IEEE Transactions on Communications · 2001 · 109 citations · 31 references
EngineeringCommunicationElectrical EngineeringChannel ManagementDigital CommunicationWireless CommunicationsBeamformingDigital Signal ProcessingInterference ManagementMultiple Access TechniquesPower ControlPower OptimizationFilter DesignInterference SuppressionMultiuser CommunicationMultiuser DetectionOptimal Power ControlSpatial Filter DesignTemporal FilteringTransmit Power Control
Third‑generation systems require high‑capacity flexible services, and CDMA is a promising candidate, but its interference‑limited nature necessitates interference management through power control, multiuser detection, and beamforming. This study investigates how combining power control with intelligent temporal and spatial receiver filter design can increase CDMA capacity. The authors derive signal‑to‑interference‑ratio maximizing joint temporal‑spatial receiver filters for unconstrained and constrained spaces and propose two‑step iterative power‑control algorithms that converge to optimal powers and filters, including a simpler filter‑update variant. Filtering in both temporal and spatial domains yields significant total transmit‑power savings compared with conventional power control or joint optimization in only one domain.
Among the ambitious challenges to be met by the third-generation systems is to provide high-capacity flexible services. Code-division multiple access (CDMA) emerges as a promising candidate to meet these challenges. It is well known that CDMA systems are interference-limited, and interference management is needed to maximally utilize the potential gains of this access scheme. Several methods of controlling and/or suppressing the interference through power control, multiuser detection (temporal filtering), and receiver beamforming (spatial filtering) have been proposed to increase the capacity of CDMA systems up to date. We investigate the capacity increase that is possible by combining power control with intelligent temporal and spatial receiver filter design. The signal-to-interference ratio maximizing joint temporal-spatial receiver filters in unconstrained and constrained filter spaces are derived. Two-step iterative power control algorithms that converge to the optimum powers and the joint temporal and spatial receiver filters in the corresponding filter domains are given. A power control algorithm with a less complex filter update procedure is also given. We observe that significant savings in total transmit power are possible if filtering in both domains is utilized compared with conventional power control and joint optimal power control and filtering in only one domain.
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