U.S. patent number RE45,635 [Application Number 13/869,544] was granted by the patent office on 2015-07-28 for methods to index the preambles in the bandwidth request channel.
This patent grant is currently assigned to SAMSUNG ELECTRONICS CO., LTD.. The grantee listed for this patent is Samsung Electronics Co., Ltd.. Invention is credited to Kaushik Josiam, Ying Li, Zhouyue Pi, Hwasun Yoo.
United States Patent |
RE45,635 |
Josiam , et al. |
July 28, 2015 |
Methods to index the preambles in the bandwidth request channel
Abstract
For use in a wireless communication network, a mobile station
configured to determine a preamble sequence from a set of indexed
preamble sequences by generating an index of the preamble sequence
from a B-bit message is provided. The mobile station is configured
to group the B bits of the message into n groups, each group having
a substantially equal number of bits. The mobile station is also
configured to generate a parity bit from each of the n groups. The
mobile station is further configured to determine the index of the
preamble sequence based on the n parity bits. The mobile station is
still further configured to transmit the preamble sequence
corresponding to the index of the preamble sequence. A base station
configured to recover the B-bit message using the received signal
from the mobile station is also provided.
Inventors: |
Josiam; Kaushik (Dallas,
TX), Pi; Zhouyue (Allen, TX), Li; Ying (Garland,
TX), Yoo; Hwasun (Gyeonggi-do, KR) |
Applicant: |
Name |
City |
State |
Country |
Type |
Samsung Electronics Co., Ltd. |
Suwon-si, Gyeonggi-do |
N/A |
KR |
|
|
Assignee: |
SAMSUNG ELECTRONICS CO., LTD.
(Suwon-Si, KR)
|
Family
ID: |
43449962 |
Appl.
No.: |
13/869,544 |
Filed: |
April 24, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
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61270897 |
Jul 14, 2009 |
|
|
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Reissue of: |
12783235 |
May 19, 2010 |
8204147 |
Jun 19, 2012 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04L
29/0653 (20130101); H04W 72/0413 (20130101); H04L
69/22 (20130101); H04L 5/0048 (20130101); H04W
74/004 (20130101) |
Current International
Class: |
H04L
27/00 (20060101); H04L 29/06 (20060101); H04L
5/00 (20060101) |
Field of
Search: |
;375/260,295 ;455/103
;370/320 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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1 705 838 |
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Sep 2006 |
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EP |
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2012-520003 |
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Aug 2012 |
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JP |
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10-2005-0029395 |
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Mar 2005 |
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KR |
|
2292669 |
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Jan 2007 |
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RU |
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2295843 |
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Mar 2007 |
|
RU |
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2348110 |
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Feb 2009 |
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RU |
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WO 2005/040960 |
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May 2005 |
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WO |
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WO 2005/040960 |
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May 2005 |
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WO |
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WO 2007/024101 |
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Mar 2007 |
|
WO |
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WO 2007/149729 |
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Dec 2007 |
|
WO |
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WO 2010/147431 |
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Dec 2010 |
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WO |
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Other References
Translation of Notification of Reason for Rejection issued on Dec.
17, 2013, in connection with Japanese Application No. 2012-520542,
9 pages. cited by applicant .
Heejeong Cho, et al., "BW-REQ Information Contents for the Quick
Access," IEEE 802.16m-09/1422, URL,
http://grouper.ieee.org/groups/802/16/tgm/contrib/S80216m-09.sub.--1422.p-
pt, 6 pages. cited by applicant .
Heejeong Cho, et al., "BW-REQ Information Contents for the Quick
Access," IEEE 802.16m-09/1422, URL,
http://grouper.ieee.org/groups/802/16/tgm/contrib/S80216m-09.sub.--1422.p-
pt, 8 pages. cited by applicant .
Translated Japanese Office Action dated Jul. 26, 2013 in connection
with Japanese Patent Application No. 2012-520542, 8 pages. cited by
applicant .
Shkumbin Hamiti; "IEEE 802.16m System Description Document" IEEE
802.16 Broadband Wireless Access Working Group; Nokia; May 31,
2009; 5 pages. cited by applicant .
Yoo, et al.; "Proposed PHY structure of Bandwidth Request Channel
for IEEE 802.16m Amendment Text"; IEEE 802.16 Broadband Wireless
Access Working Group; Samsung Electronics Co., Ltd; Jul. 6, 2009; 8
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Zhu, et al.; "Proposed text changes to the IEEE 802.16m SDD
(802.16m-08/003r6), Section 11.9.2.5 on the Bandwidth Request
Channel"; IEEE 802.16 Broadband Wireless Access Working Group;
Intel Corporation; Jan. 5, 2009; 8 pages. cited by applicant .
Yen, et al.; "Quick Access Message for IEEE 802.16m" National
Central University; May 4, 2009; 11 pages. cited by applicant .
Australian Office Action dated Aug. 22, 2013 in connection with
Australial Patent Application No. 2010271668, 5 pages. cited by
applicant .
Translated Russian Office Action dated May 23, 2013 in connection
with Russian Patent Application No. 2012105005/08(007557), 15
pages. cited by applicant .
European Search Report dated Jun. 4, 2014 in connection with
European Patent Application No. 10169491.7, 8 pages. cited by
applicant .
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Management and QoS DG AWD text with DG comment resolution"; Apr.
27, 2009; XP017797814; 25 pages. cited by applicant .
International Search Report dated Jan. 25, 2011 in connection with
International Patent Application No. PCT/KR2010/004553. cited by
applicant.
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Primary Examiner: Odom; Curtis
Claims
What is claimed is:
1. For use in a wireless communication network, a mobile station
configured to determine a preamble sequence from a set of indexed
preamble sequences by generating an index of the preamble sequence
from a B-bit message, the mobile station comprising: a processor
configured to: group the B bits of the message into n groups, each
group having a substantially equal number of bits; generate a
parity bit from each of the n groups; and determine the index of
the preamble sequence based on the n parity bits; and transceiver
circuitry configured to transmit the preamble sequence
corresponding to the index of the preamble sequence.
2. The mobile station as set forth in claim 1, wherein B.sub.MS
bits of the B-bit message comprise a mobile station ID,
(B-B.sub.MS) bits of the B-bit message comprise a bandwidth
indicator, n=3, and each parity bit is generated by:
p.sub.i=mod(b.sub.i+b.sub.i+3+b.sub.i+6+ . . . +b.sub.i+.left
brkt-bot.b.sub.MS.sub.-3.right
brkt-bot.-1+d.sub.(B-B.sub.MS.sub.-1)-2+i, 2), 0.ltoreq.i<3,
wherein b.sub.0,b.sub.1,b.sub.2,L,b.sub.B.sub.MS.sub.-1 represent
the B.sub.MS bits of the mobile station ID, wherein
d.sub.0,d.sub.1,d.sub.2,L,d.sub.(B-B.sub.MS.sub.-1) represent the
(B-B.sub.MS) bits of the bandwidth indicator, and wherein mod (.,2)
represents a bitwise XOR operation.
3. The mobile station as set forth in claim 1, wherein the index of
the preamble sequence is determined by a decimal equivalent of the
n parity bits.
4. The mobile station as set forth in claim 1, wherein the mobile
station is further configured to transmit a portion of the B-bit
message in a quick access message along with the preamble
sequence.
5. The mobile station as set forth in claim 2, wherein the mobile
station is further configured to randomize the B.sub.MS bits of the
mobile station ID using a .pi.(.) randomizer function before
generating the plurality of parity bits.
6. For use in a wireless communication network, a base station
configured to process a B-bit message from a mobile station, the
message including a preamble sequence and a quick access message,
the base station comprising: transceiver circuitry configured to
receive the message from the mobile station; and a processor
configured to: determine a preamble index corresponding to the
received preamble sequence, the preamble index corresponding to n
parity bits; determine a (B-n) bit portion of the B bit message
from the quick access message; group the (B-n) bits into n groups,
each group having a substantially equal number of bits; distribute
the n parity bits to the n groups; and recover the n bit portion of
the B bit message using a bit-wise XOR operation on the bits in
each of the n groups and each of the n parity bits.
7. The base station as set forth in claim 6, wherein: a portion of
the B-bit message is received using the quick access message and
the parity bits; the entire B-bit message is constructed; n=3; and
the portion of the message not transmitted in the quick access
message is generated by: d.sub.i=mod(b.sub.i+b.sub.i+3+b.sub.i+6+ .
