In WCDMA, channelization is achieved by assigning OVSF codes to different users. The codes in a Node-B are valuable and limited. Much research has been devoted to devising OVSF code-assignment strategies to support as many users as possible. A number of the strategies suffer from a “code-set fragmentation” problem, which increases the call blocking probability (CBP) on the Node-B. In order to r...

Generating optimal code is a challenging problem. Traditional compilers break down the problem complexity by solving the main interdependent compilation tasks (that is, instruction selection, register allocation and instruction scheduling) in stages, and optimizing each stage individually using heuristics. While this approach achieves good results, it clearly compromises on the generated code q...

Transmit waveform design is one of the most important problems in active sensing and communication systems. This problem, due to the complexity and non-convexity, has been always the main topic of many papers for the decades. However, still an optimal solution which guarantees a global minimum for this multi-variable optimization problem is not found. In this paper, we propose an attracting met...

In this paper the performance of diierent coding schemes for direct-sequence spread-spectrum (DS-SS) with multiple-access (MA) interference in a nonselective Rayleigh fading channel is considered. A conventional 64-ary orthogonal code (M 64) transmitting 6 bits of information is examined rst. Each of the 64 code symbols in the M 64 code is assumed to be spread by a random sequence of length N, ...

We propose three new design algorithms for jointly optimizing source and channel codes. The joint designs combine channel-optimized vector quantization (COVQ) for the source code with rate-compatible punctured convolutional (RCPC) coding for the channel code. Our objective is to minimize the average end-to-end distortion. For a given channel SNR and transmission rate, our joint source and chann...

The goal of the flutter shutter is to make uniform motion blur invertible, by a “fluttering” shutter that opens and closes on a sequence of well chosen sub-intervals of the exposure time interval. In other words, the photon flux is modulated according to a well chosen sequence called flutter shutter code. This article provides a numerical method that computes optimal flutter shutter codes in te...

Source coding, also known as data compression, is an area of information theory that deals with the design and performance evaluation of optimal codes for data compression. In 1952 Hu man constructed his optimal code that minimizes the average code length among all pre x codes for known sources. Actually, Hu man codes minimizes the average redundancy de ned as the di erence between the code len...

Minimum storage regenerating (MSR) codes form a special class of maximum distance separable (MDS) codes by providing mechanisms for exact regeneration of a single code block in their codewords by downloading the minimum amount of information from the remaining code blocks. As a result, the MSR codes find application to distributed storage systems to enable node repairs with the optimal repair b...