Solving the Near-Far Problem: Exploitation of Spatial and Spectral Diversity in Wireless Personal Communication Networks
A general approach is presented for overcoming the near-far power management problem in wireless communication networks, by exploiting the spatial or spectral diversity inherent to the communication network. It is shown that the stability and efficiency of near-far power management strategies used in CDMA, TDMA, or FDMA communication networks are greatly enhanced by exploiting the spatial diversity of the communication network. It is also shown that the same improvements in stability and efficiency can be obtained by exploiting the spectral diversity of CDMA networks. In particular, it is shown that use of on M-element multiport antenna array at the base station of any communication network can increase the frequency reuse of the network by a factor of M and greatly broaden the range of input SINRs required for adequate demodulation of the subscriber signals in the network. A similar result is obtained for CDMA networks employing an M-chip modulation on symbol (MOS) DSSS spreading formats where the code sequence repeats once per message symbol, even if a single antenna is used at the base stations in the network. These results are supported via computer simulations for an FDMA network employing a 3-element antenna array to separate 3 AMPS-type FM signals received at the same frequency, and for a CDMA communication network employing a single-antenna optimal linear despreader to separate 32 users with 64-chip MOS-DSSS modulation formats.
KeywordsCoherence Autocorrelation Azimuth Imino Limax
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