SINR, power efficiency, and theoretical system capacity of parallel interference cancellation

Abstract

This paper analytically derives exact expressions for the SINR of the two-stage linear parallel interference cancellation (LPIC) and two-stage hard-decision parallel interference cancellation (HPIC) multiuser detectors in a synchronous, nonorthogonal, binary, CDMA communication system with deterministic short spreading sequences. We consider approximations to the SINR expressions that are justified in typical operating scenarios to obtain a more intuitive understanding of the SINR performance of the HPIC detector. We consider the case where a specific SINR requirement is given for each user in the system and derive expressions for the set of transmit powers necessary to meet this requirement when two-stage LPIC or HPIC detection is used. We also derive expressions for a measure of the theoretical system capacity using LPIC and HPIC detection, defined as the maximum number of users possible in a system with finite available transmit power.Numerical results are presented that compare the HPIC and LPIC detectors to the hard-decision successive interference cancellation (SIC) detector and matched filter (MF) detector. Our results suggest that HPIC detection may offer the best SINR and power efficiency performance when the number of users in the system is low to moderate and that SIC detection may offer superior performance when the number of users in the system is large.

Signal Processing by Generalized Receiver in DS-CDMA Wireless Communication Systems with Frequency-Selective Channels

“…Equation (6) shows that the MIMO system with beamforming can be modeled as an equivalent single-input multiple-output (SIMO) system. Therefore, the GR can use the same equalization, channel estimation, and channel tracking techniques as for a single antenna transmission.…”

“…During analysis we consider only the hypothesis H 1 -"a yes" signal in the input stochastic process. Then the equivalent received baseband signal for the kth diversity branch can be written in the form given by (4) and (6). For our convenience, rewrite the received signal in the following form:…”

“…If the power control is perfect, i.e., S u = S v = S and P BER e,u = P BER e , where P BER e is approximated by the BER of high SNR case, i.e., we have the Q N K−1 function [6,29], (108) can be rewritten as…”

Signal Processing by Generalized Receiver in DS-CDMA Wireless Communication Systems with Optimal Combining and Partial Cancellation

“…Now, let us compare (38) and (42) to obtain the closed form expression for the SER of M-ary PAM system employing the GR with quadrature subbranch HS/MRC and HS/MRC schemes. We can easily see that taking into account (14), (15), (35), (36), and (39), the SER of M-ary PAM system employing the GR with quadrature subbranch HS/MRC and HS/MRC schemes can be defined in the following form…”

“…and P e is approximated by the BER of high SNR case, that is, the Q( N/(K − 1)) function [35,36], (77) can be rewritten as…”