. . b.sub.i+.left brkt-bot.b.sub.MS.sub.-3.right
brkt-bot.-1+p.sub.i, 2), 0.ltoreq.i<3 wherein: b.sub.MS
represents a plurality of bits of the B-bit message that comprise a
mobile station ID, b.sub.i represents the portion of the B-bit
message transmitted in the quick access message, p.sub.i represents
the parity bits corresponding to the index of the preamble
sequence, and mod (.,2) represents a bitwise XOR operation.
8. The base station as set forth in claim 6, wherein the parity
bits are determined by a binary equivalent of the preamble index of
the received preamble sequence.
9. The base station as set forth in claim 7, wherein the B.sub.MS
bits of the mobile station ID are randomized by a .pi.(.)
randomizer function.
10. The base station as set forth in claim 6, wherein the base
station is configured to receive the message from the mobile
station on a bandwidth request channel.
11. For use in a wireless communication network, a mobile station
configured to determine a preamble sequence from a set of indexed
preamble sequences by generating an index of the preamble sequence
from a message, the message having B bits, B.sub.MS bits of the B
bits comprising a mobile station ID and (B-B.sub.MS) of the B bits
comprising a bandwidth indicator, the mobile station comprising: a
processor configured to: generate a plurality of parity bits from
the B.sub.MS station ID bits; generate a plurality of preamble bits
from the plurality of parity bits; and replace a final plurality of
bits of the B-bit quick access message with the plurality of
preamble bits.
12. The mobile station as set forth in claim 11, the mobile station
further configured to randomize the B.sub.MS bits of the mobile
station ID using a .pi.(.) randomizer function before generating
the plurality of parity bits.
13. The mobile station as set forth in claim 11, wherein the
plurality of parity bits are represented by:
b.sub.PG1=mod(b.sub.0+b.sub.1+b.sub.2+ . . . +b.sub.k, 2)
b.sub.PG2=mod(b.sub.k+1+b.sub.k+2+ . . . +b.sub.2k, 2)
b.sub.PG3=mod(b.sub.2k+1+b.sub.2k+2+ . . . +b.sub.3k, 2), wherein
the plurality of preamble bits are represented by:
p.sub.0=mod(d.sub.(B-Bms-1)-2+b.sub.PG1, 2)
p.sub.1=mod(d.sub.(B-Bms-1)-1+b.sub.PG2, 2)
p.sub.2=mod(d.sub.(B-Bms-1)+b.sub.PG3, 2), wherein
b.sub.0,b.sub.1,b.sub.2L,b.sub.B.sub.MS.sub.-1 represent the
B.sub.MS bits of the mobile station ID, wherein d.sub.(B-Bms-1),
d.sub.(B-Bms-1)-1, d.sub.(B-Bms-1)-2 represent bits of the
bandwidth indicator, wherein k=.left brkt-bot.B.sub.MS/3.right
brkt-bot., and wherein mod(.,2) represents a bitwise XOR
operation.
14. The mobile station as set forth in claim 11, wherein the
plurality of parity bits are generated using a hash function.
15. The mobile station as set forth in claim 11, wherein the
plurality of parity bits are generated using a cyclic redundancy
check (CRC) generator.
16. A wireless communication network comprising a plurality of
mobile stations and at least one base station, each mobile station
configured to determine a preamble sequence from a set of indexed
preamble sequences by generating an index of the preamble sequence
from a B-bit message, each mobile station configured to: group the
B bits into n groups, each group having a substantially equal
number of bits; generate a parity bit from each of the n groups;
determine the index of the preamble sequence based on the n parity
bits; and transmit to the at least one base station the preamble
sequence corresponding to the index of the preamble sequence.
17. The wireless communication network as set forth in claim 16,
wherein B.sub.MS bits of the B-bit message comprise a mobile
station ID, (B-B.sub.MS) bits of the B-bit message comprise a
bandwidth indicator, n=3, and each parity bit is generated by:
p.sub.i=mod(b.sub.i+b.sub.i+3+b.sub.i+6+ . . . +b.sub.i+.left
brkt-bot.b.sub.MS.sub.-3.right
brkt-bot.-1+d.sub.(B-B.sub.MS.sub.-1)-2+i, 2), 0.ltoreq.i<3,
wherein b.sub.0,b.sub.1,b.sub.2,L,b.sub.B.sub.MS.sub.-1 represent
the B.sub.MS bits of the mobile station ID, wherein
d.sub.0,d.sub.1,d.sub.2,L,d.sub.(B-B.sub.MS.sub.-1) represent the
(B-B.sub.MS) bits of the bandwidth indicator, and wherein mod (.,2)
represents a bitwise XOR operation.
18. The wireless communication network as set forth in claim 16,
wherein the index of the preamble sequence is determined by a
decimal equivalent of the n parity bits.
19. The wireless communication network as set forth in claim 16,
wherein each mobile station is further configured to transmit a
portion of the B-bit message in a quick access message along with
the preamble sequence.
20. The wireless communication network as set forth in claim 17,
where each mobile station is further configured to randomize the
B.sub.MS bits of the mobile station ID using a .pi.(.)randomizer
function before generating the plurality of parity bits.
21. For use in a wireless communication network, a base station
configured to decode a quick access message, the quick access
message comprising a mobile station ID and a bandwidth
size/priority indicator, the base station comprising: transceiver
circuitry configured to receive the quick access message and a
preamble sequence from a mobile station; and a processor configured
to: determine a n-bit preamble index corresponding to the received
preamble sequence, the preamble index corresponding to n parity
bits; determine a B-bit portion of the quick access message,
wherein B.sub.MS bits comprise the mobile station ID and B-B.sub.MS
bits comprise the bandwidth size/priority indicator, recover then
parity bits using a bit-wise XOR operation on then bits of the
preamble index and n of the B-B.sub.MS bits of the bandwidth
size/priority indicator; and use the n parity bits to perform a
parity check on the B.sub.MS bits of the mobile station ID.
22. The base station as set forth in claim 21, the processor
further configured to: use a .pi.(.) randomizer function to
randomize the bits of the mobile station ID.
23. The base station as set forth in claim 21, wherein n=3 and the
3 bits of the preamble index are used to recover the 3 parity bits,
the 3 recovered parity bits represented by:
rb.sub.PG1=mod(d.sub.(B-Bms-1)-2+p.sub.0, 2)
rb.sub.PG2=mod(d.sub.(B-Bms-1)-1+p.sub.1, 2)
rb.sub.PG3=mod(d.sub.(B-Bms-1)+p.sub.2, 2), wherein the 3 recovered
parity bits are compared to the 3 parity bits, the 3 parity bits
represented by: b.sub.PG1=mod(b.sub.0+b.sub.1+b.sub.2+ . . .
+b.sub.k, 2) b.sub.PG2=mod(b.sub.k+1+b.sub.k+2+ . . . +b.sub.2k, 2)
b.sub.PG3=mod(b.sub.2k+1+b.sub.2k+2+ . . . +b.sub.3k, 2) wherein
b.sub.0,b.sub.1,b.sub.2, . . . , b.sub.B.sub.MS.sub.-1 represent
the bits of the mobile station ID, wherein d.sub.(B-Bms-1),
d.sub.(B-Bms-1)-1, d.sub.(B-Bms-1)-2 represent bits of the
bandwidth size/priority indicator, wherein k=.left
brkt-bot.B.sub.MS/3.right brkt-bot., and wherein mod(.,2)
represents a bitwise XOR operation.
24. The base station as set forth in claim 21, wherein the
plurality of parity bits are generated using a hash function.
25. The base station as set forth in claim 21, wherein the
plurality of parity bits are generated using a cyclic redundancy
check (CRC) generator.
26. For use in a wireless communication network, a method of
indexing a preamble from a set of indexed preamble sequences using
a quick access message, the quick access message having B bits,
B.sub.MS bits of the B bits comprising a mobile station ID and
(B-B.sub.MS) of the B bits comprising a bandwidth indicator, the
method comprising the steps of: grouping the B.sub.MS bits and
(B-B.sub.MS) bits into three groups, each group having a
substantially equal number of bits; generating a parity bit for
each of the three groups; and replacing a final three bits of the
B-bit quick access message with the three parity bits.
27. The method as set forth in claim 26, wherein each parity bit is
represented by: p.sub.i=mod(b.sub.i+b.sub.i+3+b.sub.i+6+ . . .
