Note: Descriptions are shown in the official language in which they were submitted.
CA 02627841 2008-03-28
METHOD, WIRELESS COMMUNICATION SYSTEM, TANGIBLE
MACHINE-READABLE MEDIUM, AND COMMUNICATION
APPARATUS FOR TRANSMITTING UPLINK HYBRID AUTOMATIC
REPEAT REQUEST PACKETS BASED ON A MULTI-HOP RELAY
STANDARD
CROSS-REFERENCES TO RELATED APPLICATIONS
This application claims the benefit of Provisional Application Serial No.
60/909,848
filed on April 3, 2007.
BACKGROUND OF THE INVENTION
Field of the Invention
The present invention relates to a method, a wireless communication system, a
tangible
machine-readable medium, and a communication apparatus for transmitting uplink
hybrid
automatic repeat request (HARQ) packets based on a multi-hop relay standard.
Descriptions of the Related Art
Although the IEEE 802.16 standard already provides greater bandwidths, lower
building
cost, better service quality and expansibility, there still exist some defects
of coverage and
signal quality of the IEEE 802.16 standard. Therefore, the IEEE 802.16j
standard working
group established a multi-hop relay study group in July, 2005 for building a
multi-hop relay
standard.
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The HARQ packet, adopted in the IEEE 802.16 standard, is an advanced data
retransmission strategy, which allows performing possible data retransmissions
directly at =the
physical layer instead of the media access control (MAC) layer and/or higher
layers. Since
the HARQ packet is able to achieve data retransmission without involving
mechanisms at the
higher layers, the delay caused by data retransmission is significantly
reduced. However, the
HARQ packet still has some defects in a multi-hop relay system, which is going
to be defined
in the IEEE 802.16j standard.
When a subscriber station (SS), such as a mobile station (MS), or a base
station (BS)
transmits data, such as the HARQ packet, in a multi-hop relay stations (MRSs)
network
through relay stations (RSs) under the IEEE 802.16j, an efficient solution is
desired for fast
exchanges of correct HARQ packets between end stations. VVith I-iARQ method,
erroneously decoded HARQ packet is required to be retransmitted from the
station to the
dominant one. If there are more than one station involved in reception of HARQ
packet, any
one of recipients, which have successfully received HARQ packet, is able to
start forwarding
data to the next hop. Therefore, BS could schedule multicast HA-RQ packets for
multi-hop
relay.
Accordingly, a solution to transmitting and relaying uplink HARQ packets based
on a
multi-hop relay standard, such as IEEE 802.16j standard, is desired.
SUMMARY OF THE INVENTION
One objective of this invention is to provide a method for transmitting uplink
HARQ
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CA 02627841 2008-03-28
packets based on a multi-hop relay standard. The method comprises the
following steps:
transmitting a plurality of multicast uplink HARQ packets from an SS to a
plurality of RSs;
replying a first acknowledgement character (ACK) from at least one of the RSs
to the BS after
the at least one of the RSs receives one of the multicast uplink HARQ packets;
transmitting an
uplink HARQ packet from the at least one of the RSs to a BS; and replying a
second ACK
from the BS to the SS after the BS receives the uplink HARQ packet. And the
uplink
HARQ packet is the same as a part of one of the multicast uplink HARQ packets.
Another objective of this invention is to provide a method for transmitting
uplink HARQ
packets based on a multi-hop relay standard. The method comprises the
following steps:
transmitting a plurality of multicast uplink HARQ packets from an SS to a
plurality of RSs;
replying first ACKs from at least two of the RSs to the BS after the at least
two of the RSs
receive the multicast uplink HARQ packets respectively; transmitting uplink
HARQ packets
from the at least two of the RSs to a BS; and replying a second ACK from the
BS to the SS
after the BS receives the uplink HARQ packets. The uplink HARQ packets are the
same as
a part of one of the multicast uplink HARQ packets respectively, and are
transmitted to the B'S
simultaneously.
