محمد عبد الزهرة احمد الدليمي

The fifth generation of telecommunication systems is a familiar name in recent years. Many countries around the world have chosen this generation as the basic generation in telecommunications. In this paper, we will first have an overview of the history of the formation of different generations of systems. Then we will review the features, architecture and challenges and solutions to the challenges in fifth generation telecommunication systems. With all the powerful features that the fifth generation has, the future 5G networks must have important factors such as more bandwidth, use of smart antennas, small cells, virtualization reality, virtual software, etc. to be able to provide data rates for devices connected to the network and provide better services to their users. Studying fifth-generation telecommunications systems to address existing challenges is now the field of much research.

In this paper, the communication Wireless channel is simulated comprehensively with utilizing orthogonal frequency division multiplexing (OFDM) technique for two different modulation scheme which are Binary Phase shift keying (BPSK) and Quadrature amplitude modulation (16 QAM). Also the bit error rate (BER) performance of different types of wireless communication channels were observed and evaluated. The simulation is basically carried out by MATLAB where, a wireless communication system with transmitter, channel and receiver are built and coded by. At transmitter side, 16 QAM modulation and OFDM technique were used to modify the input digital signal. Thus, the demodulator of 16 QAM and equalizer of OFDM technique were applied at receiver to recover the signal. Three different types of channel which are Additive White Gaussian Noise (AWGN) channel, known multipath channel and unknown multipath channel were used whose BER performance was obtained and evaluated. The BER is key point to indicate the performance of system is good or not. Moreover, the theoretical results of the BER under different channel were calculated and compared with the simulation results to make sure the simulation is correct. Hence, wireless communication system could have the best performance under AWGN channel among three channels. Also based on this observation, it would always be best to try and have a known multipath channel as a significantly better error performance can be made and the data rate does not necessarily have to suffer. In all the study carried out, there was a significant accuracies of 100% are investigated as all results came out as intended and an accurate positive analysis was able to be made as a result.

Encryptions can play an essential role in securely communication transmissions. It can be used to raise the reliability of any communication system such as satellite communication and wireless Local Area Network (LAN). Security should satisfy and reassure the data transmission arrival to a specific destination. In this paper, a welldefined and powerful encryption technique is suggested, it can be exploited for securely communication transmissions. This technique utilizes An artificial neural network (ANN) of Multi-Layer Perception (MLP). It is used to efficiently encrypt text information into useful codes. Significant accuracies of 100% are investigated for data encryption and decryption.

The Irregular Repeat Accumulate Codes are extracted from repeat accumulate (RA) codes where the repetition stand for (R) is performed on the bits but not evenly for all bits. Furthermore, The IRA codes are considered as a form of LDPC code. This type of a LDPC code is used in the second generation of broadcasting of the digital video (DVB-S2) which is a new standard in Satellite communications that wide spreads in Europe, which looks promising to achieve a good spectral efficiency by granting the ability to use a very large length of codewords (frames) with different code rates as well as different modulation schemes. Another advantage in this scheme of coding is introducing a very high performance which is increased in each iteration up to reach the maximum iteration, since the message is corrupting through a noisy channel. Hence, the high reliability is required which is provided by IRA codes. In this dissertation, we will firstly make a general review of the IRA codes as encoder channel then according to the DVB-S2 specifications. Afterward, we are going to introduce new code rates which are almost between the standard ones which have a better performance. The generating and implementing of those codes will be explained and discussed in details as well as the decoding algorithm which is Sum-product algorithm (SPA).Moreover, we will have a look at some of the limitations and challenges for encoding and decoding of LDPC and IRA codes in the Literature survey which shows them by highlighting the recent work and what other people in this area have done in the last few years. Finally, our results which are extracting from the simulation by Matlab R2015a will be justified any improvement in the performance of our codes design. To sum up, we showed that the general performance of the IRA codes in the using normal frames is much better than in the case of short frame but that will be at the price of the cost and the implementation latency. Those new codes can be utilized as a tradeoff between the spectral efficiency and the power efficiency which might necessary for some type of application.