+b.sub.i+.left brkt-bot.b.sub.MS.sub.-3.right
brkt-bot.-1+d.sub.(B-B.sub.MS.sub.-1)-2+i, 2), 0.ltoreq.i<3
wherein b.sub.0,b.sub.1,b.sub.2,L,b.sub.B.sub.MS.sub.-1 represent
the B.sub.MS bits of the mobile station ID, wherein
d.sub.0,d.sub.1,d.sub.2,L,d.sub.(B-B.sub.MS.sub.-1) represent the
(B-B.sub.MS) bits of the bandwidth indicator, and wherein mod(.,2)
represents a bitwise XOR operation.
28. The method as set forth in claim 26, wherein the quick access
message is used in a bandwidth request channel.
29. The method as set forth in claim 26, wherein the bandwidth
indicator is a bandwidth size/priority indicator.
30. For use in a wireless communication network, a method of
indexing a preamble from a set of indexed preamble sequences using
a quick access message, the quick access message having B bits,
B.sub.MS bits of the B bits comprising a mobile station ID and
(B-B.sub.MS) of the B bits comprising a bandwidth indicator, the
method comprising the steps of: generating a plurality of parity
bits from the B.sub.MS station ID bits; generating a plurality of
preamble bits from the plurality of parity bits; and replacing a
final plurality of bits of the B-bit quick access message with the
plurality of preamble bits.
31. The method as set forth in claim 30, further comprising the
step of: before generating the plurality of parity bits,
randomizing the B.sub.MS bits of the mobile station ID using a
.pi.(.) randomizer function.
32. The method as set forth in claim 30, wherein the plurality of
parity bits are represented by:
b.sub.PG1=mod(b.sub.0+b.sub.1+b.sub.2+ . . . +b.sub.k, 2)
b.sub.PG2=mod(b.sub.k+1+b.sub.k+2+ . . . +b.sub.2k, 2)
b.sub.PG3=mod(b.sub.2k+1+b.sub.2k+2+ . . . +b.sub.3k, 2), wherein
the plurality of preamble bits are represented by:
p.sub.0=mod(d.sub.(B-Bms-1)-2+b.sub.PG1, 2)
p.sub.1=mod(d.sub.(B-Bms-1)-1+b.sub.PG2, 2)
p.sub.2=mod(d.sub.(B-Bms-1)+b.sub.PG3, 2), wherein
b.sub.0,b.sub.1,b.sub.2,L,b.sub.B.sub.MS.sub.-1 represent the
B.sub.MS bits of the mobile station ID, wherein d.sub.(B-Bms-1),
d.sub.(B-Bms-1)-1, d.sub.(B-Bms-1)-2 represent bits of the
bandwidth indicator, wherein k=.left brkt-bot.B.sub.MS/3.right
brkt-bot., and wherein mod(.,2) represents a bitwise XOR
operation.
33. The method as set forth in claim 30, wherein the plurality of
parity bits are generated using a hash function.
34. The method as set forth in claim 30, wherein the plurality of
parity bits are generated using a cyclic redundancy check (CRC)
generator.
35. For use in a base station in a wireless communication network,
a method of processing a B-bit message from a mobile station, the
message including a preamble sequence and a quick access message,
the method comprising: receiving the message from the mobile
station; determining a preamble index corresponding to the received
preamble sequence, the preamble index corresponding to n parity
bits; determining a (B-n) bit portion of the B bit message from the
quick access message; grouping the (B-n) bits into n groups, each
group having a substantially equal number of bits; distributing the
n parity bits to the n groups; and recovering the n bit portion of
the B bit message using a bit-wise XOR operation on the bits in
each of the n groups and each of the n parity bits.
36. The method as set forth in claim 35, wherein: a portion of the
B-bit message is received using the quick access message and the
parity bits; the entire B-bit message is constructed; n=3; and the
portion of the message not transmitted in the quick access message
is generated by: d.sub.i=mod(b.sub.i+b.sub.i+3+b.sub.i+6+ . . .
+b.sub.i+.left brkt-bot.b.sub.MS.sub./3.right
brkt-bot.-1+p.sub.i.sub.i, 2), 0.ltoreq.i<3 wherein: b.sub.MS
represents a plurality of bits of the B-bit message that comprise a
mobile station ID, b.sub.i represents the portion of the B-bit
message transmitted in the quick access message, p.sub.i represents
the parity bits corresponding to the index of the preamble
sequence, and mod (.,2) represents a bitwise XOR operation.
37. The method as set forth in claim 35, further comprising:
determining the parity bits by a binary equivalent of the preamble
index of the received preamble sequence.
38. The method as set forth in claim 36, further comprising:
randomizing the B.sub.MS bits of the mobile station ID by a .pi.(.)
randomizer function.
39. The method as set forth in claim 35, further comprising:
receiving the message from the mobile station on a bandwidth
request channel.
40. For use in a base station in a wireless communication network,
a method of decoding a quick access message, the quick access
message comprising a mobile station ID and a bandwidth
size/priority indicator, the method comprising: receiving the quick
access message and a preamble sequence from a mobile station;
determining a n-bit preamble index corresponding to the received
preamble sequence, the preamble index corresponding to n parity
bits; determining a B-bit portion of the quick access message,
wherein B.sub.MS bits comprise the mobile station ID and B-B.sub.MS
bits comprise the bandwidth size/priority indicator; recovering the
n parity bits using a bit-wise XOR operation on the n bits of the
preamble index and n of the B-B.sub.MS bits of the bandwidth
size/priority indicator; and using the n parity bits to perform a
parity check on the B.sub.MS bits of the mobile station ID.
41. The method as set forth in claim 40, the method further
comprising: randomizing the bits of the mobile station ID using a
.pi.(.) randomizer function.
42. The method as set forth in claim 40, wherein n=3 and the 3 bits
of the preamble index are used to recover the 3 parity bits, the 3
recovered parity bits represented by:
rb.sub.PG1=mod(d.sub.(B-Bms-1)-2+p.sub.0, 2)
rb.sub.PG2=mod(d.sub.(B-Bms-1)-1+p.sub.1, 2)
rb.sub.PG3=mod(d.sub.(B-Bms-1)+p.sub.2, 2) wherein the 3 recovered
parity bits are compared to the 3 parity bits, the 3 parity bits
represented by: b.sub.PG1=mod(b.sub.0+b.sub.1+b.sub.2+ . . .
+b.sub.k, 2) b.sub.PG2=mod(b.sub.k+1+b.sub.k+2+ . . . +b.sub.2k, 2)
b.sub.PG3=mod(b.sub.2k+1+b.sub.2k+2+ . . . +b.sub.3k, 2) wherein
b.sub.0,b.sub.1,b.sub.2, . . . , b.sub.B.sub.MS.sub.-1 represent
the bits of the mobile station ID, wherein d.sub.(B-Bms-1),
d.sub.(B-Bms-1)-1, d.sub.(B-Bms-1)-2 represent bits of the
bandwidth size/priority indicator, wherein k=.left
brkt-bot.B.sub.MS/3.right brkt-bot., and wherein mod(.,2)
represents a bitwise XOR operation.
43. The method as set forth in claim 40, further comprising:
generating the plurality of parity bits using a hash function.
44. The method as set forth in claim 40, further comprising:
generating the plurality of parity bits using a cyclic redundancy
check (CRC) generator.
.Iadd.45. A mobile station for use in a wireless communication
network, the mobile station comprising: a processor configured to:
group a plurality of bits of a B-bit quick access message into n
groups; determine a parity bit from each of the n groups, the n
parity bits corresponding to an index of a preamble sequence; and
generate a B-bit bandwidth request message based on the n parity
bits and a portion of the B bits of the quick access message; and
transceiver circuitry configured to transmit the B-bit bandwidth
request message to a base station. .Iaddend.
.Iadd.46. The mobile station as set forth in claim 45, wherein
B=16, n=3, and the B-bit bandwidth request message is:
b.sub.0,b.sub.1,b.sub.2, . . . ,
b.sub.12,b.sub.13,b.sub.14,b.sub.15=s.sub.0,s.sub.1,s.sub.2, . . .
, s.sub.12,d.sub.0,d.sub.1,d.sub.2, where b.sub.0,b.sub.1,b.sub.2,
. . . , b.sub.12,b.sub.13,b.sub.14,b.sub.15 are bits of the B-bit
bandwidth request message, s.sub.0,s.sub.1,s.sub.2, . . . ,
s.sub.12 are the portion of the B bits of the quick access message,
and d.sub.0,d.sub.1,d.sub.2 are the parity bits. .Iaddend.