Another objective of this invention is to provide a wireless communication
system for
transmitting uplink HARQ packets based on a multi-hop relay standard. The
wireless
communication system comprises a BS, an SS, and a plurality of RSs. The SS
transmits a
plurality of multicast uplink HARQ packets to the RSs. At least one of the RSs
replies a first
ACK to the BS and transmits an uplink HARQ packet to the BS after receiving
one of the
CA 02627841 2008-03-28
multicast uplink HARQ packets. The BS replies a second ACK to the SS after
receiving the
uplink HARQ packet. And the uplink HARQ packet is the same as a part of one of
the
multicast uplink HARQ packets.
Another objective of this invention is to provide a wireless communication
system for
transmitting uplink HARQ packets based on a multi-hop relay standard. The
wireless
communication system comprises a BS, an SS, and a plurality of RSs. The SS
transmits a
plurality of multicast uplink HARQ packets to the RSs. At least two of the RSs
reply ACKs
to the BS and transmit uplink HARQ packets to the BS after receiving two of
the multicast
uplink HARQ packets respectively. The BS replies a second ACK to the SS after
receiving
the uplink HARQ packets. The uplink HARQ packets are the same as a part of one
of the
multicast uplink HARQ packets respectively, and are transmitted to the BS
simultaneously.
Another objective of this invention is to provide a tangible machine-readable
medium
having executable code to cause a machine to perform a method for transmitting
uplink
HARQ packets based on a multi-hop relay standard. The method comprises the
following
steps: transmitting a plurality of multicast uplink HARQ packets from an'SS to
a plurality of
RSs; replying a first acknowledgement character (ACK) from at least one of the
RSs to tl-ie BS
after the at least one of the RSs receives one of the multicast uplink HARQ
packets;
transmitting an uplink HARQ packet from the at least one of the RSs to a BS;
and replying a
second ACK from the BS to the SS after the BS receives the uplink HARQ packet.
And the
uplink HARQ packet is the same as a part of one of the multicast uplink HARQ
packets.
Another objective of this invention is to provide a tangible machine-readable
medium
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CA 02627841 2008-03-28
having executable code to cause a machine to perform a method for transmitting
uplink
HARQ packets based on a multi-hop relay standard. The method comprises the
following
steps: transmitting a plurality of multicast uplink HARQ packets from an SS to
a plurality of
RSs; replying first ACKs from at least two of the RSs to the BS after the at
least two of the
RSs receive multicast uplink HARQ packets respectively; transmitting uplink
HARQ packets
from the at least two of the RSs to a BS; and replying a second ACK from the
BS to the SS
after the BS receives the at least one of the uplink HARQ packets. The uplink
HARQ
packets are the same as a part of one of the multicast uplink HARQ packets
respectively, and
are transmitted to the BS simultaneously.
Yet a further objective of this invention is to provide a communication
apparatus for
relaying an uplink HARQ packet based on a multi-hop relay standard. The
communication
apparatus comprises a receiving module, a processor, and a transmitting
module. TI1e
receiving module receives a multicast uplink HARQ packet from an SS. The
processor
retrieves an uplink HARQ packet in the multicast uplink HARQ packet, wherein
the uplink
HARQ packet is the same as a part of the multicast uplink HARQ packet. The
transmitting
module transmits the uplink HARQ packet to a BS.
The aforesaid method can be executed by wireless communication apparatus, such
as an
SS or an RS in the wireless communication system. By having the SS to transmit
a plurality
of multicast uplink HARQ packets to a plurality of R5s and having at least one
of the RSs to
transmit at least one of uplink HARQ packets retrieved from one of the
multicast uplink
HARQ packets to a BS, this invention can transmit uplink HARQ packets from
each SS to the
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BS of the wireless communication system based on a multi-hop relay standard.
