radio link identification, and the
new cell identification from the request message (step 1004). The request
message also contains new RL information with or without WTRU
measurements.
[0103] The entry identification of a new cell in the RRM cell database is
obtained (step 1006). The Node B measurements for the new cell are obtained
from the RRC shared cell database and are stored locally in a measurement
data structure (step 1000. The measurement data structure is stored in the F-
DCA CAC function dynamically. It is created after the F-DCA CAC function is
called and deleted when the F-DCA CAC function is exited. The Node B
measurements include common measurements and dedicated measurements.
The Node B common measurements include the UL ISCP information and the
DL tr ansmitted carrier power. The Node B dedicated measurements include
the DL transmitted code power. Then, the old cell identification is retrieved
based on the WTRU ID from the RRM WTRU database; CCTrCHs information
and DCHs information belonging to that WTRU's radio link in the old cell are
retrieved from RRM WTRU database (step 1010).
[0104] Next, a determination is made whether the WTRU measurements,
which include the DL ISCP and the downlink primary common control
physical channel received signal code power (P-CCPCH RSCP), are included in
the request message (step 1012). If the WTRU measurements are not included
in the request message, then the service type is retrieved from the RRM
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WTRU information (step 1014) and a check is made to determine whether all
of the DCHs are NRT (step 1016).
[0105] If all the DCHs are not NRT, then a status flag is set to indicate a
failure condition (step 1018) and the function terminates (step 1020). The
failure condition here means that there is not enough information to process
the function further. It is noted that all the DCHs not being NRT alone is not
a failure condition; the failure condition is reached when there are no WTRU
measurements and all of the DCHs are not NRT. If all of the DCHs are NRT
(step 1016), then the low rate temporary DCHs are allocated for both UL and
DL CCTrCHs (step 1022). After the channels are allocated, a determination is
made whether the resource allocations were successful (step 1024). If the
resource allocations were not successful, then the status flag is set to
indicate
a failure condition (step 1018) and the function terminates (step 1020). If
the
resource allocations were successful, then the new RL information and the
physical channel information are recorded in the RRM WTRU database, and
the code vector information is updated in the RRM cell database (step 1026).
[0106] The recorded information includes the new RL information and the
new RRC transaction identification. The RL information includes the RL
identification, the cell identification, the UL CCTrCH information, and the DL
CCTrCH information. The CCTrCH information includes the CCTrCH
identification, the CCTrCH status, the CCTrCH SIR target, the guaranteed
data rate, the allowed data rate, and the DPCH information. The DPCH
information includes a list of DPCH timeslot information, a repetition period
value, and a repetition length value. The DPCH timeslot information includes
the timeslot number, the midamble shift and burst type, the TFCI presence,
and a list of code information. The code information includes the channelized
code, the code usage status, the DPCH identification, and the code SIR target.
[0107] The updated code vector information includes both UL code vector
information and DL code vector information. The UL code vector information
includes a code identification, a code block indication, and a code usage
status.
The DL code vector information includes a code identification and a code usage
status.
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[0108] If the WTRU measurements are available in the request message
(step 1012), then the WTRU measurements are retrieved from the request
message and are stored locally (step 1032). The first DL CCTrCH is selected
(step 1034) and the WTRU capability information is retrieved from the RRM
WTRU database based on the WTRU identification, the link direction, and the
old cell identification (step 1036). The service type for the selected CCTrCH
is
obtained from the RRM WTRU database (step 1038). If the service type is RT
(step 1040), the available timeslots in the cell are determined (step 1042).
If no
timeslots are available (step 1044), the status flag is set to indicate a
failure
condition (step 1018) and the procedure terminates (step 1020).
[0109] If there are timeslots available in the new cell (step 1044), then the
highest requested data rate for this CCTrCH in the old cell is retrieved from
the RRM WTRU database (step 1046). The code sets for the requested data
rate are obtained (step 1048) and the physical channels (timeslots and codes)
for the present CCTrCH are allocated and the optimal solution is recorded if
found (step 1050). The allocation function in step 1050 was discussed in
greater detail above in connection with Figures 3a and 3b. If the resource
allocation was not successful (step 1052), then the status flag is set to
indicate
a failure condition (step 1018) and the procedure terminates (step 1020).
[0110] If the resource allocation was successful (step 1052), then a
determination is made whether there are additional CCTrCHs in the current
direction (i.e., downlink or uplink) to be examined (step 1054). If there are
additional CCTrCHs to be examined, then the next CCTrCH is selected (step
1056) and the procedure continues at step 1038. If there are no additional
CCTrCHs to be examined (step 1054), then a determination is made whether
the UL CCTrCHs have been examined (step 1058). If the UL CCTrCHs have
not been examined, then the first UL CCTrCH is selected (step 1060) and the
procedure continues at step 1036. If all of the UL CCTrCHs have been
considered (step 1058), then the procedure continues at step 1026 as described
above.