.Iadd.47. The mobile station as set forth in claim 46, wherein the
parity bits are determined by:
p.sub.i=mod(s.sub.i+s.sub.i+3+s.sub.i+6+s.sub.i+9+s.sub.i+13, 2)
0.ltoreq.i<3, where
mod(s.sub.i+s.sub.i+3+s.sub.i+6+s.sub.i+9+s.sub.i+13, 2) represents
a bitwise XOR operation. .Iaddend.
.Iadd.48. The mobile station as set forth in claim 46, wherein bits
s.sub.0,s.sub.1,s.sub.2, . . . , s.sub.11 of the quick access
message represent a unique identifier of the mobile station and
bits s.sub.12, s.sub.13, s.sub.14, s.sub.15 of the quick access
message represent a type of message for which bandwidth is being
requested. .Iaddend.
.Iadd.49. The mobile station as set forth in claim 45, wherein the
mobile station is further configured to transmit the B-bit
bandwidth request message on a bandwidth request channel.
.Iaddend.
.Iadd.50. A base station for use in a wireless communication
network, the base station comprising: transceiver circuitry
configured to receive a B-bit bandwidth request message from a
mobile station, the B-bit bandwidth request message including a
preamble sequence and a quick access message; and a processor
configured to: determine a preamble index corresponding to the
received preamble sequence, the preamble index corresponding to n
parity bits; determine a (B-n) bit portion of the B-bit bandwidth
request message from the quick access message; group bits from the
(B-n) bit portion into n groups, each group having a substantially
equal number of bits; distribute the n parity bits to the n groups;
and recover the n bit portion of the B-bit bandwidth request
message using a bit-wise XOR operation on the bits in each of the n
groups. .Iaddend.
.Iadd.51. The base station as set forth in claim 50, wherein B=16,
n=3, and the B-bit bandwidth request message is:
b.sub.0,b.sub.1,b.sub.2, . . . ,
b.sub.12,b.sub.13,b.sub.14,b.sub.15=s.sub.0,s.sub.1,s.sub.2, . . .
s.sub.12, p.sub.0, p.sub.1, p.sub.2, where b.sub.0,b.sub.1,b.sub.2,
. . . , b.sub.12,b.sub.13,b.sub.14,b.sub.15 are bits of the B-bit
bandwidth request message, s.sub.0,s.sub.1,s.sub.2, . . . ,
s.sub.12 are the portion of the B bits of the quick access message,
and p.sub.0,p.sub.1,p.sub.2 are the parity bits. .Iaddend.
.Iadd.52. The base station as set forth in claim 51, wherein the
parity bits are determined by:
p.sub.i=mod(s.sub.i+s.sub.i+3+s.sub.i+6+s.sub.i+9+s.sub.i+13, 2)
0.ltoreq.i<3, where
mod(s.sub.i+s.sub.i+3+s.sub.i+6+s.sub.i+9+s.sub.i+13, 2) represents
a bitwise XOR operation. .Iaddend.
.Iadd.53. The base station as set forth in claim 51, wherein bits
s.sub.0, s.sub.1, s.sub.2, . . . , s.sub.11 of the quick access
message represent a unique identifier of the mobile station and
bits s.sub.12, s.sub.13, s.sub.14, s.sub.15 of the quick access
message represent a type of message for which bandwidth is being
requested. .Iaddend.
.Iadd.54. The base station as set forth in claim 50, wherein the
base station is configured to receive the B-bit bandwidth request
message from the mobile station on a bandwidth request channel.
.Iaddend.
.Iadd.55. For use in a mobile station in a wireless communication
network, a method comprising: grouping a plurality of bits of a
B-bit quick access message into n groups; determining a parity bit
from each of the n groups, the n parity bits corresponding to an
index of a preamble sequence; generating a B-bit bandwidth request
message based on the n parity bits and a portion of the B bits of
the quick access message; and transmitting the B-bit bandwidth
request message to a base station. .Iaddend.
.Iadd.56. The method as set forth in claim 55, wherein B=16, n=3,
and the B-bit bandwidth request message is:
b.sub.0,b.sub.1,b.sub.2, . . . ,
b.sub.12,b.sub.13,b.sub.14,b.sub.15=s.sub.0,s.sub.1,s.sub.2, . . .
, s.sub.12,d.sub.0,d.sub.1,d.sub.2, where b.sub.0,b.sub.1,b.sub.2,
. . . , b.sub.12,b.sub.13,b.sub.14,b.sub.15 are bits of the B-bit
bandwidth request message, s.sub.0,s.sub.1,s.sub.2, . . . ,
s.sub.12 are the portion of the B bits of the quick access message,
and d.sub.0,d.sub.1,d.sub.2 are the parity bits. .Iaddend.
.Iadd.57. The method as set forth in claim 56, wherein the parity
bits are determined by:
p.sub.i=mod(s.sub.i+s.sub.i+3+s.sub.i+6+s.sub.i+9+s.sub.i+13, 2)
0.ltoreq.i<3, where
mod(s.sub.i+s.sub.i+3+s.sub.i+6+s.sub.i+9+s.sub.i+13, 2) represents
a bitwise XOR operation. .Iaddend.
.Iadd.58. The method as set forth in claim 56, wherein bits
s.sub.0,s.sub.1,s.sub.2, . . . , s.sub.11 of the quick access
message sent a unique identifier of the mobile station and bits
s.sub.12,s.sub.13,s.sub.14,s.sub.15 of the quick access message
represent a type of message for which bandwidth is being requested.
.Iaddend.
.Iadd.59. The method as set forth in claim 55, wherein the B-bit
bandwidth request message is transmitted on a bandwidth request
channel. .Iaddend.
.Iadd.60. For use in a base station in a wireless communication
network, a method comprising: receiving a B-bit bandwidth request
message from a mobile station, the B-bit bandwidth request message
including a preamble sequence and a quick access message; and
determining a preamble index corresponding to the received preamble
sequence, the preamble index corresponding to n parity bits;
determining a (B-n) bit portion of the B-bit bandwidth request
message from the quick access message; grouping the (B-n) bits into
n groups, each group having a substantially equal number of bits;
distributing the n parity bits to the n groups; and recovering an
n-bit portion of the B-bit bandwidth request message using a
bit-wise XOR operation on the bits in each of the n groups.
.Iaddend.
.Iadd.61. The method as set forth in claim 60, wherein B=16, n=3,
and the B-bit bandwidth request message is:
b.sub.0,b.sub.1,b.sub.2, . . . ,
b.sub.12,b.sub.13,b.sub.14,b.sub.15=s.sub.0,s.sub.1,s.sub.2, . . .
, s.sub.12,p.sub.0,p.sub.1,p.sub.2, where b.sub.0,b.sub.1,b.sub.2,
. . . , b.sub.12,b.sub.13,b.sub.14,b.sub.15 are bits of the B-bit
bandwidth request message, s.sub.0,s.sub.1,s.sub.2, . . . ,
s.sub.12 are the portion of the B bits of the quick access message,
and p.sub.o,p.sub.1,p.sub.2 are the parity bits. .Iaddend.
.Iadd.62. The method as set forth in claim 61, wherein the parity
bits are determined by:
p.sub.i=mod(s.sub.i+s.sub.i+3+s.sub.i+6+s.sub.1+9+s.sub.i+13, 2)
0.ltoreq.i<3, where
mod(s.sub.i+s.sub.i+3+s.sub.i+6+s.sub.i+9+s.sub.i+13, 2) represents
a bitwise XOR operation. .Iaddend.
.Iadd.63. The method as set forth in claim 61, wherein bits
s.sub.0,s.sub.1,s.sub.2, . . . , s.sub.11 of the quick access
message represent a unique identifier of the mobile station and
bits s.sub.12,s.sub.13,s.sub.14,s.sub.15, of the quick access
message represent a type of message for which bandwidth is being
requested. .Iaddend.
.Iadd.64. The method as set forth in claim 60, wherein the B-bit
bandwidth request message is received from the mobile station on a
bandwidth request channel. .Iaddend.
Description
CROSS-REFERENCE TO RELATED APPLICATION(S) AND CLAIM OF PRIORITY
The present application is related to U.S. Provisional Patent
Application No. 61/270,897, filed Jul. 14, 2009, entitled "METHODS
TO INDEX THE PREAMBLES IN THE BANDWIDTH REQUEST CHANNEL".
