Thread,
A possible fly in the Cisco ointment?
?October 26, 1999 ?
TI, Broadcom Back
Cisco VOFDM Coalition
By Loring Wirbel, EE Times
CISCO SYSTEMS on Tuesday announced an industry coalition to support the use of vector-based orthogonal frequency division multiplexing (VOFDM) for broadband wireless access.
The effort includes Bechtel Telecommunications, Electronic Data Systems, KPMG, LCC International, Motorola, Pace Micro Technology, Samsung Electronics, and Toshiba, as well as commitments from Broadcom and Texas Instruments to provide mixed-signal Application Specific Integrated Circuits (ASICs) for the advanced modulation scheme.
OFDM technologies have found increasing favor in realms as diverse as wireless LANs and third-generation (3G) cellular phones. Cisco's vector version of the modulation scheme will allow multiplexing of time-division and packet traffic in wireless broadband networks using such frequencies as the U-NII 5-GHz band defined by the Federal Communications Commission and the 28-GHz bands used for LMDS. The VOFDM proposal being promoted by the companies specifies that customer premises equipment will utilize a Layer 2 MAC (Media Access Control) technology similar to that employed for Ethernet packet standards.
Gregg Lowe, vice president of worldwide ASICs at Texas Instruments, said his company had been working with Cisco for two years on ASIC implementations of a MAC and physical-layer interface for VOFDM.
The use of OFDM could prove problematic, however. Wi-LAN, a small Canadian company that pioneered OFDM's use in wireless local loops and licensed OFDM algorithms for the IEEE's 802.11b wireless LAN working group, has indicated it will take an aggressive approach to intellectual property protection. Wi-LAN recently approached the International Telecommunications Union (ITU) with a proposal for licensing the Wi-LAN patent 5,555,268, saying that several 3G concepts being considered by ITU could infringe on the company's patent for multicode direct sequence spread spectrum.
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