This paper presents the approach and algorithm of joint detection decoding with turbo codes for MIMO wireless communication systems. To the best of the authors' knowledge, this is the first proposed approach that can perform MIMO detection and decoding of turbo codes in a single stage. The detailed introduction of the proposed method and outline of the algorithm are given, while extensive simulations have been conducted to investigate the performance of the proposed algorithm. The simulation results show that, comparing to the conventional separate scheme, the proposed joint algorithm can achieve comparable BER performance with reduced hardware complexity and processing latency.

In this paper, a low-complexity integration-based (LCIB) maximum a prior probability (MAP) soft-in-soft-out (SISO) detector for channel coded MIMO-OFDM systems is developed. Our developed LCIB MAP SISO detector uses novel low-complexity integration algorithms to efficiently compute the extrinsic information of the conventional optimal MAP SISO detector. As the simulation results, the iterative detection and decoding (IDD) receiver with our develop SISO detector shows almost the same BER performance and convergence behavior as compared to the IDD receiver with the conventional optimal MAP SISO detector. However, in practical applications the complexity of our developed SISO detector can be ten times less than that of the most widely used minimum mean square error-soft interference cancellation (MMSE-SIC) SISO detector.

Accurate performance evaluation of direct-sequence pseudonoise code acquisition on Rayleigh fading channels is investigated. For fading channels the homogeneous Markov chain model, used to characterize the acquisition process over additive white Gaussian noise channels, is no longer valid due to the correlations between cell detections incurred by fading. Hence, the traditional direct and flow-graph approaches for performance evaluation of the code acquisition are not applicable to fading channels. In this paper, a new analysis is proposed for accurate evaluation of the acquisition performance on Rayleigh fading channels. The analysis is quite general and can include various search strategies, types of correlators, and test methods with different performance measures: probability mass function and/or moments of acquisition time. Analytical and simulation results show that the new method predicts the acquisition performance very accurately.

Pseudonoise code acquisition is investigated for constant hopping rate fast frequency-hopped (FFH)/M-ary frequency-shift keying systems under the effects of white Gaussian noise and band multitone jamming. In particular, serial search acquisition systems based on the traditional multiple-dwell test (up to three dwells) and three novel sequential tests are analyzed and compared. Analytical results show the following in a heavily jammed environment: (1) the inherent time diversity in an FFH system can significantly improve the acquisition performance of the multiple-dwell test and (2) the novel sequential tests can significantly outperform the multiple-dwell test. Our analytical results are verified by computer simulations.

Variable dwell-time code acquisition based on multiple-dwell or sequential linear tests is investigated for direct-sequence spread-spectrum systems on time-variant Rayleigh fading channels. Unlike in the conventional additive white Gaussian noise channels, the channel memory incurred by fading renders the exact analysis of the acquisition systems extremely difficult, if not impossible. In this paper, a novel method is developed to evaluate the mean acquisition time of the acquisition systems very accurately. The effects of Rayleigh fading are evaluated, and comparisons are made between double-dwell and sequential linear tests. Numerical results show that Rayleigh fading may result in 1-4-dB loss in performance, and the sequential linear test can outperform double-dwell test by a margin of 1-2 dB. The analytical results are verified by computer simulations.

Variable dwell-time code acquisition based on multiple-dwell and novel sequential tests is investigated for fast frequency hopped MFSK systems under the effects of white Gaussian noise and band multitone jamming. 1- and 2-dwell tests are of particularly interest for the multiple-dwell tests for practical consideration. Numerical results show that (i) diversity with fast frequency hopping can significantly improve the acquisition performance for 1- and 2-dwell tests, especially in a heavily jammed environment, and (ii) the proposed novel sequential tests significantly outperform 1- and 2-dwell tests and are quite robust to the effects of non-ideal jammer state information. Our analytical results are verified by computer simulations.

Variable-dwell time code acquisition based on multiple-dwell or sequential linear test is investigated for direct-sequence spread spectrum systems on time-varying multipath Rayleigh fading channels. Not like the case of conventional additive white Gaussian noise channels, the channel memory incurred by multipath fading renders the exact analysis of the acquisition systems extremely difficult, if not impossible. A novel method is developed to evaluate the mean acquisition time of the acquisition systems to any desired accuracy. The effects of multipath fading are evaluated, and comparisons are made between the multiple-dwell and sequential linear tests. Numerical results show that multipath fading may result in 1-4 dB loss in performance, and the sequential linear test can outperform the multiple-dwell test by a margin of 1-2.5 dB. The analytical results are verified by computer simulations.

A new method is proposed to analyze the performance of a biased square-law sequential detector when a signal is present. Starting from Albert's (1954) integral equations, the method evaluates the detection probability and the moments of the sample number very efficiently and accurately, using polynomial interpolations. Numerical examples show that the new method is much more efficient and/or accurate than the known methods. In addition, the analytical results are substantiated by computer simulations and Kendall's (1965) exact results for the cases of with and without signal present, respectively.