Provisional Patent Application No. 61/270,897 is assigned to the
assignee of the present application and is hereby incorporated by
reference into the present application as if fully set forth
herein. The present application hereby claims priority under 35
U.S.C. .sctn.119(e) to U.S. Provisional Patent Application No.
61/270,897.
TECHNICAL FIELD OF THE INVENTION
The present application relates generally to wireless
communications and, more specifically, to indexing preamble
sequences in a bandwidth request channel between a mobile station
and base station.
BACKGROUND OF THE INVENTION
The IEEE 802.16m amendment allows a mobile station (MS) to transmit
bandwidth requests (BWREQ) to indicate to a base station (BS) that
it needs uplink (UL) bandwidth allocation. There are multiple
methods by which a mobile station can request bandwidth from the
base station. These methods include use of a contention based
random access based bandwidth request indicator, a standalone
bandwidth request, a piggybacked bandwidth request carried in an
extended header in the MAC PDU, and a bandwidth request using fast
feedback channel.
In the contention based random access method, multiple mobile
stations contend for a limited set of preamble sequences on a
common channel. The 802.16m standard defines 24 orthogonal access
sequences, or preamble sequences. Each mobile station may choose a
preamble sequence at random (out of the 24 possible preamble
sequences), and hope that no other mobile station chooses that
preamble sequence. If another mobile happens to choose the same
preamble sequence, then the two preamble sequences are said to have
collided at the BS.
SUMMARY OF THE INVENTION
For use in a wireless communication network, a mobile station
configured to determine a preamble sequence from a set of indexed
preamble sequences by generating an index of the preamble sequence
from a B-bit message is provided. The mobile station is configured
to group the B bits of the message into n groups, each group having
a substantially equal number of bits. The mobile station is also
configured to generate a parity bit from each of the n groups. The
mobile station is further configured to determine the index of the
preamble sequence based on then parity bits. The mobile station is
still further configured to transmit the preamble sequence
corresponding to the index of the preamble sequence.
For use in a wireless communication network, a base station
configured to process a B-bit message from a mobile station is
provided. The message includes a preamble sequence and a quick
access message. The base station is configured to receive the
message from the mobile station. The base station is also
configured to determine a preamble index corresponding to the
received preamble sequence, the preamble index corresponding to n
parity bits. The base station is also configured to determine a
(B-n) bit portion of the B bit message from the quick access
message. The base station is further configured to group the (B-n)
bits into n groups, each group having a substantially equal number
of bits. The base station is still further configured to distribute
the n parity bits to the n groups. The base station is also
configured to recover the n bit portion of the B bit message using
a bit-wise XOR operation on the bits in the each of the n
groups.
For use in a wireless communication network, a mobile station
configured to determine a preamble sequence from a set of indexed
preamble sequences by generating an index of the preamble sequence
from a message is provided. The message has B bits, B.sub.MS bits
of the B bits comprising a mobile station ID and (B-B.sub.MS) of
the B bits comprising a bandwidth indicator. The mobile station is
configured to generate a plurality of parity bits from the BMS
station ID bits. The mobile station is also configured to generate
a plurality of preamble bits from the plurality of parity bits. The
mobile station is further configured to replace a final plurality
of bits of the B-bit quick access message with the plurality of
preamble bits.
Before undertaking the DETAILED DESCRIPTION OF THE INVENTION below,
it may be advantageous to set forth definitions of certain words
and phrases used throughout this patent document: the terms
"include" and "comprise," as well as derivatives thereof, mean
inclusion without limitation; the term "or," is inclusive, meaning
and/or; the phrases "associated with" and "associated therewith,"
as well as derivatives thereof, may mean to include, be included
within, interconnect with, contain, be contained within, connect to
or with, couple to or with, be communicable with, cooperate with,
interleave, juxtapose, be proximate to, be bound to or with, have,
have a property of, or the like; and the term "controller" means
any device, system or part thereof that controls at least one
operation, such a device may be implemented in hardware, firmware
or software, or some combination of at least two of the same. It
should be noted that the functionality associated with any
particular controller may be centralized or distributed, whether
locally or remotely. Definitions for certain words and phrases are
provided throughout this patent document, those of ordinary skill
in the art should understand that in many, if not most instances,
such definitions apply to prior, as well as future uses of such
defined words and phrases.
BRIEF DESCRIPTION OF THE DRAWINGS
For a more complete understanding of the present disclosure and its
advantages, reference is now made to the following description
taken in conjunction with the accompanying drawings, in which like
reference numerals represent like parts:
FIG. 1 illustrates an exemplary wireless network according to one
embodiment of the present disclosure;
FIG. 2 illustrates a wireless mobile station according to
embodiments of the present disclosure;
FIG. 3 depicts a 5-step bandwidth request procedure for an IEEE
802.16m-compliant mobile station, according to embodiments of the
present disclosure;
FIG. 4 depicts a 3-step bandwidth request quick access procedure
for an IEEE 802.16m-compliant mobile station, according to
embodiments of the present disclosure;
FIG. 5 depicts a 3-step bandwidth request quick access procedure
that defaults to a 5-step bandwidth request procedure, according to
embodiments of the present disclosure;
FIG. 6 depicts a resource structure for the bandwidth request using
the OFDMA physical layer, for use with embodiments of the present
disclosure; and
FIG. 7 depicts a method for indexing preamble sequences, according
to an embodiment of the present disclosure.
DETAILED DESCRIPTION OF THE INVENTION
FIGS. 1 through 7, discussed below, and the various embodiments
used to describe the principles of the present disclosure in this
patent document are by way of illustration only and should not be
construed in any way to limit the scope of the disclosure. Those
skilled in the art will understand that the principles of the
present disclosure may be implemented
The following documents and standards descriptions are hereby
incorporated into the present disclosure as if fully set forth
herein:
IEEE C802.16m-09/0010r2, IEEE 802.16 Amendment Working Document,
Editor: Ron Murias, June 2009 (hereinafter the "0010r2" document);
and
IEEE C802.16m-08/0003r9a, IEEE 802.16m System Description Document,
Editor: Shkumbin Hamiti, June 2009 (hereinafter the "0003r9a"
document).
The embodiments of this disclosure provide methods to index
preamble sequences in a bandwidth request channel. The disclosed
embodiments are based on use of a contention based random access
based bandwidth request indicator. However, it will be understood
that other bandwidth request methods may be used with this
disclosure.
FIG. 1 illustrates an exemplary wireless network 100 according to
one embodiment of the present disclosure. In the illustrated
embodiment, wireless network 100 includes base station (BS) 101,
base station (BS) 102, and base station (BS) 103. Base station 101
communicates with base station 102 and base station 103. Base
station 101 also communicates with Internet protocol (IP) network
130, such as the Internet, a proprietary IP network, or other data
network.
Base station 102 provides wireless broadband access to network 130,
via base station 101, to a plurality of subscriber stations within
coverage area 120 of base station 102. The first plurality of
subscriber stations includes subscriber station (SS) 111,
subscriber station (SS) 112, subscriber station (SS) 113,
subscriber station (SS) 114, subscriber station (SS) 115 and
subscriber station (SS) 116. Subscriber stations 111-116 may be any
wireless communication device, such as, but not limited to, a
mobile phone, mobile PDA and any mobile station (MS). In an
exemplary embodiment, SS 111 may be located in a small business
(SB), SS 112 may be located in an enterprise (E), SS 113 may be
located in a WiFi hotspot (HS), SS 114 may be located in a
residence, and SS 115 and SS 116 may be mobile devices.
Base station 103 provides wireless broadband access to network 130,
via base station 101, to a plurality of subscriber stations within
coverage area 125 of base station 103. The plurality of subscriber
stations within coverage area 125 includes subscriber station 115
and subscriber station 116. In alternate embodiments, base stations
102 and 103 may be connected directly to the Internet by means of a
wired broadband connection, such as an optical fiber, DSL, cable or
T1/E1 line, rather than indirectly through base station 101.
In other embodiments, base station 101 may be in communication with
either fewer or more base stations. Furthermore, while only six
subscriber stations are shown in FIG. 1, it is understood that
wireless network 100 may provide wireless broadband access to more
than six subscriber stations. It is noted that subscriber station
115 and subscriber station 116 are on the edge of both coverage
area 120 and coverage area 125. Subscriber station 115 and
subscriber station 116 each communicate with both base station 102
and base station 103 and may be said to be cell-edge devices
interfering with each other. For example, the communications
between BS 102 and SS 116 may be interfering with the
communications between BS 103 and SS 115. Additionally, the
communications between BS 103 and SS 115 may be interfering with
the communications between BS 102 and SS 116.