The detailed technology and preferred embodiments implemented for the subject
invention are described in the following paragraphs accompanying the appended
drawings for
people skilled in this field to well appreciate the features of the claimed
invention.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. I is a schematic diagram illustrating a multi-hop relay wireless
communication
system of a first embodiment of the present invention;
FIG 2 is a block diagram illustrating an RS of the first embodiment;
FIG 3- FIG. 6 are schematic diagrams illustrating HARQ packets transmission of
the
first embodiment;
FIG 7 is a flow chart illustrating a second embodiment of the present
invention; and
FIG. 8 is a flow chart illustrating a third embodiment of the present
invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
As illustrated in FIG. 1, a first embodiment of the present invention is a
multi-hop relay
wireless communication system I based on a multi-hop relay standard, such as
the IEEE
802.16j standard. The multi-hop relay wireless communication system 1
comprises an
MR-BS 101, a plurality of RSs 103, 105, and an SS 107. For the sake of
simplification, two
RSs (RS, 103, and RS2 105) are illustrated. The schematic diagram of the RSs
103, 105 of
the multi-hop relay wireless communication system 1 is illustrated in FIG 2,
wherein -eacli of
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the RSs 103, 105 comprises a receiving module 1031, a processor 1033, and a
transmitting
module 1035. The receiving module 1031 is adapted to receive multicast HARQ
packets,
such as a multicast uplink HARQ packet. The processor 1033 is adapted to
retrieve an
uplink HARQ packet in the multicast uplink HARQ packet. The transmitting
module 1035
is adapted to transmit the retrieved uplink HARQ packet. The SS 107 can be
another RS or
an MS which can provide functions based on the multi-hop relay standard. The
considered
scenario is that RS, 103, RS2 105, and SS 107 can receive the information sent
fi=om the
MR-BS 101. And some types of the transmitting of uplink HARQ packets of the
multi-hop
relay wireless conununication system I are illustrated in FIG. 3 to FIG. 6.
FIG. 3 illustrates one type of hop-by-hop transmitting HARQ packets of the
multi-hop
relay wireless communication system 1 in an uplink case. In FIG. 3, the MI2-
B'S 101
broadcasts MAPs MB to the RS, 103, RS2 105, and SS 107 first. The MR-BS 101
assigns
the RS, 103 and the RS2 105 to be in a multicast HARQ group. It means that the
RS, 103
and the RS2 105 can receive each uplink HARQ packet from the SS 107 and reply
an ACK or
a non-acknowledgement character (NACK) to the MR-BS 101. Then the SS 107
transmits a
plurality of multicast uplink HARQ packets MD, to the RS, 103 and the RS2 105.
After the
RS, 103 and the RS2 105 receive the multicast uplink HARQ packets MDI, both
the 12S, 103
and the RS2 105 detennine whether the received multicast uplink HARQ packet
MD, is
correct or not. It is assumed that the multicast uplink HARQ packet MD,
received by the
RSI 103 is not correct (shown by the dash line) and the multicast uplink HARQ
packet MD,
received by the RS2 105 is correct. Thus, the RS, 103 transmits an NACK NRI_B
to the
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MR-BS 101 and the RS2 105 transmits an ACK AR2-B to the MR-BS 101. The MR-BS
101
is able to know the transmission statuses of the RS, 103 and the RS2 105 by
the NACK N1z,_13
and the ACK AR2.s.
To be more specific, by receiving the NACK NRI-B from the RS, 103 and
receiving the
ACK ARZ_B from the RS2 105, the MR-BS 101 knows that the SS 107 can continue
to transmit
uplink HARQ packets through the RS2 105 but not the RS, 103. After that, the
MR-BS 101
broadcasts new MAPs MB to the RS, 103, RS2 105, and SS 107. Then the RS2 105
retrieves
an uplink HARQ packet D, in the multicast uplink HARQ packet MD, and transmits
the
uplink HARQ packet D, to the MR-BS 101. Finally, the MR-BS 101 determines
whether the
uplink HARQ packet D, is correct or not. If the uplink HARQ packet Dl is
correct, the
MR-BS 101 broadcasts another MAPs MB to the RS, 103, RS2 105, and SS 107, and
then
transmits an ACK AB-M to the SS 107 through the RS2 105. According to the
receipt of the
ACK and/or NACK, the MR-BS 101 can schedule the proper RS to forward uplink
HARQ
packets.
