scholarly journals Adaptive Combined Channel Network Coding for Cooperative Relay Aided Cognitive Radio Networks

Information ◽  
2021 ◽  
Vol 12 (8) ◽  
pp. 320
Author(s):  
Mohamed S. AbuZeid ◽  
Yasmine A. Fahmy ◽  
Magdy S. El-Soudani
Keyword(s):  
Cognitive Radio ◽  
Network Coding ◽  
Channel Coding ◽  
System Throughput ◽  
Cooperative Relay ◽  
Secondary System ◽  
Channel Network ◽  
Time Saving ◽  
Channel Conditions ◽  
Combined Channel

Cognitive radio (CR) is one of the emerging technologies for 4G/5G applications. Cooperative relay communications and network coding are some techniques that helped in enhancing the CR applications. This paper considers a primary broadcasting system for multimedia video streaming applications that broadcasts data to the primary users and to an aiding cooperative relay CR secondary system. The cooperative overlay secondary system can use many error control coding techniques for point-to-point data retransmissions such as channel coding, network coding, and combined coding techniques to enhance the system performance under variable channel conditions. This work proposes a novel adaptive combined channel network coding (AC2NC) technique for data retransmissions. The new AC2NC first analyses the channel feedback information and then selects the best retransmission coding technique based on the targeted bandwidth or transmission time optimization. This is instead of using a single static channel or network coding technique with dynamic channel conditions. The proposed AC2NC improves the system throughput, decreases the retransmission time, and avails more spectrum access opportunities for the secondary system’s own data transmissions. The AC2NC relative bandwidth and time saving opportunities for CR users can exceed 90% under certain channel conditions versus some static coding techniques.

scholarly journals Throughput Maximization Based on Optimal Access Probabilities in Cognitive Radio System

2021 ◽  
Author(s):  
Lian Zhao
Keyword(s):  
Cognitive Radio ◽  
Primary User ◽  
Throughput Maximization ◽  
System Throughput ◽  
Secondary System ◽  
Spectrum Utilization ◽  
Secondary Users ◽  
Radio System ◽  
Low Efficiency ◽  
Service State

Well-established fact shows that the fixed spectrum allocation policy conveys to the low spectrum utilization. The cognitive radio technique promises to improve the low efficiency. This paper proposes an optimized access strategy combining overlay scheme and underlay scheme for the cognitive radio. We model the service state of the system as a continuous-time Markov model. Based on the service state, the overlay manner or/and the underlay manner is/are used by the secondary users. When the primary user is not transmitting and only one secondary user has the requirement to transmit, the secondary system adopts the overlay scheme. When the primary user is transmitting and the secondary users want to transmit simultaneously, an underlay scheme with an access probability is adopted. We obtain the optimal access probability in a closed form which maximizes the overall system throughput

scholarly journals A Joint Channel-Network Coding Based on Product Codes for the Multiple-Access Relay Channel

2012 ◽  
Vol 2012 ◽  
pp. 1-13 ◽  
Author(s):  
Tafzeel ur Rehman Ahsin ◽  
Slimane Ben Slimane
Keyword(s):  
Network Coding ◽  
Channel Coding ◽  
Multiple Access ◽  
Relay Channel ◽  
Decoding Algorithm ◽  
Channel Network ◽  
Product Codes ◽  
Coding Scheme ◽  
Coding Schemes ◽  
Joint Channel

The multiple access relay channel with network coding has the potential to achieve diversity and improve coverage of wireless networks. Its network coding scheme provides an extra redundancy that can be used at the receiver to improve the performance of the cooperating users. This paper shows that the combination of channel coding and network coding, in the multiple access relay channel, can be seen as a product code with rows formed by the code-words of the individual channel codes of the users and columns formed by the network coding code-words. This new representation allows the use of any decoding algorithm of product codes at the receiver to decode the information data of the cooperating users. This decoding process is a complete joint channel-network decoding algorithm as it sees the combination of the two coding schemes as a single coding scheme. It also gives the possibility to use network coding schemes more powerful than conventional XOR-based network coding. The obtained results show that the proposed product-based network coding structure can improve the performance of the multiple-access relay channel without reducing its efficiency and allow a very flexible cooperation between the involved users.

scholarly journals Throughput Maximization Based on Optimal Access Probabilities in Cognitive Radio System

2021 ◽  
Author(s):  
Lian Zhao
Keyword(s):  
Cognitive Radio ◽  
Primary User ◽  
Throughput Maximization ◽  
System Throughput ◽  
Secondary System ◽  
Spectrum Utilization ◽  
Secondary Users ◽  
Radio System ◽  
Low Efficiency ◽  
Service State

Well-established fact shows that the fixed spectrum allocation policy conveys to the low spectrum utilization. The cognitive radio technique promises to improve the low efficiency. This paper proposes an optimized access strategy combining overlay scheme and underlay scheme for the cognitive radio. We model the service state of the system as a continuous-time Markov model. Based on the service state, the overlay manner or/and the underlay manner is/are used by the secondary users. When the primary user is not transmitting and only one secondary user has the requirement to transmit, the secondary system adopts the overlay scheme. When the primary user is transmitting and the secondary users want to transmit simultaneously, an underlay scheme with an access probability is adopted. We obtain the optimal access probability in a closed form which maximizes the overall system throughput

A survey on network coding: From traditional wireless networks to emerging cognitive radio networks

2014 ◽  
Vol 46 ◽  
pp. 166-181 ◽  
Author(s):  
Muhammad Zubair Farooqi ◽  
Salma Malik Tabassum ◽  
Mubashir Husain Rehmani ◽  
Yasir Saleem
Keyword(s):  
Wireless Networks ◽  
Cognitive Radio ◽  
Network Coding ◽  
Cognitive Radio Networks ◽  
Radio Networks

FULL-RATE AND LOW-COMPLEXITY SPACE-TIME BLOCK CODING CONCATENATED WITH CHANNEL CODES

2007 ◽  
Vol 06 (01) ◽  
pp. 5-14 ◽  
Author(s):  
XIANGBIN YU ◽  
GUANGGUO BI
Keyword(s):  
Channel Coding ◽  
Turbo Code ◽  
Multiple Antennas ◽  
Low Complexity ◽  
Space Time ◽  
System Throughput ◽  
Time Block ◽  
Coding Schemes ◽  
Full Diversity ◽  
Full Rate

Space-time block (STB) coding has been an effective transmit diversity technique for combating fading recently. In this paper, a full-rate and low-complexity STB coding scheme with complex orthogonal design for multiple antennas is proposed, and turbo code is employed as channel coding to improve the proposed code scheme performance further. Compared with full-diversity multiple antennas STB coding schemes, the proposed scheme can implement full data rate, partial diversity and a smaller complexity, and has more spatial redundancy information. Moreover, using the proposed scheme can form efficient spatial interleaving, thus performance loss due to partial diversity is effectively compensated by the concatenation of turbo coding. Simulation results show that on the condition of the same system throughput and concatenation of turbo code, the proposed scheme has lower bit error rate (BER) than those low-rate and full-diversity multiple antennas STB coding schemes.

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