Subscriber stations 111-116 may use the broadband access to network
130 to access voice, data, video, video teleconferencing, and/or
other broadband services. In an exemplary embodiment, one or more
of subscriber stations 111-116 may be associated with an access
point (AP) of a WiFi WLAN. Subscriber station 116 may be any of a
number of mobile devices, including a wireless-enabled laptop
computer, personal data assistant, notebook, handheld device, or
other wireless-enabled device. Subscriber station 114 may be, for
example, a wireless-enabled personal computer, a laptop computer, a
gateway, or another device.
Dotted lines show the approximate extents of coverage areas 120 and
125, which are shown as approximately circular for the purposes of
illustration and explanation only. It should be clearly understood
that the coverage areas associated with base stations, for example,
coverage areas 120 and 125, may have other shapes, including
irregular shapes, depending upon the configuration of the base
stations and variations in the radio environment associated with
natural and man-made obstructions.
Also, the coverage areas associated with base stations are not
constant over time and may be dynamic (expanding or contracting or
changing shape) based on changing transmission power levels of the
base station and/or the subscriber stations, weather conditions,
and other factors. In an embodiment, the radius of the coverage
areas of the base stations, for example, coverage areas 120 and 125
of base stations 102 and 103, may extend in the range from less
than 2 kilometers to about fifty kilometers from the base
stations.
As is well known in the art, a base station, such as base station
101, 102, or 103, may employ directional antennas to support a
plurality of sectors within the coverage area. In FIG. 1, base
stations 102 and 103 are depicted approximately in the center of
coverage areas 120 and 125, respectively. In other embodiments, the
use of directional antennas may locate the base station near the
edge of the coverage area, for example, at the point of a
cone-shaped or pear-shaped coverage area.
FIG. 2 illustrates a wireless mobile station 200 according to
embodiments of the present disclosure. In certain embodiments,
wireless mobile station 200 may represent any of the subscriber
stations 111-116 shown in FIG. 1. The embodiment of wireless mobile
station (MS) 200 illustrated in FIG. 2 is for illustration only.
Other embodiments of wireless mobile station 200 could be used
without departing from the scope of this disclosure.
Wireless mobile station 200 comprises antenna 205, radio frequency
(RF) transceiver 210, transmit (TX) processing circuitry 215,
microphone 220, and receive (RX) processing circuitry 225. Mobile
station 200 also comprises speaker 230, main processor 240,
input/output (I/O) interface (IF) 245, keypad 250, display 255,
memory 260, power manager 270, and battery 280.
Main processor 240 executes basic operating system (OS) program 261
stored in memory 260 in order to control the overall operation of
mobile station 200. In one such operation, main processor 240
controls the reception of forward channel signals and the
transmission of reverse channel signals by radio frequency (RF)
transceiver 210, receiver (RX) processing circuitry 225, and
transmitter (TX) processing circuitry 215, in accordance with
well-known principles.
Main processor 240 is capable of executing other processes and
programs resident in memory 260. Main processor 240 can move data
into or out of memory 260, as required by an executing process.
Main processor 240 is also coupled to I/O interface 245. The
operator of mobile station 200 uses keypad 250 to enter data into
mobile station 200. Alternate embodiments may use other types of
displays.
A mobile station may transmit bandwidth requests to indicate to a
base station that it needs uplink bandwidth allocation. There are
multiple methods by which a mobile station can request bandwidth
from the base station. These methods include use of a contention
based random access based bandwidth request indicator, a standalone
bandwidth request, a piggybacked bandwidth request carried in an
extended header in the MAC PDU, and a bandwidth request using fast
feedback channel.
Two procedures for requesting bandwidth using a contention based
random access based bandwidth request indicator are now described.
The two procedures, which may be supported concurrently, include a
5-step procedure and 3-step quick access procedure. The 5-step
procedure may be used independently or as a fallback mode for the
3-step quick access procedure in case of a failure in decoding the
quick access message.
FIG. 3 depicts a method incorporating the 5-step bandwidth request
procedure for an IEEE 802.16m-compliant mobile station, according
to one embodiment of the present disclosure. Method 300 is
described with respect to mobile station 200 and base station 102.
It is understood, however, that method 300 may be used with any
similarly-configured wireless device and base station.
First, mobile station 200 sends a bandwidth request indicator,
which is a preamble sequence selected randomly from the set of
preamble sequences, to base station 102 in the resource allocated
for a bandwidth request channel (step 301). A preamble sequence is
a sequence of numbers that belongs to a class of sequences that
have desirable properties like orthogonality or low correlation. In
the case of IEEE 802.16m, the preamble sequences are all
orthogonal.
Next, base station 102 provides a response to the bandwidth request
indicator (step 302). The response depends on the success or
failure of the decoding. If base station 102 successfully decodes
the bandwidth request indicator, it transmits a grant for uplink
transmission of the BW REQ header to mobile station 200.
Next, if mobile station 200 receives an uplink grant for the BW REQ
header from base station 102, then mobile station 200 transmits a
standalone bandwidth request message header to base station 102 in
the resource indicated by the uplink grant (step 303). However, if
mobile station 200 receives no uplink grant from base station 102,
then mobile station 200 considers the bandwidth request as failed
and may restart the procedure.
Next, on a successful decoding of the BW REQ header, base station
102 transmits an uplink grant to mobile station 200 (step 304).
However, if the decoding fails, base station 102 sends a negative
acknowledgement.
Next, assuming an uplink grant has been transmitted by base station
102, mobile station 200 transmits in the allocated resource
indicated in the uplink grant (step 305). Alternatively, on
receiving a negative acknowledgement, mobile station 200 considers
the bandwidth request as failed and may restart the procedure.
FIG. 4 depicts a method incorporating the 3-step bandwidth request
quick access procedure for an IEEE 802.16m-compliant mobile
station, according to one embodiment of the present disclosure.
Method 400 is described with respect to mobile station 200 and base
station 102. It is understood, however, that method 400 may be used
with any similarly-configured wireless device and base station.
First, mobile station 200 sends a bandwidth request indicator and a
quick access message to base station 102 in the resource allocated
for a bandwidth request channel (step 401). The quick access
message may include information to identify mobile station 200 and
also the type of the bandwidth request, including the size of the
bandwidth requested. A portion or all of the quick access message
is transmitted in the data portion of the BW REQ channel in
addition to the preamble sequence transmitted as the BW REQ
indicator. In some embodiments, the quick access message is a
16-bit message, including a 12-bit mobile station ID (STID) and a
4-bit bandwidth size/priority indicator (BWSize) (also sometimes
referred to as a flow ID). Quick access messages having more or
fewer bits are also possible.
Next, base station provides a response to the bandwidth request
indicator and quick access message (step 402). The response depends
on the success or failure of the decoding of both the preamble
sequence and the quick access message. If base station 102
successfully decodes the bandwidth request indicator and quick
access message, it transmits either an explicit acknowledgement
using a BW ACKA-MAP IE or a grant for uplink transmission to mobile
station 200. If base station 102 fails to decode the bandwidth
request indicator or the quick access message, then base station
102 transmits a BW ACK A-MAP IE indicating a negative
acknowledgement for the corresponding bandwidth request
opportunity.
Next, assuming an uplink grant has been transmitted by base station
102, mobile station 200 begins transmission of the bandwidth
request message (step 403). Alternatively, if mobile station 200
receives a negative acknowledgement indicating a quick access
message decoding failure (and an acknowledgement for bandwidth
request indicator decoding), or does not receive anything at all,
then mobile station 200 starts a bandwidth request timer, and the
BWREQ procedure defaults to a standard 5-step procedure, as seen in
FIG. 5. In FIG. 5, steps 501 and 502 correspond to steps 401 and
402 in FIG. 4. In step 503, mobile station 200 transmits a
standalone bandwidth request message header to base station
102.
If mobile station 200 receives an uplink grant using the default
5-step procedure, then mobile station 200 stops the timer.
Alternatively, if it receives a negative ACK or the bandwidth
request timer expires, then mobile station 200 considers the
bandwidth request as failed and may restart the procedure (step
504).
Next, assuming an uplink grant has been transmitted by base station
102, mobile station 200 transmits in the allocated resource
indicated in the uplink grant (step 505).
