Contemporary wireless systems combine aspects of network theory such as scheduling, throughput, and delay as well as information theory aspects such as capacity, coding, and power control. Design of such systems requires joint optimization of both network and physical layers. In this paper, we analyze a single-user communication system composed of a transmitter preceded by a queue used for retransmissions, Gaussian block-fading channel, and a receiver. The system average delay is optimized by using combined power/rate control under average power constraints. Dynamic programming is used for calculating the optimized policies using numerical analysis as well as analytic analysis for asymptotically large buffer size. Asymptotic results are obtained for all combinations of fixed or variable power and rate controls. The most important result extends the "water-filling" result for systems with average delay constraint

A new algorithm is proposed for the multiple access channel with flat Rayleigh fading in a single cell. It is assumed the fading values are known to both the receiver and transmitter. Unlike previous algorithms, this algorithm considers the throughput under constraints of outage and delay. This is done by combining the advantages of TDMA (low delay, small outage) with the advantages of the optimized throughput algorithm. In the proposed algorithm only one user transmits at any moment making successive decoding and/or rate splitting unnecessary. A single parameter controls the similarity of the algorithm to TDMA vs. the similarity to the optimized throughput algorithm. The algorithm's performance is a continuous function of the parameter i.e., if the algorithm is more TDMA like, its performance (throughput, delay, outage) are also similar to TDMA and vice versa.

We present here a novel coding approach in the wavelet transform domain, based on a pruned tree structure of the transformed signal. The approach is based on the observation that on one hand a large portion of the wavelet transform samples may be nullified without significant loss of reconstruction quality, and on the other hand samples with relatively high energy tend to concentrate around local transients of the source signal. A pruned tree is built in which each node consists of a cluster of samples of the same scale which are centered at a local transient. The branches of the tree connect nodes of adjacent scales. The tree structure is coded by a simple binary code. A vector quantizer is used to code each node. Compression ratios of 1:25 on a gray-level images are achieved with good quality.