We introduce a centralized joint network-channel coding scheme for maximized throughput and increased robustness against link failure in a communication network. We introduce RNC1(h,k) to multicast k independent data ...
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ISBN:
(纸本)9781424411993
We introduce a centralized joint network-channel coding scheme for maximized throughput and increased robustness against link failure in a communication network. We introduce RNC1(h,k) to multicast k independent data in a directed and acyclic network with capacity h, k <= h. The redundancy through path diversity increases the resistance of the network against link failure. An improved version of RNC1, RNC2(h,k), is introduced to guarantee the rate k for h-k flow failures. The proposed schemes exploit the network structure for code design, which results in a manageable design complexity.
AbstractThe goal of this thesis is to provide a unified concept of lossy-forwarding from the theoretical analysis to practical scheme design for the decode-and-forward-based multiple access relay channel (MARC) system...
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AbstractThe goal of this thesis is to provide a unified concept of lossy-forwarding from the theoretical analysis to practical scheme design for the decode-and-forward-based multiple access relay channel (MARC) system. To improve the performance of MARC with the relay subject to resources or/and time constraints, the erroneous estimates output from simple detection schemes are used at the relay are forwarded and exploited. A correlation is then found between two sequences: one is the network-coded sequence sent from the relay, and the other is their corresponding exclusive-OR-ed information sequence. Several joint network-channel coding (JNCC) techniques are provided in which the correlation is utilized to update the log-likelihood ratio sequences during the iterative decoding process at the destination. As a result, the bit error rate (BER) and frame error rate (FER) are improved compared with those of MARC with select DF strategy (SDF-MARC). The MARC proposed above is referred to as erroneous estimates-exploiting MARC (e-MARC).To investigate the achieved FER performance of the e-MARC system, the outage probability for e-MARC with two source nodes is theoretically derived. We re-formulate the e-MARC system and identify its admissible rate region according to the Slepian-Wolf theorem with a helper. Then, the outage probability is obtained by a set of integral over the rate region with respect to the probability density functions of all the links'' instantaneous signal-to-noise power ratios. It is found through simulations that, as one of the source nodes is far away from both the relay and destination, e-MARC is superior to SDF-MARC in terms of outage performance. Furthermore, a joint adaptive network-channelcoding (JANCC) technique is then proposed to support e-MARC with more source nodes. A vector is constructed at the destination in JANCC to identify the indices of the incorrectly decoded source node(s), and re-transmitted to the relay for requesting additional
The fabrication of lightweight, ultra-thin, low power and intelligent body-borne sensors leads to novel advances in wireless body area networks (WBANs). Depending on the placement of the nodes, it is characterized as ...
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The fabrication of lightweight, ultra-thin, low power and intelligent body-borne sensors leads to novel advances in wireless body area networks (WBANs). Depending on the placement of the nodes, it is characterized as in/on body WBAN;thus, the channel is largely affected by body posture, clothing, muscle movement, body temperature and climatic conditions. The energy resources are limited and it is not feasible to replace the sensor's battery frequently. In order to keep the sensor in working condition, the channel resources should be reserved. The lifetime of the sensor is very crucial and it highly depends on transmission among sensor nodes and energy consumption. The reliability and energy efficiency in WBAN applications play a vital role. In this paper, the analytical expressions for energy efficiency (EE) and packet error rate (PER) are formulated for two-way relay cooperative communication. The results depict better reliability and efficiency compared to direct and one-way relay communication. The effective performance range of direct vs. cooperative communication is separated by a threshold distance. Based on EE calculations, an optimal packet size is observed that provides maximum efficiency over a certain link length. A smart and energy efficient system is articulated that utilizes all three communication modes, namely direct, one-way relay and two-way relay, as the direct link performs better for a certain range, but the cooperative communication gives better results for increased distance in terms of EE. The efficacy of the proposed hybrid scheme is also demonstrated over a practical quasi-static channel. Furthermore, link length extension and diversity is achieved by jointnetwork-channel (JNC) coding the cooperative link.
In this paper, we develop a joint design method of network-channel Low Density Parity Check codes (LDPC) codes by constructing jointnetwork-channel parity check matrix. Random networkcoding is performed to provide s...
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In this paper, we develop a joint design method of network-channel Low Density Parity Check codes (LDPC) codes by constructing jointnetwork-channel parity check matrix. Random networkcoding is performed to provide side information for both the Source and Relay s transmission. This system matrix makes an easy way to collect all independent signal copies to provide a spatial diversity gain. And the complexity of networkcoding is linear to the block length ~O(n) Then, the optimization of jointnetwork-channel LDPC code is conducted in term of maximizing the system rate. Based on the jointnetworkchannel LDPC codes, we presents a protocol for wireless cooperative communications, which is very effective to combat the channel fading without much rise in system bandwidth and transmitting power. A traditional three-node model is built to describe the protocol where relay not only helps source to transmit but also has its own information to transmit.
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