A new approach for performance analysis of orthogonal space–time block coding systems with antenna selection is presented. Antenna selection has been performed at the transmitter and/or at the receiver sides. Closed‐form expressions are derived for the approximate average bit error rate (BER) of the considered system for M ‐ary quadrature amplitude modulation and phase‐shift keying schemes. Different from other approaches presented in the literature, analytical expressions are derived for the average signal‐to‐noise ratio (SNR) gain obtained from each antenna selection scheme, and then using those SNR gains closed‐form expressions are obtained for the approximate average BER performance. The system performances of several forms of the presented scheme are evaluated and compared. It is shown that the results obtained from the mathematical expressions match closely with simulation results.

In this paper, we consider a dense ad hoc network with multicast type of traffic handling using a hierarchical routing with clustering. We investigate the scaling of throughput capacity versus the number of nodes and destinations. We construct an elementary spatial-temporal routing scheme that achieves the throughput capacity of a dense ad hoc wireless network with high probability as the number of nodes increases. The derived lower bound on the throughput capacity under the proposed routing strategy holds with probability one as the number of nodes goes to infinity. Finally, we provide numerical validation of the achievable throughput using a multicast capacity simulator based on the proposed constructive scheme.

This paper considers a general approach for the computation of all functional characteristics of a probabilistic wireless channel model using a bidirectional parametric description. It is shown that under mild conditions the WSSUS property is valid for these models and explicit relations are derived for the computation of the time-frequency autocorrelation from which one can easily derive the Doppler and delay power spectra. As an illustrative example, we consider the single ring of scatterers channel model. We also briefly mention how all these concepts can be generalized to the MIMO case.

The focus of this paper is on presenting new results on throughput capacity of wireless ad hoc networks with multicast traffic. In seminal works, Gupta and Kumar introduced a new line of research. It is about the asymptotic throughput capacity of dense wireless ad hoc networks as a function of the number of nodes in the network. In this paper, we present an upper bound on the throughput capacity of an ad hoc network with multicast traffic using a hierarchical routing strategy. We start first by generating the upper bound and the strategy gain for the 2-level hierarchical strategy. Then, we generalize the result for multi-level hierarchical routing by giving the recurrence expression of the multicast gain. Finally, we apply the basic result to a broadcast traffic in the network

Many models based on hidden Markov models were developed to model error bursts in communication channels. In this paper, we evaluate the effect of interleaving for the widely used Gilbert-Elliot model. An expression of the transition probability matrix is then derived. This allows, when having an identified error model, to simulate in an easy way the effects of any interleaving depth. Therefore, the choice of an interleaving degree and a forward error correction code (FEC) can be done easily.

The development of a 2400-b/s speech digitizer which provides an acceptable level of intelligibility and quality over land mobile satellite channels is described. Performance tests over simulated channels in the UHF band (800 MHz) are presented. The voice digitizer is a linear prediction (LPC) vocoder which uses a channel error correction and concealment procedure tailored to error statistics for a minimum-shift keyed (MSK) downlink to a moving vehicle. The error-handling technique is based on perceptual criteria and utilizes the parametric nature of LPC representation of speech. A single-error-correcting, single-burst-detecting (28, 20) fire code is shown to be the best choice for the application. The intelligibility of the vocoder is measured and compared to the standard LPC-10 algorithm. The major remaining sources of speech quality degradation due to channel errors are determined and ranked.>

Based on a finite Fourier transform of codewords over the finite field GF(q^{m}), some basic properties of the class of Goppa codes are presented. A new lower bound on the minimum distance for these codes is derived and applied to a subclass of Goppa codes which is. in fact. equivalent to a subset of punctured reversible cyclic codes. Furthermore. it is shown how the class of Goppa codes can be easily decoded in the context of this transformation by using the Berlekamp-Massey decoding algorithm. Through a slight extension of the procedure, it is also shown how this algorithm may be used m decode alternant codes up to their guaranteed error-correction capability.

the probability of an undetected error for these codes is presented. This method is then used to evaluate the error-detection performance of the shortened codes obtained from the two distance-4 Hamming codes adopted by CCITT X.25 for error control for packet-switched networks. We show that shortening a code does affect its error-detection performance.

This paper reports the results of a computer analysis of the distance properties of some of the best known rate 1/2, 1/3, and 1/4 codes to constraint length 14. The data include the truncated weight distributions of the codewords belonging to the incorrect subset which specifies the performance of the Viterbi algorithm as well as the minimum asymptotic growth rate of the weights of unmerged codewords which has been conjectured to be related to the length of error events produced by Viterbi decoders.

The distance properties of a class of rates2/3and3/4binary convolutional codes recently constructed by Paaske are reported. The data comprise the truncated input and output weight distributions of the codewords in the incorrect subset and the column distance function. which is strongly related to the computational effort of sequential decoding. The minimum asymptotic growth rate of the weights in the subset of unmerged codewords has been conjectured to be an important parameter; values of this parameter have also been included.

A[55, 16, 19]binary Goppa code and some related codes are described. These codes are found to contain more codewords than any previously known codes of the same length and minimum distance.

This paper presents an F8 microprocessor-based breadboard for the simulation of communication links using rate ½ binary convolutional codes in connection with Viterbi decoding, and which can be of value in the collection and analysis of statistical data relevant to such systems. The main purpose in the implementation of such a scheme has been to alleviate the high cost of running such simulations on macro or mini digital computers. Another advantage resides in the fact that the low cost of implementation of the final system makes it attractive as a teaching and training tool for young engineers in this important new field of communication theory. Moreover, with slight modifications, the system can be extended in a straightforward manner to handle a more general class of convolutional codes than the rate ½ codes, as well as transmission channels with more complex error statistics than the simple and rather academic binary symmetrical channel.