[0111] Next, CCTrCHs information with newly allocated physical channel
information, DCHs information, UL timeslot ISCP information, and power
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control information are placed into a RL addition response message (step
1028), the status flag is set to indicate a success condition (step 1030), and
the
procedure terminates (step 1020). The CCTrCH information includes the
CCTrCH identification and the DPCH information. The DPCH information
includes a list of timeslot information, a repetition period and a repetition
length. The DPCH timeslot information includes the timeslot number, the
midamble shift and burst type, the TFCI presence, and a list of code
information. The code information includes the channelized code, and the
DPCH identification. The DCHs information includes diversity indication and
choice diversity indication. The power control information includes the UL
target SIR, the maximum UL SIR, the minimum UL SIR, the initial DL
transmission power, the maximum DL transmission power, and the minimum
DL transmission power.
[0112] If the service type is NRT (step 1040), the available timeslots in the
new cell are determined (step 1062). If no timeslots are available in the new
cell (step 1064), then the status flag is set to indicate a failure condition
(step
1018) and the procedur a terminates (step 1020).
[0113] If there are timeslots available in the new cell (step 1064), then all
data rates suitable for the NRT service of the CCTrCH are retrieved from the
RRM WTRU database (step 1066) and the highest data rate is selected (step
1068). The code sets for the selected data rate are obtained (step 10'l0) and
the
normal temporary DCHs for the present CCTrCH are allocated and the
optimal solution is recorded if found (step 1072). It is noted that steps 1050
and 1072 are essentially the same; in NRT service, the DCHs are temporary.
If the resource allocation was not successful (step 1074), then a
determination
is made whether there are additional data rates to be examined (step 1076). If
there are no other data rates to be examined, then the status flag is set to
indicate a failure condition (step 1018) and the procedure terminates (step
1020). If there are other data rates to be examined (step 1076), then the next
highest data rate is selected (step 1078) and the procedure continues at step
1070. If the resource allocation was successful (step 1074), then the
procedure
continues at step 1054 as described above.
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[0114] It is noted that in connection with steps 1034, 1058, and 1060 that
either direction (DL or UL) can be performed first. As described above, the DL
direction is examined prior to the UL direction. The function 1000 will
operate
in the same manner if instead the UL was examined prior to the DL.
[0115] The steps 1050 and 1072 relate to calling the channel allocation
function of the F-DCA algorithms; this core function 300 is signal-independent
and operates in the same manner as described above in connection with
Figures 3a and 3b.
[0116] Call Admission Control for Radio Link Reconfiguration
[0117] An overview 1100 of the F-DCA CAC procedure for radio link
reconfiguration 1102 is shown in Figure 11. The F-DCA CAC procedure 1102
consists of three parts: a pre-code allocation process 1104, a code allocation
process 1106, and a post-code allocation process 1108. The pre-code allocation
process 1104 retrieves WTRU information from a radio link reconfiguration
prepare message 1110 and retrieves WTRU capability information from a
RRM WTRU database 1118. WTRU and Node B measurements are retrieved
from a RRC shared cell database 1112. A list of the available timeslots is
obtained from a RRM cell database 1116 and code sets are retrieved from an
OAM RRM table database 1114.
[0118] The code allocation process 1106 checks the code availability in the
cell, generates timeslot sequences, finds the optimal solution for the code
set
(assigns the codes in the code sets to the available timeslots and allocates
the
channelized codes from the code vectors in the RRM cell database 1116). The
post-code allocation process 1108 updates code vector information in the RRM
cell database 1116, records the allocated physical channels in the RRM WTRU
database 1118, and records the physical channel parameters and power
control information in a radio link reconfiguration ready message 1120.
[0119] In addition to the data exchanges between the processes and the
database, there are data exchanges occurring directly between the processes.
The WTRU measurements, the Node B measurements, a list of available
timeslots in the cell, a list of code sets for the specific data rate, and
WTRU
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capability information are passed from the pre-code allocation process 1104 to
the code allocation process 106. The physical channel information (a list of
timeslots and channelized codes in each timeslot) is passed from the code
allocation process 1106 to the post-code allocation process 1108.
[0120] In the present invention, the functions of the F-DCA CAC procedure
for radio link reconfiguration 1102 are modularized into two groups of
functions: signal-dependent functions whose inputs are parts of signal
messages and signal-independent functions whose inputs are independent of
signal messages. The purpose of separating the signal-dependent functions
and the signal-independent functions is to increase the reusability of the
signal-independent functions. The functions of both the pre-code allocation
process 1104 and the post-code allocation process 1108 are signal-dependent
functions. In contrast, the functions of the code allocation process 1106 are
signal-independent functions. It is to be noted that the functions of the code
allocation process 1106 can be reused by other procedures in other RRM
function implementations.