FIG. 4 illustrates one type of end-to-end transmitting HARQ packets of the
multi-hop
relay wireless communication system 1 in an uplink case. In FIG. 4, the MR-BS
101
broadcasts MAPs MB to the RS, 103, RS2 105, and SS 107 first. The MR-BS 101
assigns
the RS1 103 and the RS2 105 to be in a multicast HARQ group and the MR-BS 101
also
allocates bandwidth for RS2 105 to forward HARQ packets to the MR-BS 101. It
means that
the MR-BS 101 schedules RS, 103 and RS2 105 to receive multicast uplink HARQ
packets
and pre-schedules RS2 105 to forward uplink HARQ packets from the SS 107 to
the MR-BS
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101. Then the SS 107 intends to transmit a plurality of multicast uplink HARQ
packets MD,
to the RS, 103 and the RS2 105. After the RS, 103 and the RS2 105 receive the
multicast
uplink HARQ packets MD1, the RS, 103 determines whether the received multicast
uplink
HARQ packet MD, is correct or not, and the RS2 105 determines whether the
received
multicastuplink HARQ packet MD, is correct or not. It is assumed that the
multicast uplink
HARQ packet MD, received by the RS, 103 is not correct (shown by the dash
line), the
multicast uplink HARQ packet MD, received by the RS2 105 is coi-rect, so the
RS, 103
transmits an NACK NRI_B to the MR-BS 101.
The RS, 103 fails to receive the multicast uplink HARQ packet MD1, while the
RS2 105
correctly receives the multicast uplink HARQ packet MDI. Consequently, the RS2
105 can
continue to transmit uplink HARQ packets to the MR-BS 101. After that, the RS2
105
retrieves the uplink HARQ packet D, in the multicast uplink HARQ packet MD,
and directly
transmits the uplink HARQ packet D, to the MR-BS 101. Finally, the MR-BS 101
determines whether the uplink HARQ packet D, is con=ect or not. If the uplink
HARQ
packet D, is correct, the MR-BS 101 broadcasts new MAPs MB to the RS, 103, RS2
105, and
SS 107, and then transmits an ACK Aa_M to the SS 107 through the RS2 105.
FIG 5 illustrates one type of enhanced hop-by-hop transmitting HARQ packets of
the
multi-hop relay wireless communication system 1 in an uplink ease. In FIG. 5,
the MR-BS
101 broadcasts MAPs MB to the RS, 103, RS2 105, and SS 107 first. The MR-BS
101
assigns the RS, 103 and the RS2 105 to be in a multicast HARQ group. It means
that the
RS, 103 and the RS2 105 can receive each uplink HARQ packet from the'SS 107
and reply an
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ACK or an NACK to the MR-BS 101. Then the SS 107 transmits a plurality of
multicast
uplink HARQ packets MD, to the RS, 103 and the RS2 105. After the RS, 103 and
the RS2
105 receive the multicast uplink HARQ packets MDI, both the RS, 103 and the
RS2 105
determine whether the received multicast uplink HARQ packet MD, is correct or
not. It is
assumed that the multicast uplink HARQ packet MDl received by the RS, 103 is
=correct and
the multicast uplink HARQ packet MD, received by the RS2 105 is also correct.
Thus, the
RS, 103 transmits an ACK ARI_B to the MR-BS 101 and the RS2 105 transmits an
ACK AR2_13
to the MR-BS 101. The MR-BS 101 is able to know the transmission statuses of
the RS,
103 and the RS2 105 by the ACK ARI_B and the ACK AR2_B.
