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TGg Final Statement

TGg Final Statement. Jim Zyren Mark Webster Steve Halford Intersil Corporation. OFDM for IEEE 802.11g. CCK / OFDM Fully compliant with TGg requirements Backward compatible with IEEE 802.11b Utilizes 802.11a as a basis for the higher data rates

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TGg Final Statement

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  1. TGg Final Statement Jim Zyren Mark Webster Steve Halford Intersil Corporation J. Zyren, M. Webster, S. Halford, Intersil Corp

  2. OFDM for IEEE 802.11g • CCK / OFDM • Fully compliant with TGg requirements • Backward compatible with IEEE 802.11b • Utilizes 802.11a as a basis for the higher data rates • Data rates identical to 802.11a (6,9,12,18,24,36,48,54 Mbps) • Industry Convergence • OFDM already adopted for 802.11a & HiperLAN2 • Uses technology developed by MANY companies • Regulatory Issues • All TGg proposals require rule change • FCC is changing rules • Do we want to enable another hi rate technology? • Inevitable direct competition with OFDM @ 2.4 & 5 GHz J. Zyren, M. Webster, S. Halford, Intersil Corp

  3. Regulatory Status • None of the TGg proposals meets the FCC requirements for 2.4 GHz DSSS systems • FCC considers spectral efficiency to be a key component • Meeting processing gain or CW jammer test alone is not sufficient • FCC has compelling reasons to modify 2.4 GHz DSSS rules: • WiLan Application for Review • TI proposal for PBCC • Current proceeding (99-231) regarding DSSS testing • Consumer demand for higher data rates • FCC is planning to initiate a rule making process to change the rules for DSSS systems in the 2.4 GHz band • Expected to redefine “DSSS” to permit higher data rates • Likely initiated in the spring timeframe • OFDM is coming to the 2.4 GHz band J. Zyren, M. Webster, S. Halford, Intersil Corp

  4. Why OFDM for 2.4 GHz? • OFDM is a powerful and proven waveform • Selected for both 802.11a and HyperLan2 • Robust performance against multi-path, AWGN, and in-band interference • Real world performance impacts • Interleaving and error coding result in very robust performance • Data rates to 54 Mbps • Industry Convergence • Many companies are developing OFDM technology • Industry working to develop a single 5 GHz standard for the 5 GHz bands • 5 GHz IAG and IEEE 802.11 5GSG • Provide graceful migration path from 802.11b to 802.11a • CCK-OFDM offers forward & backward compatibility • OFDM is being widely adopted • TGg should capitalize on this development --- not resist it! J. Zyren, M. Webster, S. Halford, Intersil Corp

  5. Comparison of PBCC and OFDM • PBCC was adopted by IEEE 802.11 on the same day as CCK but no PBCC based products are on the market • Design complexity delays practical implementation • WLAN channels are limited by multi-path not AWGN • Convolutional codes emphasize AWGN performance but complicate receiver via complex equalization requirements • By comparison, CCK block codes are optimized for multi-path properties • Block codes are selected for autocorrelation and cross correlation properties • Lowers receiver complexity and speeds implementation • Similarly, OFDM characteristics are well suited to WLAN applications • Robust performance against multi-path, in-band interference and AWGN • Receiver scales to higher data rates with no increase in complexity • PBCC is more differentiated from CCK than OFDM • PBCC is not optimized to address real world WLAN effects • PBCC requires the use of an entirely different receiver structure J. Zyren, M. Webster, S. Halford, Intersil Corp

  6. Some Closing Thoughts • Single carrier systems do not scale well to higher data rates • Selection of PBCC will effectively cap data rates and require the standardization of yet another technology • TGg should adopt the fastest technology for the HI RATE EXTENSION • OFDM provides for data rates to 54 Mbps • Complements 802.11a • Speeds WLAN adoption in BOTH 2.4 & 5 GHz bands • OFDM will likely come into the band regardless of what the IEEE does • IEEE should standardize around OFDM • OFDM is the right choice for TGg J. Zyren, M. Webster, S. Halford, Intersil Corp

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