ملخص البحث :

Within the current research, a puncturing procedure, which is novel as well as effective for attaining rate compatibility is presented. The low-density parity check codes (LDPC) of parallel concatenation gallager codes (PCGC) has been applied which includes the Quasi-Cyclic (QC) LDPC codes as one component, and two irregular components of the (LDPC) within the forward error correction coding (FEC). The puncturing procedure is effective as well as unique within this research. The LDPC component codes help create the variable code rates and the decoding challenges are reduced. Parallel concatenation has been used to apply the (QC-PCGC). They are component codes applied with the puncturing procedure to establish code rate and to decrease decoding challenges faced with several applications. The punctured coding system is tested using different channels. The simulation outcomes indicate that there is enhanced performance as compared to using the traditional PCGC or the LDPC long unique code which makes use of the same parameters, before and after puncturing. For the communication applications in the future, for instance, the 5G, the coding system structure that has been presented can be used. It is possible since there is a need for flexibility within forward error control coding and decoding and encoding should have lower complexity levels.

ملخص البحث :

In this work, we proposed Offset-Quadrature Amplitude Modulation (OQAM) for Discrete Wavelet Transform (DWT) as alternative of Multi-Carrier Modulation (MCM) systems. Instead of the upsampler in the conventional DWT-MCM, OQAM is used in each level. In OQAM, each symbol will be separate into two components, in-phase and quadrature. With OQAM, maximum phase variation will decrease to its half value, which means that the performance of the RF power amplifier will improved. In addition, half symbols period will offset (stagger) the quadrature and in-phase components of the modulated signal to achieve low bit error rate. By contrast, in conventional orthogonal frequency division multiplexing (OFDM), without using the guard interval (Cyclic Prefix (CP)), inherent interferences cause degeneration in received symbols. In this paper, the proposed system model enhanced the spectrum efficiency and becomes more robust to the frequency selective environments. The simulation results illustrate that our proposed system model improves the system performance in terms of probability of errors compared with the OFDM system..

ملخص البحث :

WiMAX system performance can be significantly improved to achieve excellent error correction performance by utilizing powerful Forward Error Correction Codes. We present a class of parallel concatenated codes called Multiple Parallel Concatenated Gallager Codes (MPCGC) based on using (LDPC) component codes that is used in IEEE 802.16/WiMAX. Computer simulation results confirm that the proposed MPCGCs-WiMAX system shows better performance with an improvement by 0.3 dB gain when compared to a single long LDPC-WiMAX system. Moreover, by using the proposed coding scheme, lower computational complexity can be achieved than the long LDPC code due to multiple smaller lower codes. The advantages of the MPCGCs structure have the potential to be extended to other applications where reduced complexity and flexibility in forward error control coding are required

ملخص البحث :

An efficient low complexity puncturing method has studied to achieve rate compatible. The parallel concatenation codes are use mixing of one component of Quasi-Cyclic (QC) low-density parity check codes LDPC codes with two component of (LDPC) in linear coding. The proposed QC-PCGC have lower computation complexity when compared with traditional punctured PCGC. The decreasing in the complexity analysis yields to the reducing in the memory requirement for the encoding/decoding system. It is possible to use the suggested coding system structure in the future communication applications like fifth generation (5G), where it is needed to have coding flexibility, with less complexity in encoding and decoding.

ملخص البحث :

ملخص البحث :