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Attaining >75% Acceptance: A Potential Consensus Solution for IEEE 802.11g. Bill Carney, Chris Heegard, Ph.D. & Sean Coffey, Ph.D. Texas Instruments Wireless Networking Business 141 Stony Circle, Suite 210 Santa Rosa California 95401 (707) 521-3060. Overview. Context
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Attaining >75% Acceptance:A Potential Consensus Solution for IEEE 802.11g Bill Carney, Chris Heegard, Ph.D. & Sean Coffey, Ph.D. Texas Instruments Wireless Networking Business 141 Stony Circle, Suite 210 Santa Rosa California 95401 (707) 521-3060 B.Carney, et. al. - Texas Instruments, Inc.
Overview • Context • Potential Solution for IEEE 802.11g • CCK/OFDM with PBCC • Potential IEEE 802.11g rates (Tx / Rx) • Interoperability • Implications • Satisfying the PAR • Conclusions B.Carney, et. al. - Texas Instruments, Inc.
Context • This is not a proposal; there is only one proposal remaining at this point: CCK/OFDM • This IS a potential solution for consideration now by members to attain the 75% consensus necessary to satisfy the selection procedure and go to Letter Ballot for 802.11g, if the final called-for vote demonstrates the remaining proposal does not have such support among the members • Standards invariably require technical compromise at some point; TGg is in need of compromise now B.Carney, et. al. - Texas Instruments, Inc.
Potential Consensus Solution for IEEE 802.11g • Both CCK/OFDM and PBCC transmitters are mandatory • Mandatory rates: • CCK/OFDM - 6, 12, 24 Mbps • PBCC - 5.5, 11, 22 Mbps • Must implement one of either CCK/OFDM or PBCC receiver; or both • Systems with either receiver can interoperate • With 11b networks via CCK • Within and between each other via new high rate modes • IEEE 802.11b backwards compatible • Short Preamble utilized • This potential solution would satisfy all aspects of PAR B.Carney, et. al. - Texas Instruments, Inc.
IEEE 802.11g Rates (Tx / Rx) • Barker • 1, 2 Mbps (mandatory / mandatory) • CCK • 5.5, 11 Mbps (mandatory / mandatory) • CCK/OFDM • 6, 12, 24 Mbps (mandatory / optional) • 9, 18, 36, 48, 54 Mbps (optional / optional) • PBCC • 5.5, 11, 22 Mbps (mandatory / optional) • 8.25, 16.5, 33 Mbps (optional / optional) B.Carney, et. al. - Texas Instruments, Inc.
The Transmitting Station Always Sends What the Receiving Station Can Decode • 802.11g system transmits to CCK-OFDM receiver using CCK-OFDM encoding • 802.11g system transmits to PBCC receiver using PBCC encoding B.Carney, et. al. - Texas Instruments, Inc.
Interoperability • Potential IEEE 802.11g compliant devices under this solution can talk to IEEE 802.11b compliant devices via CCK and Barker • Two high rate 802.11g compliant devices can always correspond at a new higher rate >20 Mbps • At higher rates, under 802.11g compliance, the transmitting station always sends what the receiving station can decode B.Carney, et. al. - Texas Instruments, Inc.
Implications • CCK/OFDM proponents would have to build a PBCC transmitter to be IEEE 802.11g compliant • Straightforward to add PBCC (<5K gates) to a CCK transmitter • Not known if existing CCK/ODFM silicon would require re-spin • PBCC proponents would have to build a CCK-OFDM transmitter to be IEEE 802.11g compliant • Design time/effort necessary to engineer the implementation • Re-spin required for existing PBCC-22 devices • Allows all parties to focus on their unique value add • Transmitters are the less complicated part of a solution • Receiver implementation allows for individual innovation • The industry can achieve consensus and move forward with clear development and deployment actions B.Carney, et. al. - Texas Instruments, Inc.
What about the PAR? • This potential consensus solution complies with all aspects of the TGg PAR • The PAR requires the largest mandatory rate >20Mbps • All potential IEEE 802.11g devices can communicate above 20 Mbps • Nothing specified about mandatory receiver requirements B.Carney, et. al. - Texas Instruments, Inc.
Example Standards • Many similar examples draw upon other standards where strong technical contention was evident • V.34/v.90/(v.92) • 3 trellis encoders required, 1 decoder required • Compromise struck because of different views of the complexity & performance trade-offs at the time • ADSL • Reed-Solomon and Trellis encoder required, either decoder • Compromise allowing interleaved and fast datapath was struck because of IP uncertainty for interleaved method at the time • HDSL-2 • Programmable binary convolutional encoder required • Compromise struck because multiple, valid encoding approaches were contending for inclusion or future consideration B.Carney, et. al. - Texas Instruments, Inc.
Conclusions • This solution is biased towards no particular technology • Both CCK/OFDM and PBCC become part of the new standard • Equalizes market entry position w.r.t. the availability of IEEE 802.11g compliant products • Encourages competition; keeps market growing • The purpose of an IEEE 802 standard is to write technical specifications that allow for superior networking solutions that interoperate and provide legacy support • Best of all new operational modes assured • Assures 802.11g devices are able to communicate effectively with growing base of 802.11b-compliant PBCC-5.5/11 Mbps products • This potential consensus solution will provide the opportunity to allow the industry to move forward rapidly with a known direction B.Carney, et. al. - Texas Instruments, Inc.
