SWL timing synchronization algorithm effectiveness in preserving spreading gain when multiple simultaneous terminals use the same spreading code
Garret T. Okamoto, Shiann‐Shiun Jeng, Guanghan Xu · Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · 1999
The Smart Wireless LAN (SWL) system integrates the Space- Division-Multiple-Access technique (also called smart antennas) with spread spectrum wireless LAN systems, such as IEEE 802.11 systems, to enable multiple wireless LAN users to transmit simultaneously in a frequency band. This advantage creates a potential problem because the 802.11 standard requires that all terminals use the same spreading code, so a straightforward application of the 802.11 standard could result in the loss of the 10 dB of spreading gain achieved by each terminal. This isn't a problem in a conventional system where only one user may transmit at a time in a frequency band, so the solution to this problem was created specifically for the SWL system. The Timing Synchronization Algorithms studied in this paper enable multiple (up to 11) users to use the same spreading code without a loss of the spreading gain. Two complimentary algorithms, in their sorted and unsorted formats, are studied in this paper and their simulation results are analyzed.