Multiplex communications – Channel assignment techniques – Carrier sense multiple access
Reexamination Certificate
2007-02-20
2007-02-20
Qureshi, Afsar (Department: 2616)
Multiplex communications
Channel assignment techniques
Carrier sense multiple access
C370S317000, C370S338000, C455S422100
Reexamination Certificate
active
10256516
ABSTRACT:
An access method for periodic contention-free sessions (PCFS) reduces interference between overlapping first and second wireless LAN cells contending for the same medium. Each cell includes a respective plurality of member stations and an access point (AP) station. The access method for periodic contention-free sessions (PCFS) includes a fixed cycle time that reduces conflicts with PCFS from other cells. The PCFS from several cells are repeated in cycles of cycle period (CP), which is the contention-free period (CFP) of an access point times a factor that is a function of the number of overlapping cells. Periodic contention-free sessions (PCFSs) are generated, one from each overlapping cell. PCFS transmission attempts occur at the fixed specified time spacing following the start of the previous cycle. Each active AP sets a timer at CP and a PCFS is initiated when the timer expires. The timer is then reset to CP and this starts a new cycle. Contention transmissions are attempted by stations based on their assigned priority. If a channel is busy at the designated start time for transmitting a PCFS, the PCFS is shortened by the time lost. Interleaving PCFSs and CFSs reduces conflicts with CFSs from other cells. To lessen the contention between APs of different cells, each station's Network Allocation Vector (NAV) and Inter-BSS Network Allocation Vector (IBNAV) is updated by an increased value of the next CFS length, the increment being the inter-BSS contention period (IBCP). APs will attempt to access the channel during the IBCP only for transmitting a PCFS, while they will wait for the NAV and IBNAV expirations before attempting to transmit a CFS. Interleaving PCFSs and CFSs also enables maintaining quality of service (QoS).
REFERENCES:
patent: 5142533 (1992-08-01), Crisler et al.
patent: 5185739 (1993-02-01), Spear
patent: 5329531 (1994-07-01), Diepstraten et al.
patent: 5353287 (1994-10-01), Kuddes et al.
patent: 5355375 (1994-10-01), Christensen
patent: 5416780 (1995-05-01), Patel
patent: 5636223 (1997-06-01), Reardon et al.
patent: 5644576 (1997-07-01), Bauchot et al.
patent: 5682381 (1997-10-01), Sekihata et al.
patent: 5768267 (1998-06-01), Raith et al.
patent: 5828663 (1998-10-01), Ikegami
patent: 5852405 (1998-12-01), Yoneda et al.
patent: 5852723 (1998-12-01), Kalkunte et al.
patent: 5892769 (1999-04-01), Lee
patent: 5987033 (1999-11-01), Beer et al.
patent: 5999818 (1999-12-01), Gilbert et al.
patent: 6011784 (2000-01-01), Brown et al.
patent: 6047175 (2000-04-01), Trompower
patent: 6055578 (2000-04-01), Williams et al.
patent: 6067291 (2000-05-01), Kamerman et al.
patent: 6078591 (2000-06-01), Kalkunte et al.
patent: 6272117 (2001-08-01), Choi et al.
patent: 6343071 (2002-01-01), Lansford
patent: 6418148 (2002-07-01), Kumar et al.
patent: 6434187 (2002-08-01), Beard et al.
patent: 6473414 (2002-10-01), Hartley et al.
patent: 6493331 (2002-12-01), Walton et al.
patent: 6614799 (2003-09-01), Gummalla et al.
patent: 6625162 (2003-09-01), Myojo et al.
patent: 6832093 (2004-12-01), Ranta
patent: 2002/0061031 (2002-05-01), Sugar et al.
patent: 2002/0152324 (2002-10-01), Sherman
patent: 2003/0013451 (2003-01-01), Walton
patent: 2003/0103521 (2003-06-01), Raphaeli
patent: 2003/0123405 (2003-07-01), Del Prado et al.
patent: 2003/0224787 (2003-12-01), Gandolfo
patent: 2004/0022219 (2004-02-01), Mangold et al.
patent: 2006/0041676 (2006-02-01), Sherman
patent: 0994604 (2000-04-01), None
patent: WO 03/039054 (2003-05-01), None
Bononi, L., Cont, M., and Gregori, E., “Design and Performance Evaluation of an Asymptotically Optimal Backoff Algorithm for IEEE 802.11 Wireless LANs”,Proceedings of the 33rdHawaii International Conference on System Sciences—2000, Jan. 4-7, 2000, pp. 1-10.
Deng, Dr-Jiunn and Chang, Ruay-Shiung, “A Priority Scheme for IEEE 802.11 DCF Access Method”,IEICE Trans. Commun., Jan. 1999, vol. E82-B., No. 1, pp. 96-102.
IEEE Std 802.11, “Local and Metropolitan Area Networks”, 1997, p. 92.
AT & T Corp.
Qureshi Afsar
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