To be more specific, by receiving the ACK AR,-B from the RS, 103 and receiving
the
ACK AR2_B from the RS2 105, the MR-BS 101 knows that the SS 107 can continue
to transniit
uplink HARQ packets through the RS, 103 and/or the RS2 105. After that, the MR-
BS 101
broadcasts new MAPs MB to the RS, 103, RS2 105, and SS 107. Then the RS, 103
retrieves
an uplink HARQ packet D, in the multicast uplink HARQ packet IVID, and
transmits the
uplink HARQ packet D, to the MR-BS 101. Similarly, the RS2 105 retrieves
another uplink
HARQ packet D, in the multicast uplink HARQ packet MD, and transmits the
uplink 1-iARQ
packet D, to the MR-BS 101. By appropriate algorithm and the above MAPs MB,
the uplink
HARQ packets D, transmitted by the RS, 103 and RS2 105 will anive to the MR-BS
101
simultaneously. Finally, the MR-BS 101 detennines whether the uplink HARQ
packets D,
are correct or not. If the uplink HARQ packets D, are correct, the MR-BS 101
broadcasts
another MAPs MB to the RS, 103, RS2 105, and SS 107, and then transmits ACKs
Aa_M to the
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SS 107 through the RS, 103 and RS2 105. According to the receipt of the ACK
andlor
NACK, the MR-BS 101 can schedule the proper RS to forward uplink HARQ packets.
FIG. 6 illustrates one type of enhanced end-by-end transmitting HARQ packets
of the
multi-hop relay wireless communication system 1 in an uplink case. In FIG 6,
the MR-BS
101 broadcasts MAPs MB to the RSI 103, RS2 105, and SS 107 first. The MR-BS
101
assigns the RS, 103 and the RS2 105 to be in a multicast HARQ group. Then the
SS 107
transmits a plurality of multicast uplink HARQ packets MD, to the RS, 103 and
the RS2 105.
After the RS, 103 and the RS2 105 receive the multicast uplink HARQ packets
MDI, both the
RS] 103 and the RS2 105 determine whether the received multicast uplink HARQ
packets
MDl are correct or not. It is assumed that the multicast uplink HARQ packet
MD, received
by the RS1 103 is correct and the multicast uplink HARQ packet MD, received by
the RS2
105 is also correct. After that, the RS, 103 retrieves an uplink HARQ packet
D, in the
multicast uplink HARQ packet MD, and transmits the uplink HARQ packet D, to
the MR-BS
101.
Similarly, the RS2 105 retrieves another uplink HARQ packet D, in the
multicast uplink
HARQ packet MD, and transmits the uplink HARQ packet D, to the MR-BS 101. By
appropriate algorithm, the uplink HARQ packets D, transmitted by the I'iS, 103
and RS2 105
will arrive to the MR-BS 101 simultaneously. Then, for MR-BS 101 to confirm
that D, is
correct or not, an optional mechanism may be implemented that the RS) 103.
transmits an
ACK ARi.B to the MR-BS 101 and the RS2 105 transmits an ACK AR2_B to the MR-BS
101.
Finally, the MR-BS 101 determines whether the uplink HARQ packets D, are
correct or not.
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If the uplink HARQ packets D, are correct, the MR-BS 101 broadcasts new MAPs
MB to the
RS, 103, RS2 105, and SS 107, and then transmits ACKs AB_M to the SS 107
through the RS,
103 and RS2 105.
The ACKs and NACKs which are illustrated in FIG. 3 to FIG. 6 are transmitted
by one
or more than one specific channels, in which those skilled in the art can
understand the
corresponding transmission of the ACKs and NACKs by IEEE 802.16j standard, and
thus no
detailed explanation is unnecessary.
A second embodiment of this invention is a method for transmitting uplink HARQ
packets based on a multi-hop relay standard, which is a method applied to the
multi-hop relay
wireless communication system I described in the first embodiment. More
specificaily, the
HARQ packets transmission method of the second embodiment which is illustrated
in F1G. 7
can be implemented by an application program controlling various modules of a
wireless
communication apparatus in the multi-hop relay wireless communication system
1. This
application program may be stored in a tangible machine-readable medium, such
as a read
only memory (ROM), a flash memory, a floppy disk, a hard disk, a compact disk,
a mobile
disk, a magnetic tape, a database accessible to networks, or any other storage
media with the
same function and well known to those skilled in the art.
