of the Dissertation Reliability-output Decoding and Low-latency Variable-length Coding Schemes for Communication with Feedback

We consider binary abelian codes of length pq where p and q are prime rational integers under some restrictive hypotheses. In this case, we determine the idempotents generating minimal codes and either the respective weights or bounds of these weights. We give examples showing that these bounds are attained in some cases.

In this paper, a transmit diversity technique using chip level space time block coding (chip-STBC) is investigated for the downlink transmission of multicarrier direct sequence code division multiple access (MC-DS-CDMA) based cognitive radio base station. Synchronous transmission of multiple users’ signals over fast fading frequency selective Rayleigh channel is considered. Conventional symbol ...

This paper presents an optimization problem of spreading codes (sequences) in asynchronous Direct Sequence Code Division Multiple Access (DS/CDMA) systems. Bit Error Rate (BER) is one of the performance measurements and it is related to the spreading sequences mathematically. Therefore, the performance of CDMA systems highly depends on the assignment of the unique spreading sequences to the use...

In this paper, a new channelization code tree structure, namely an ROVSF (rotated-orthogonal variable spreading factor) code tree, is defined and investigated. Most existing code assignment schemes are investigated on the OVSF (orthogonal variable spreading factor) code tree in WCDMA systems. The main work of this investigation is to exploit and justify the new properties of the ROVSF code tree...

Optimum near-far resistance is studied for synchronous dual-rate DS/CDMA systems. Three multi-rate access schemes are considered: multi-code (MC) access where high-rate users multiplex their data bits onto multiple codes and form a single-rate system ; variable spreading length (VSL) access where the spreading lengths of signature sequences are inversely proportional to users' data rates; and v...

in this study, stability of geosynthetic reinforced soil retaining walls investigated using plaxis code that is based on finite element method. the effects of axial stiffness, length and vertical space between geosynthetic layers, internal friction angle of soil wall and cohesion of foundation on deformations of wall and maximum axial force of geosynthetic have been investigated. results of ana...

Code Division Multiple Access (CDMA) is one of the important radio access technologies for applications in wireless mobile communication systems. A CDMA system requires a large number of suitable spreading sequences having minimum cross-correlation. Many spreading codes have been studied, their cross-correlation values have been found and reported in this paper. Their suitability for applicatio...