Design of a Baseband Transceiver for Multicarrier CDMA Communications

Abstract

Multicarrier systems have become popular for their spectral efficiency and robustness against frequency-selective fading. Multicarrier code-division multiple access (MC-CDMA) is a technique that combines the advantage of multicarrier modulation with that of code-division multiple access (CDMA) to offer reliable high-data-rate downlink cellular communication services. In this paper, we present the architecture of a downlink baseband transceiver using the MC-CDMA technology under the same bandwidth requirement and channel condition as the third-generation wideband CDMA system. In the transmitter, a scrambling code is applied in order to reduce the peak-to-average power ratio (PAPR) of the transmitter output. In the receiver, we use a joint weighted least-squares (WLS) synchronization error estimation algorithm and a novel channel estimator. Both algorithms greatly enhance the system error-rate performance, as indicated by functional simulation. Simulation results also verify maximum aggregate coded data rates of 5.4/10.8 Mbps from 32/64 users in mobile/stationary multipath fading channel with a 3/4 convolutional code, respectively

A 1.1-V 9.9-mW MC-CDMA Downlink Baseband Receiver IC for Next-Generation Cellular Communication Systems

“…The measurement results coincide with the fixed-point simulation results. Also the implementation loss due to quantization errors compared to floating-point simulation [1] is less than 0.5 dB when the symbol error rate is about 10 −5 with 32 active users, constellation of 16-QAM and a spreading factor of 64. …”

“…In Table I, we summarize several important parameters of the proposed MC-CDMA system [1]. The proposed system uses the same RF frequency, 2 GHz, and signal bandwidth, 5 MHz, as those of the 3G standards.…”

Hybrid Multi-carrier CDMA Modulation based on VLSI

“…Jing in Table I, we summarize several important parameters of the proposed MC-CDMA system [7], [8]. The proposed system uses the same RF frequency and signal bandwidth as those of the 3G standards, i.e., 2 GHz and 5 MHz, since its major goal is to increase the downlink data rate of the current 3G W-CDMA cellular communication system in urban areas.…”

A Low-Power Multicarrier-CDMA Downlink Baseband Receiver for Future Cellular Communication Systems

“…In Table I, we summarize several important parameters of the proposed MC-CDMA system [7], [8]. The proposed system uses the same RF frequency and signal bandwidth as those of the 3G standards, i.e., 2 GHz and 5 MHz, since its major goal is to increase the downlink data rate of the current 3G W-CDMA cellular communication system in urban areas.…”

“…In the receiver, a symbol timing detector, a carrier recovery loop, and a sampling clock recovery loop are integrated to deal with the synchronization issues. Owing to the precise synchronization requirements in the multi-carrier systems, rough acquisition which speeds up the loop convergence and subsequent tracking mechanism which enhances the accuracy are both implemented [7].…”