SGD Frequency-Domain Space-Frequency Semiblind Multiuser Receiver with an Adaptive Optimal Mixing Parameter

A novel stochastic gradient descent frequency-domain (FD) space-frequency (SF) semiblind multiuser receiver with an adaptive optimal mixing parameter is proposed to improve performance of FD semiblind multiuser receivers with a fixed mixing parameters and reduces computational complexity of suboptimal FD semiblind multiuser receivers in SFBC downlink MIMO MC-CDMA systems where various numbers of users exist. The receiver exploits an adaptive mixing parameter to mix information ratio between the training-based mode and the blind-based mode. Analytical results prove that the optimal mixing parameter value relies on power and number of active loaded users existing in the system. Computer simulation results show that when the mixing parameter is adapted closely to the optimal mixing parameter value, the performance of the receiver outperforms existing FD SF adaptive step-size (AS) LMS semiblind based with a fixed mixing parameter and conventional FD SF AS-LMS training-based multiuser receivers in the MSE, SER and signal to interference plus noise ratio in both static and dynamic environments

On the performance and capacity of space-time block coded multicarrier CDMA communication systems

Ph.DDOCTOR OF PHILOSOPH

Filter Bank Multicarrier for Massive MIMO

This paper introduces filter bank multicarrier (FBMC) as a potential candidate in the application of massive MIMO communication. It also points out the advantages of FBMC over OFDM (orthogonal frequency division multiplexing) in the application of massive MIMO. The absence of cyclic prefix in FBMC increases the bandwidth efficiency. In addition, FBMC allows carrier aggregation straightforwardly. Self-equalization, a property of FBMC in massive MIMO that is introduced in this paper, has the impact of reducing (i) complexity; (ii) sensitivity to carrier frequency offset (CFO); (iii) peak-to-average power ratio (PAPR); (iv) system latency; and (v) increasing bandwidth efficiency. The numerical results that corroborate these claims are presented.Comment: 7 pages, 6 figure

Near-Instantaneously Adaptive HSDPA-Style OFDM Versus MC-CDMA Transceivers for WIFI, WIMAX, and Next-Generation Cellular Systems

Burts-by-burst (BbB) adaptive high-speed downlink packet access (HSDPA) style multicarrier systems are reviewed, identifying their most critical design aspects. These systems exhibit numerous attractive features, rendering them eminently eligible for employment in next-generation wireless systems. It is argued that BbB-adaptive or symbol-by-symbol adaptive orthogonal frequency division multiplex (OFDM) modems counteract the near instantaneous channel quality variations and hence attain an increased throughput or robustness in comparison to their fixed-mode counterparts. Although they act quite differently, various diversity techniques, such as Rake receivers and space-time block coding (STBC) are also capable of mitigating the channel quality variations in their effort to reduce the bit error ratio (BER), provided that the individual antenna elements experience independent fading. By contrast, in the presence of correlated fading imposed by shadowing or time-variant multiuser interference, the benefits of space-time coding erode and it is unrealistic to expect that a fixed-mode space-time coded system remains capable of maintaining a near-constant BER

Optimal channel equalization for filterbank transceivers in presence of white noise

Filterbank transceivers are widely employed in data communication networks to cope with inter-symbol-interference (ISI) through the use of redundancies. This dissertation studies the design of the optimal channel equalizer for both time-invariant and time-varying channels, and wide-sense stationary (WSS) and possible non-stationary white noise processes. Channel equalization is investigated via the filterbank transceivers approach. All perfect reconstruction (PR) or zero-forcing (ZF) receiver filterbanks are parameterized in an affine form, which eliminate completely the ISI. The optimal channel equalizer is designed through minimization of the mean-squared-error (MSE) between the detected signals and the transmitted signals. Our main results show that the optimal channel equalizer has the form of state estimators, and is a modified Kalman filter. The results in this dissertation are applicable to discrete wavelet multitone (DWMT) systems, multirate transmultiplexers, orthogonal frequency division multiplexing (OFDM), and direct-sequence/spread-spectrum (DS/SS) based code division multiple access (CDMA) networks. Design algorithms for the optimal channel equalizers are developed for different channel models, and white noise processes, and simulation examples are worked out to illustrate the proposed design algorithms

Wavelet-based multi-carrier code division multiple access systems

EThOS - Electronic Theses Online ServiceGBUnited Kingdo

New adaptive transmission schemes for MC-CDMA systems.

by Yin-Man Lee.Thesis (M.Phil.)--Chinese University of Hong Kong, 1999.Includes bibliographical references (leaves 82-[87]).Abstracts in English and Chinese.Chapter 1 --- Introduction --- p.1Chapter 1.1 --- Overview of MC-CDMA --- p.1Chapter 1.2 --- System Model --- p.3Chapter 1.3 --- Receiver Optimization --- p.7Chapter 1.4 --- Transmitter Optimization --- p.9Chapter 1.5 --- Nonlinearly Constrained Optimization --- p.10Chapter 1.6 --- Outline of Thesis --- p.11Chapter 2 --- Centralized Transmitter Optimization for MC-CDMA Systems --- p.13Chapter 2.1 --- Introduction --- p.13Chapter 2.2 --- Problem Development --- p.15Chapter 2.3 --- Lagrangian Optimization Approaches --- p.16Chapter 2.3.1 --- Penalty Function Method --- p.17Chapter 2.3.2 --- Barrier Function Method --- p.19Chapter 2.3.3 --- Powell's Method and Augmented Lagrangian Method --- p.21Chapter 2.4 --- Optimal FDMA System --- p.23Chapter 2.5 --- Modified Centralized Optimization Schemes --- p.25Chapter 2.6 --- Performance --- p.27Chapter 2.6.1 --- Typical Behavior --- p.27Chapter 2.6.2 --- Average Performance --- p.32Chapter 2.7 --- Summary --- p.38Chapter 3 --- Decentralized Transmitter Optimization for MC-CDMA Sys- tems --- p.39Chapter 3.1 --- Introduction --- p.39Chapter 3.2 --- System Model --- p.41Chapter 3.3 --- Optimization --- p.42Chapter 3.3.1 --- Receiver Optimization --- p.43Chapter 3.3.2 --- Single-user Transmitter Optimization --- p.44Chapter 3.3.3 --- Decentralized Transmission Scheme --- p.45Chapter 3.3.4 --- Multirate Transmission with Decentralized Transmission Scheme --- p.47Chapter 3.4 --- Performance --- p.48Chapter 3.5 --- Summary --- p.57Chapter 4 --- Performance Evaluation of Various Adaptive Transmission Schemes --- p.59Chapter 4.1 --- Introduction --- p.59Chapter 4.2 --- Comparison of Different Adaptive Transmission Schemes --- p.61Chapter 4.3 --- Adaptive Transmission Schemes with K > M --- p.64Chapter 4.4 --- Modified Adaptive Transmission Scheme with Graceful Degrada- tion in the SNR --- p.68Chapter 4.5 --- Summary --- p.71Chapter 5 --- Conclusions and Future Work --- p.73Chapter 5.1 --- Conclusions --- p.73Chapter 5.2 --- Future Work --- p.75A The Hungarian Method for Optimal Frequency Assignment --- p.76Bibliography --- p.8