Uplink interference analysis of LMDS networks applying CDMA with interference cancellation

Local multipoint distribution service (LMDS) is an emerging technology among broadband point-to-multipoint (PMP) wireless networks. The most critical point in designing LMDS networks is interference. Dominant access methods are FDMA and TDMA in LMDS, whereas CDMA has received less attention. Our aim is to demonstrate the feasibility of applying CDMA in LMDS networks by exploiting the results of research activities in CDMA interference suppression (e.g. multiuser detection). The uplink is the bottleneck of cellular PMP networks in terms of interference. Therefore, we analyze uplink interference in CDMA-based LMDS networks. Frequency-sectorized TDMA uplink interference scenarios are compared to those of CDMA using single user detector (matched filter) and multiuser detection algorithms, i.e. parallel interference cancellation (PIC) and successive interference cancellation (SIC). Uplink investigations of an LMDS sector are presented by carrier-to-interference ratio (C/I) maps and BER versus SNR simulations.