The 5-step bandwidth request procedure shown in FIG. 5 is a
fallback mode for the 3-step bandwidth request procedure shown in
FIG. 4. As illustrated in FIG. 5 in step 502, base station 102,
using the CDMA ALLOCATION A-MAP IE, grants mobile station 200 an
allocation to transmit a standalone bandwidth request header.
The 3-step bandwidth request may be limited to only certain
time-critical and frequently used messages. Examples of such
time-critical and frequently used messages are: VoIP(AMR) full rate
packet; VolP(AMR) SID; MAC HO-REQ message; MAC signaling header
(bandwidth request header); RoHC header; and TCP ACK.
The messages listed above are not exhaustive but are exemplary of
the type of messages that can use the 3-step bandwidth request
procedure. One common feature of the messages listed above is a
computable message size. Thus, if the type of message for which
bandwidth is being requested is known, the amount of bandwidth that
must be granted for the mobile station to transmit that message is
also known.
FIG. 6 depicts a resource structure for the bandwidth request using
the OFDMA physical layer, for use with embodiments of the present
disclosure. In IEEE 802.16m, a bandwidth request channel is made up
of three distributed bandwidth request tiles, where each bandwidth
request tile is defined as six contiguous subcarriers by six OFDM
symbols as shown in FIG. 6. The basic concept of OFDMA and the
concept of a physical layer resource unit configuration in IEEE
802.16m are described in the "0010r2" and "0003r9a" documents.
Each bandwidth request tile includes preamble sequences
Pr.sub.o-Pr.sub.23 These are the preamble sequences for the
bandwidth request indicator. The quick access message code words
M.sub.0-M.sub.35 are distributed over all three bandwidth request
tiles. The physical layer OFDMA resource is designed to support
both the 3-step and 5-step bandwidth request procedures. A mobile
station transmits either the bandwidth request indicator only (in
the case of a 5-step bandwidth request) or both the bandwidth
request indicator and a quick access message (in the case of a
3-step bandwidth request procedure).
The bandwidth request indicator is an access sequence or preamble
sequence having a length of 24 bits. The 802.16m standard defines
24 orthogonal access sequences, each having a 24-bit length. If a
mobile station has a message type for which the 3-step bandwidth
request can be used, then the mobile station chooses one of the 24
sequences corresponding to the specific type. The mobile station
then transmits both the preamble sequence (as a bandwidth request
indicator) and the quick access message to the base station. To aid
efficient transmission, a portion of the quick access message may
be transmitted in the preamble index. Several embodiments are
described below that map a portion of the quick access message to
the preamble index.
Upon receipt of the bandwidth request indicator, the base station
decodes the bandwidth request indicator, then proceeds to detect
the quick access message. The quick access message is meant to be
coherently decoded. The channel estimates for coherent detection of
the quick access message are derived by using the detected
bandwidth request indicator sequence as the pilot sequence. The
design shown in FIG. 6 detailing the placement of bandwidth request
indicator and quick access message facilitates such channel
estimation and coherent decoding.
The quick access message may consist of a sequence of B bits that
contains: (1) a sequence of bits uniquely identifying the mobile
station, and (2) the type of message for which the bandwidth is
being requested. The type of message may include: (1) the priority
for the message, (2) the flow ID of the message, and/or (3) a
predefined message type. In an example of such an arrangement, a
quick access message may contain a 12 bit MSID followed by a 4 bit
message type, thus giving the quick access message a total of 16
bits. Therefore, given that a part of the quick access message is
transmitted in the data portion of the BWREQ channel, the remaining
bits can be identified using the preamble index.
One way to identify the remaining bits using the preamble index is
to define a one-to-one mapping between the type of message and the
bandwidth request indicator preamble sequence. As an example,
assume VOIP(AMR) full rate packet is message type 1 and is mapped
to preamble index 1. Upon receiving the preamble index 1, the base
station knows that the bandwidth size requested is for a VOIP(AMR)
full rate packet. The base station uses the preamble sequence to
estimate the channel in each tile and then uses the channel
estimate to coherently decode the quick access message, which
contains the mobile station ID (STIR). On successful decoding of
the quick access message, the base station can grant uplink
bandwidth to the mobile station requesting to send the VOIP(AMR)
full rate packet.
While such a one-to-one mapping solves the problem of indicating
the BWREQ size for a 3-step bandwidth request procedure, it may not
be an efficient one. For example, if more than two users are
requesting bandwidth for the same VOIP (AMR) full rate packet, the
base station, while being able to resolve the BWREQ size, may not
be able to estimate the channel from each user to the base station,
and consequently cannot decode the quick access message. As a
result, a collision between multiple mobile users may occur.
Using the embodiments described below, collisions can be mitigated
for cases where more than one user uses bandwidth request for the
same service. The disclosed embodiments provide various solutions
where mapping of the preamble index depends not just on the BWREQ
size, but also on the mobile station-specific STID.
In the following embodiments, methods for mapping the B bits of the
quick access message for the 3-step BWREQ message are described.
The BWREQ message includes B.sub.MS bits of the STID and the
remaining (B-B.sub.MS) bits indicating bandwidth request size in
the preamble index. For ease of explanation, bits
b.sub.0,b.sub.1,b.sub.2, . . . , b.sub.B.sub.MS.sub.-1 are defined
as the unique STID associated with the mobile station. The
remaining bits d.sub.0,d.sub.1,d.sub.2, . . . ,
d.sub.(B-B.sub.MS.sub.-1) are defined as the bandwidth
size/priority indicator (BWSize). These bits are used to generate a
3-bit index p.sub.0,p.sub.1,p.sub.2, as described below. The
decimal equivalent of the binary 3-bit index points to the index of
the preamble sequence transmitted. A portion of the bits containing
the station ID as well as the BWSize forms the quick access
message. The preamble sequence and the quick access message are
then transmitted to the base station in the bandwidth request
channel. The base station extracts the preamble index from the
preamble sequence and the bits are decoded from the quick access
message. Both the preamble index and the quick access message bits
are used to reconstruct both the STID and BWSize at the base
station.
In one embodiment, bits b.sub.0,b.sub.1,b.sub.2, . . . ,
b.sub.B.sub.MS-1 are grouped into 3 groups, where each group
contains k=.left brkt-bot.B.sub.MS/3.right brkt-bot. bits. A parity
bit is generated for each of the 3 groups, and the preamble index
(the decimal equivalent of the bits) is generated as shown
below:
.function..ltoreq..ltoreq. ##EQU00001##
As an example, assume the quick access message is configured as a
set of 16 bits, s.sub.0,s.sub.1,s.sub.2, . . . , s.sub.15. Further
assume the STID is 12 bits (indicated as b.sub.0,b.sub.1,b.sub.2, .
. . ,b.sub.11) and the BWSize is 4 bits (indicated as
d.sub.0,d.sub.1,d.sub.2,d.sub.3). Then the 3 bits whose decimal
equivalent forms the preamble index are defined as shown below:
p.sub.i=mod(b.sub.1+b.sub.i+3+b.sub.i+6+b.sub.i+9d.sub.i+1, 2)
0.ltoreq.i.ltoreq.3 where mod is the modulo operator (bit wise XOR
operation). The bits b.sub.0,b.sub.1,b.sub.2, . . . , b.sub.11,
d.sub.0 are carried in the data portion of the BWREQ tile.
A mapping is defined between the quick access message and the
data+preamble sequence portion of the message as shown below. Let
b.sub.0,b.sub.1,b.sub.2, . . . , b.sub.12 be the bits carried in
the data portion of the BWREQ tile and b.sub.13,b.sub.14,b.sub.15
be the bits that indicate the preamble index. Then,
b.sub.0,b.sub.1,b.sub.2, . . .
,b.sub.12,b.sub.13,b.sub.14,b.sub.15=s.sub.0,s.sub.1,s.sub.2, . . .
,s.sub.12, p.sub.0,p.sub.1,p.sub.2 where p.sub.i=mod
(s.sub.i+s.sub.i+3+s.sub.i+6+s.sub.i+9+s.sub.i+13, 2)
0.ltoreq.i.ltoreq.3
When a base station receives the BWREQ message from the mobile
station, it processes the message. For example, the base station
determines the preamble index corresponding to the received
preamble sequence in the BWREQ message. The preamble index
corresponds to the 3 parity bits. The base station then determines
a 13-bit portion of the BWREQ message from the quick access
message. The base station groups the 13 bits into 3 groups, each
group having a substantially equal number of bits. The base station
then distributes the 3 parity bits to the 3 groups. The base
station then recovers the 3-bit portion of the 16-bit message using
a bit-wise XOR operation on the bits in the each of the 3
groups.