[0121] The flowcharts for functions of the F-DCA CAC procedure for radio
link reconfiguration are shown in Figures 12 and 13a-13c. Figure 12 shows a
flowchart of the main interface procedure 1200 of the F-DCA CAC for radio
link reconfiguration procedure. The procedure 1200 begins by obtaining the
RL reconfiguration prepare message (referred to hereinafter as "prepare
message"; step 1202). The prepare message contains CCTrCH information
(about a CCTrCH to be added or modified), DCH information (about a DCH to
be added or modified), and RL information with or without WTRU
measurements. The WTRU measurements include the DL ISCP and the DL P-
CCPCH RSCP. The WTRU identification and the RL identification are
extracted from the prepare message and the cell identification is retrieved
from the WTRU database (step 1204). The entry identification of the RRM cell
database is then obtained (step 1206).
[0122] A data structure is created to store measurements locally (step 1208).
This measurement data structure is stored in the F-DCA CAC function
dynamically. It is created after the F-DCA CAC function is called and is
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deleted when the F-DCA CAC function is exited. The Node B measurements
are then retrieved from the RRC shared cell database and are stored locally
(step 1210). The Node B measurements include common measurements and
dedicated measurements. The Node B common measurements include the UL
ISCP and the DL transmitted carrier power. The Node B dedicated
measurements include the DL transmitted code power.
[0123] The measurement data structure includes a list of cell measurement
records. A cell measurement record includes the cell identification and a list
of
timeslot measurement records. A timeslot measurement record contains the
timeslot number, the timeslot ISCP, the timeslot carrier power, and a list of
code measurement records. A code measurement record consists of the WTRU
identification, the radio link identification, the DPCH identification, and
the
code transmitted power.
[0124] If the WTRU measurements are included in the prepare message
(step 1212), then the WTRU measurements are extracted from the prepare
message and are stored locally in the measurement data structure (step 1214).
The physical channels are then allocated for the CCTrCHs to be added or
modified (step 1216). It is noted that the code allocation procedure (step
1216)
is the same, whether CCTrCHs are to be added or modified. The channel
allocation procedure will be discussed in greater detail in connection with
Figures 13a-13c, below. If the physical channel allocation is a success (step
1218), then a status flag is set to indicate the success condition (step 1220)
and the procedure terminates (step 1222). If the channel allocation is not
successful (step 1218), then the status flag is set to indicate a failure
condition
(step 1224) and the procedure terminates (step 1222).
[0125] If the WTRU measurements are not included in the prepare message
(step 1212), then a determination is made whether all of the DCHs are NRT
(step 1226). If all the DCHs are not NRT, then this indicates a failure
condition, and the status flag is set to indicate the failure condition (step
1224)
and the procedure terminates (step 1222). If all the DCHs are NRT (step
1228), then the RL reconfiguration type is determined (step 1230). The RL
configuration type is set based upon the CCTrCH in the RL. If the CCTrCH is
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to be added, then the RL configuration type is set to "ADDITION." If the
CCTrCH is to be modified, then the RL configuration type is set to "MODIFY."
[0126] If the RL reconfiguration type is "MODIFY", then this indicates a
failure condition, and the status flag is set to indicate the failure
condition
(step 1224) and the procedure terminates (step 1222). The failure condition
indicates that there is not enough information to process the request further.
The failure condition is reached when the RL configuration type is "MODIFY"
and the RL reconfiguration message does not include the WTRU
measurements.
[0127] If the RL reconfiguration type is "ADDITION" (step 1230), then the
low rate temporary DCHs are allocated for the CCTrCHs to be added (step
1232). The procedure then continues with step 1218, as described above.
[0128] Figures 13a-13c show a flowchart of a channel allocation procedure
1300, which is used by step 1216 of the F-DCA CAC RL reconfiguration
procedure 1200. The procedure 1300 begins by obtaining the prepare message
(step 1302) and extracting the WTRU identification and the RL identification
from the prepare message (step 1304).
[0129] The first DL CCTrCH is selected (step 1306) and the WTRU
capabilities are retrieved from the WTRU database (step 1308). The service
type for the selected CCTrCH is obtained (step 1310), and if the service type
is
RT (step 1312), then the available timeslots for the RT in the cell are
determined (step 1314). If no timeslots are available (step 1316), this
indicates
a failure condition, and a status flag is set to indicate the failure
condition
(step 1318) and the procedure terminates (step 1320).
[0130] If there are timeslots available (step 1316), then the block error rate
(BLER) for the selected CCTrCH is determined (step 1322) and the requested
data rate is calculated (step 1324). The code sets for the calculated data
rate
are obtained (step 1326) and the physical channels (timeslots and codes) for
the selected CCTrCH are allocated and the optimal solution is recorded if
found (step 1328). The allocation function in step 1328 is discussed in
greater
detail above in connection with Figures 3a and 3b. If the resource allocation
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was not successful (step 1330), then the status flag is set to indicate a
failure
condition (step 1318) and the function terminates (step 1320).
