Yoni Perets

Pilot interference cancellation technology for CDMA cellular networks

This paper considers the link-level and network-level performance of code division multiple access (CDMA) pilot interference cancellation (pilot IC) technology, a low-complexity advanced receiver technology being considered for use in commercial third generation (3G) CDMA cellular systems. The concept behind this technology is to estimate and cancel at the handset receiver the interference effects associated with CDMA downlink pilot signals broadcast from the base stations of the network. The canceling of interference at the receiver improves the signal-to-interference/noise ratio (SINR), which enables increased cell capacity or throughput. In this paper, we derive SINR expressions for evaluating the probability of error performance of both the RAKE and pilot IC handset receivers, under conventional random spreading code assumptions. The approach can easily and accurately model a wide variety of transmitter, channel, and receiver conditions, including the effects of channel estimation. We also utilize radio network simulations to illustrate and quantify the capacity gains available for 3G CDMA networks through the use of pilot IC handsets. Network simulations are also used to examine the reduced level of soft-handoff found to be possible in pilot IC-based networks and the increased flexibility available in setting pilot power levels. We further consider the impact of using stronger pilot signals for improving the demodulation performance of sensitive higher-order modulation constellations that are needed to support spectrally efficient high-rate data services.

Cancellation accuracy in CDMA pilot interference cancellation

Pilot interference cancellation (IC) in mobile receivers has recently gained attention for CDMA cellular networks. In this paper we address the accuracy of the pilot interference cancellation at the receiver. In doing so, we consider the effects of channel estimation, timing estimation, receiver tap-spacing granularity, and the other receiver imperfections. The analytical and simulation results illustrate that high cancellation accuracy is feasible for the pilot IC receiver. These result indicate that the significant potential capacity gains reported in [3GPP TR 25.99, 2001, J.S. Sadowski et al., 2003] for pilot IC, are achievable under realistic receiver conditions.

Capacity gains from pilot cancellation in CDMA networks

Common pilot cancellation in mobile receivers has recently gained attention for CDMA cellular networks. This paper presents system simulation results showing that the network capacity gains achievable from both ideal and hardware resource limited pilot cancellation receivers are significant. We show that the highest gains are achievable from both ideal and hardware resource limited pilot cancellation receivers are significant. We show that the highest gains are achieved for networks populated with high rate data users, rather than voice users. We also pay special attention to the interaction between pilot cancellation and soft handoff in a power controlled network. We show that pilot cancellation allows the network to operate with fewer mobiles in soft handoff, hence reducing network signaling overhead and infrastructure costs.

BER performance of CDMA pilot interference cancellation receivers

Pilot interference cancellation (IC) has recently received consideration for use in third generation (3G) CDMA cellular receivers. In this paper, we derive an expression for evaluating the bit error rate (BER) performance of both the RAKE and pilot IC receivers, under conventional random spreading code assumptions. The approach can provide results for a wide variety of transmitter, channel, and receiver assumptions, and can easily take into account the effects of channel estimation, as used for determining the RAKE combining coefficients and for reconstructing pilot interference. The analytical results are compared to detailed link-level simulations of the 3G commercial wideband CDMA system developed by 3GPP, with excellent agreement found.