In another example, the quick access message is configured as a set
of 15 bits, s.sub.0,s.sub.1,s.sub.2, . . . , s.sub.14, where the
bit string is composed of 12 bit STID and a 3 bit BWSize. A mapping
is defined between the quick access message and the data+preamble
sequence portion of the message as shown below. Let
b.sub.0,b.sub.1,b.sub.2, . . . , b.sub.11 be the bits carried in
the data portion of the BWREQ tile and b.sub.12,b.sub.13,b.sub.14
be the bits that indicate the preamble index. Then:
b.sub.0,b.sub.1,b.sub.2, . . . ,
b.sub.11,b.sub.12,b.sub.13,b.sub.14=s.sub.0,s.sub.1,s.sub.2, . . .
s.sub.11, p.sub.0,p.sub.1,p.sub.2 where
p.sub.i=mod(s.sub.i+s.sub.i+3+s.sub.i+6+s.sub.i+9+s.sub.i+12,2)
0.ltoreq.i.ltoreq.3
In another embodiment of the present disclosure, bits
b.sub.0,b.sub.1, b.sub.2, . . . , b.sub.B.sub.MS.sub.-1 are grouped
into 3 groups, with each group containing k=.left
brkt-bot.B.sub.MS/3.right brkt-bot. bits. A parity bit is defined
for each of the 3 groups. The 3 parity bits b.sub.PG1, b.sub.PG2,
b.sub.PG3 are defined as shown below:
b.sub.PG1=mod(b.sub.0+b.sub.1+b.sub.2+ . . . +b.sub.k, 2)
b.sub.PG2=mod(b.sub.k+1+b.sub.k+2+ . . . +b.sub.2k, 2)
b.sub.PG3=mod(b.sub.2k+1+b.sub.2k+2+ . . . +b.sub.3k, 2)
However, in this embodiment, the 3 parity bits do not simply become
the 3 bits of the preamble index. Instead, the preamble index bits
p.sub.0, p.sub.1, p.sub.2 are mapped as shown below: Preamble Index
p.sub.0=mod(d.sub.(B-Bms-1)-2+b.sub.PG1, 2) Preamble Index
p.sub.1=mod(d.sub.(B-Bms-1)-1+b.sub.PG2, 2) Preamble Index
p.sub.2=mod(d.sub.(B-Bms-1)+b.sub.PG3, 2).
Several other embodiments follow. One of the benefits of all of the
following embodiments is that they may reduce and/or avoid the
chances of collisions where more than one user requests the same
service.
In another embodiment of the present disclosure, the STID bit
sequence b.sub.0,b.sub.1,b.sub.2, . . . , b.sub.B.sub.MS.sub.-1 is
first randomized using a randomizer function .pi.(.) that permutes
the indices of the bit sequence. In order to decode the randomizer
function, .pi.(.) must be known to both the mobile station as well
as the base station. In the art, the randomizer .pi.(.) is also
known as an interleaver. Let the sequence b.sub.0',b.sub.1', . . .
,b.sub.B.sub.MS.sub.-1'=.pi.(b.sub.0, b.sub.1, . . . ,
b.sub.B.sub.MS.sub.-1) be the randomized bit sequence. The 3 parity
bits can then be generated as described in the preceding
embodiment. First, the randomized bits b.sub.0',b.sub.1', . . . ,
b.sub.B.sub.MS.sub.-1' are grouped into 3 groups, with each group
containing k=.left brkt-bot.B.sub.MS/3.right brkt-bot. bits. Then,
a parity bit is defined for each of the 3 groups. The 3 parity bits
bp(v, bPG2, bp(13 are defined as shown below:
b.sub.PG1=mod(b.sub.0'+b.sub.1'+ . . . +b.sub.k', 2)
b.sub.PG2=mod(b.sub.k+1'+b.sub.k+2'+ . . . +b.sub.2k', 2)
b.sub.PG2=mod(b.sub.2k+1+'b.sub.2k+2'+ . . . +b.sub.2k', 2).
Then, the preamble index bits p.sub.0, p.sub.1, p.sub.2 are mapped
as shown below: Preamble Index
p.sub.0=mod(d.sub.(B-Bms-1)-2+b.sub.PG1, 2) Preamble Index
p.sub.1=mod(d.sub.(B-Bms-1)-1+b.sub.PG2, 2) Preamble Index
p.sub.2=mod(d.sub.(B-Bms-1)+b.sub.PG3, 2).
FIG. 7 depicts a method for indexing preamble sequences, according
to another embodiment of the present disclosure. As shown in FIG.
7, a 3 bit cyclic redundancy check (CRC) is generated from the
E.sub.MS bits of the STID. A bit wise XOR operation (modulo 2
addition) is used to add the 3 bit CRC with the 3 bit BWSize
indicator to generate the preamble indices p.sub.0, p.sub.1 and
p.sub.2.
In another embodiment of the present disclosure, the STID bits
b.sub.0,b.sub.1,b.sub.2, . . . , b.sub.B.sub.MS.sub.-1 are mapped
into three parity bits b.sub.PG1, b.sub.PG2, b.sub.PG3 using a hash
function. The hash value HV is the decimal result of the modulo 3
operation on the STID value as described in the equation below:
.times..times..times..times. ##EQU00002##
Next, the bits b.sub.PG1, b.sub.PG2, b.sub.PG3 are defined as the
binary equivalent of the decimal value HV. The preamble index bits
p.sub.0, p.sub.1, p.sub.2 are then mapped as shown below: Preamble
Index p.sub.0=mod(d.sub.(B-Bms-1)=2+b.sub.PG1, 2) Preamble Index
p.sub.1=mod(d.sub.(B-Bms-1)-1+b.sub.PG2, 2) Preamble Index
p.sub.2=mod(d.sub.(B-Bms-1)+b.sub.PG3, 2) where mod is the modulo
operator.
In another embodiment of the present disclosure, the three bits of
the preamble index are derived by concatenating x bits from the
B.sub.MS bits of the STID and the remaining (3-x) bits from the 3
bit BWSize. As an example, assume the quick access message is
configured as a set of 16 bits, s.sub.0,s.sub.1,s.sub.2, . . .
,s.sub.15, where the bit string is composed of STID and BWSize. A
mapping is defined between the quick access message and the
data+preamble sequence portion of the message as follows: Let
b.sub.0,b.sub.1,b.sub.2, . . . , b.sub.12 be the bits carried in
the data portion of the BWREQ tile and b.sub.13,b.sub.14,b.sub.15
be the bits that indicate the preamble index. Then:
b.sub.0,b.sub.1,b.sub.2, . . .
,b.sub.12,b.sub.13,b.sub.14,b.sub.15=s.sub.0,s.sub.1,s.sub.2, . . .
,s.sub.10,s.sub.13,s.sub.14,s.sub.15,s.sub.11,s.sub.12 Thus, this
method moves some of the bits of the STID toward the end of the
quick access message.
In another embodiment of the present disclosure, if a STID is
assigned to a mobile station incrementally, starting from the least
significant bit (LSB), in certain cases some of the most
significant bits (MSB) bits of STID may be zero. For example, for a
femtocell base station whose coverage may only have a few mobile
stations, then only the assigned LSB bits may be used to generate
the three bits index. If only 3 LSB bits b.sub.0, b.sub.1, b.sub.2
are assigned values, then the preamble index bits may be mapped as
shown below: p.sub.0=b.sub.0, p.sub.1=b.sub.1, p.sub.2=b.sub.2,
or
p=n(b.sub.0b.sub.1b.sub.2) where .pi.(.) is a randomization
function.
In some embodiments, various functions described above are
implemented or supported by a computer program that is formed from
computer readable program code and that is embodied in a computer
readable medium. The phrase "computer readable program code"
includes any type of computer code, including source code, object
code, and executable code. The phrase "computer readable medium"
includes any type of medium capable of being accessed by a
computer, such as read only memory (ROM), random access memory
(RAM), a hard disk drive, a compact disc (CD), a digital video disc
(DVD), or any other type of memory.
Although the present disclosure has been described with an
exemplary embodiment, various changes and modifications may be
suggested to one skilled in the art. It is intended that the
present disclosure encompass such changes and modifications as fall
within the scope of the appended claims.
* * * * *
References