[0131] If the resource allocation was successful (step 1330), then a
determination is made whether there are additional CCTrCHs in the current
direction (i.e., DL or UL) to be examined (step 1332). If there are additional
CCTrCHs to be examined, then the next CCTrCH in the current direction is
selected (step 1334) and the procedure continues at step 1310. If there are no
additional CCTrCHs to be examined (step 1332), then a determination is made
whether the UL CCTrCHs have been examined (step 1336). If the UL
CCTrCHs have not been examined, then the first UL CCTrCH is selected (step
1338) and the procedure continues at step 1308. If all of the UL CCTrCHs
have been considered (step 1336), then the WTRU information and the
physical channel information are updated in the RRM WTRU database, and
the code vector information is updated in the RRM cell database (step 1340).
[0132] The updated WTRU information includes both the UL CCTrCH
information (for a CCTrCH to be added or modified) and the DL CCTrCH
information (for a CCTrCH to be added or modified) with newly allocated
physical channel information. The CCTrCH information includes the CCTrCH
identification, the CCTrCH status, the CCTrCH SIR target, the guaranteed
data rate, the allowed data rate, and the DPGH information. The DPCH
information includes a list of DPCH timeslot information, a repetition period,
and a repetition length. The DPCH timeslot information includes the timeslot
number, the midamble shift and burst type, the TFCT presence, and a list of
code information. The code information includes the channelized code, the
code usage status, the DPCH identification, and the code SIR target. The code
vector information includes the UL code vector information and the DL code
vector information. The UL code vector information includes a code
identification, a code block indication, and a code usage status. The DL code
vector information includes a code identification and a code usage status.
[0133] The physical channel information and the power control information
are then put into a RL reconfiguration ready message (step 1342), the status
flag is set to indicate a successful resource allocation (step 1344), and the
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procedure terminates (step 1320). The physical channel information includes a
list of timeslot information, a repetition period and a repetition length. The
timeslot information includes the timeslot number, the midamble shift and
burst type, the TFCI presence, and a list of code information. The code
information includes the channelized code and the DPCH identification. The
power control information includes the initial DL transmission power, the
maximum DL transmission power, the minimum DL transmission power, the
maximum UL SIR and the minimum UL SIR. In one implementation of the
present invention, a single data structure is used for both the request
message
and the response message since these two messages include a lot of common
information.
[0134] If the service type for the selected CCTrCH is NRT (step 1312), then
the available timeslots for the NRT in the cell are determined (step 1346). If
no timeslots are available (step 1348), the status flag is set to indicate a
failure condition (step 1318) and the procedure terminates (step 1320). If
there
are timeslots available (step 1348), then the BLEB for the selected CCTrCH is
determined (step 1350). All data rates suitable for the NRT service are
determined (step 1352) and the highest data rate is selected (step 1354). The
code sets for the selected data rate are obtained (step 1356) and the normal
temporary DCHs for the selected CCTrCH are allocated and the optimal
solution is recorded if found (step 1358). It is noted that steps 1328 and
1358
are essentially the same; in NRT service, the DCHs are temporary.
[0135] If the resource allocation was not successful (step 1360), then a
determination is made whether there are additional data rates to be examined
(step 1362). If there are no other data rates to be examined, then the status
flag is set to indicate a failure condition (step 1318) and the procedure
terminates (step 1320). If there are other data rates to be examined (step
1362), then the next highest data rate is selected (step 1364) and the
procedure continues at step 1356. If the resource allocation was successful
(step 1360), then the procedure continues at step 1332 as described above.
[0136] It is noted that in connection with steps 1306, 1336, and 1338 that
either direction (DL or UL) can be performed first. As described above, the DL
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direction is examined prior to the UL direction. The procedure 1300 will
operate in the same manner if instead the UL was examined prior to the DL.
[0137] The steps 1328 and 1358 relate to calling the channel allocation
function of the F-DCA algorithms; this core function is signal-independent and
is described above in connection with Figures 3a and 3b.
[0138] Although the preferred embodiments are described in conjunction
with a third generation partnership program (3GPP) wideband code division
multiple access (W-CDMA) system utilizing the time division duplex (TDD)
mode, the embodiments are applicable to any hybrid code division multiple
access (CDMA)/time division multiple access (TDMA) communication system.
Additionally, some embodiments are applicable to CDMA systems, in general,
using beamforming, such as the proposed frequency division duplex (FDD)
mode of 3GPP W-CDMA. While specific embodiments of the present invention
have been shown and described, many modifications and variations could be
made by one skilled in the art without departing from the scope of the
invention. The above description serves to illustrate and not limit the
particular invention in any way.
* *
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