The second embodiment of this invention illustrates hop-by-hop transmitting
HARQ
packets of the multi-hop relay wireless communication system I in an uplink
case. In step
701, a plurality of RSs, such as the RS, 103 and RS2 105, are grouped into a
multicast HARQ
group. Next in step 703, MAPs are broadcasted from a BS, such as the MR-BS
101, to the
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CA 02627841 2008-03-28
RSs and an SS, such as the SS 107. In step 705, a plurality of first uplink
HARQ packets are
transmitted from the SS to the RSs. In step 707, a first ACK is replied 'from
at least one of
the RSs, such as one of the RS, 103 and RS2 105, to the BS after the at least
one of the RSs
receives one of the first uplink HARQ packets. In step 709, a second uplink
HARQ packet
is retrieved in the first uplink HARQ packet by the at least one of the RSs.
In step 711, new
MAPs are broadcasted from the BS to the RSs and the SS. In step 713, the
second uplink
HARQ packet is transmitted from the at least one of the RSs to the BS.
Finally, in step 715,
a second ACK is replied from the BS to the 'SS directly and/or through one of
the RSs after
the BS receives the second uplink HARQ packet.
In addition to the steps revealed in FIG. 7, the second embodiment can also
execute all
the operations of the first embodiment, in which those skilled in the art can
understand the
corresponding steps and operations of the second embodiment by the explanation
of the first
embodiment, and thus detailed description in this regard in unnecessary.
A third embodiment of this invention is a method for transmitting uplink HARQ
packets
based on a multi-hop relay standard, which is a method applied to the multi-
hop relay wireless
communication system I described in the first embodiment. More specifically,
the HARQ
packets transmission method of the third embodiment which is illustrated in
FIG. 8'can be
implemented by an application program controlling various modules of a
wireless
communication apparatus in the multi-hop relay wireless communication system
1. This
application program may be stored in a tangible machine-readable mediuni, such
as a read
only memory (ROM), a flash memory, a floppy disk, a hard disk, a compact disk,
a mobile.
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CA 02627841 2008-03-28
disk, a magnetic tape, a database accessible to networks, or any other storage
media with the
same function and well known to those skilled in the art.
The third embodiment of this invention illustrates enhanced hop-by-hop
transmitting
HARQ packets of the multi-hop relay wireless communication system 1 in an
uplink case.
In step 801, a plurality of RSs, such as the RS, 103 and RS2 105, are grouped
into a multicast
HARQ group. Next in step 803, MAPs are broadcasted from a BS, such as the MR-
BS 101,
to the RSs and an SS, such as the SS 107. In step 805, a plurality of first
uplink HARQ
packets are transmitted from the SS to the RSs. In step 807, first ACKs are
replied 'from at
least two of the RSs, such as the RS, 103 and RS2 105, to the BS after the at
least two of 3ale
RSs receive two of the first uplink HARQ packets respectively. In step 809,
second uplink
HARQ packets are retrieved in the first uplink HARQ packets by the at least
two of the RSs
respectively. In step 811, new MAPs are broadcasted from the BS to the RSs and
the 'SS.
In step 813, the second uplink HARQ packets are simultaneously transmitted
from the at least
two of the RSs to the BS. Finally, in step 815, second ACKs are replied from
the BS to the
SS directly and/or through one of the RSs after the BS receives the second
uplink HARQ
packets.
In addition to the steps revealed in FIG. 8, the third embodiment can also
execute all the
operations of the first embodiment, in which those skilled in the art can
understand the
corresponding steps and operations of the third embodiment by the explanation
of the first
embodiment, and thus detailed description in this regard is unnecessary.
Accordingly, by having an SS to transmit multicast uplink HARQ packets to a
plurality
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CA 02627841 2008-03-28
of RSs and having one of the RSs to transmit at least one of uplink HARQ
packets retrieved
from one of the multicast uplink HARQ packets to a BS, this invention can
transmit uplink
HARQ packets from each SS to the BS of the wireless communication system based
on a
multi-hop relay standard.
The above disclosure is related to the detailed technical contents and
inventive features
thereof. People skilled in this field may proceed with a variety of
modifications and
replacements based on the disclosures and suggestions of the invention as
described without
departing from the characteristics thereof. Nevertheless, although such
modifications and
replacements are not fully disclosed in the above descriptions, they have
substantially been
covered in the following claims as appended.
