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Coded Cooperation for Multiway Relaying in Wireless Sensor Networks.

Si Z, Ma J, Thobaben R - Sensors (Basel) (2015)

Bottom Line: In particular, for the message broadcasting from the relay, we construct multi-edge-type (MET) SC-LDPC codes by repeatedly applying coset encoding.Due to the capacity-achieving property of the SC-LDPC codes, we prove that the capacity region can theoretically be achieved by the proposed MET SC-LDPC codes.Numerical results with finite node degrees are provided, which show that the achievable rates approach the boundary of the capacity region in both binary erasure channels and additive white Gaussian channels.

View Article: PubMed Central - PubMed

Affiliation: Key Lab of Universal Wireless Communications, Ministry of Education, Beijing University of Posts and Telecommunications (BUPT), 100876 Beijing, China. sizhongwei@bupt.edu.cn.

ABSTRACT
Wireless sensor networks have been considered as an enabling technology for constructing smart cities. One important feature of wireless sensor networks is that the sensor nodes collaborate in some manner for communications. In this manuscript, we focus on the model of multiway relaying with full data exchange where each user wants to transmit and receive data to and from all other users in the network. We derive the capacity region for this specific model and propose a coding strategy through coset encoding. To obtain good performance with practical codes, we choose spatially-coupled LDPC (SC-LDPC) codes for the coded cooperation. In particular, for the message broadcasting from the relay, we construct multi-edge-type (MET) SC-LDPC codes by repeatedly applying coset encoding. Due to the capacity-achieving property of the SC-LDPC codes, we prove that the capacity region can theoretically be achieved by the proposed MET SC-LDPC codes. Numerical results with finite node degrees are provided, which show that the achievable rates approach the boundary of the capacity region in both binary erasure channels and additive white Gaussian channels.

No MeSH data available.


One example of the multiway relay channel with full data exchange. (a) The users transmits to the relay in turn, and the messages may be overheard by other users; (b) The relay broadcasts to all the users.
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f2-sensors-15-15265: One example of the multiway relay channel with full data exchange. (a) The users transmits to the relay in turn, and the messages may be overheard by other users; (b) The relay broadcasts to all the users.

Mentions: In Figure 2, we give a simple example of the above multiway relay channel. The example system consists of four users, and one of them is selected as the relay. In the first round of transmission, the message m1 from U1 is successfully received by both the relay and the user U2. The message m2 from U2 is successfully received by the relay and the user U3. The message m3 is only correctly received at the relay Each user can use the messages he has overheard together with his own message as the side information for decoding. That is, U1 has only his own message m1 as the side information. U2 has m1 and m2 as the a priori information, and U3 has m2 and m3 as the a priori information for the decoding. In the end of the first phase, each user informs the relay about what side information he has. This can be realized at each user by sending the indexes of his received messages to the relay. The number of bits needed to represent the index of one message is ⌈log2(K − 1)⌉, where K is the number of users. The total number of bits for each user to send the knowledge of available information is at most (K ‒ 2) ⌈log2(K − 1)⌉. For the example in Figure 2, each user only needs four bits. Comparing to the length of the messages, the resulting overhead and latency are negligible. In the broadcast phase, the relay delivers the missing messages to each user, i.e., {m0,m2,m3} to U1, {m0,m3} to U2 and {m0,m1} to U3. The challenge for the relay is then how to realize the information broadcasting efficiently and reliably.


Coded Cooperation for Multiway Relaying in Wireless Sensor Networks.

Si Z, Ma J, Thobaben R - Sensors (Basel) (2015)

One example of the multiway relay channel with full data exchange. (a) The users transmits to the relay in turn, and the messages may be overheard by other users; (b) The relay broadcasts to all the users.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4541830&req=5

f2-sensors-15-15265: One example of the multiway relay channel with full data exchange. (a) The users transmits to the relay in turn, and the messages may be overheard by other users; (b) The relay broadcasts to all the users.
Mentions: In Figure 2, we give a simple example of the above multiway relay channel. The example system consists of four users, and one of them is selected as the relay. In the first round of transmission, the message m1 from U1 is successfully received by both the relay and the user U2. The message m2 from U2 is successfully received by the relay and the user U3. The message m3 is only correctly received at the relay Each user can use the messages he has overheard together with his own message as the side information for decoding. That is, U1 has only his own message m1 as the side information. U2 has m1 and m2 as the a priori information, and U3 has m2 and m3 as the a priori information for the decoding. In the end of the first phase, each user informs the relay about what side information he has. This can be realized at each user by sending the indexes of his received messages to the relay. The number of bits needed to represent the index of one message is ⌈log2(K − 1)⌉, where K is the number of users. The total number of bits for each user to send the knowledge of available information is at most (K ‒ 2) ⌈log2(K − 1)⌉. For the example in Figure 2, each user only needs four bits. Comparing to the length of the messages, the resulting overhead and latency are negligible. In the broadcast phase, the relay delivers the missing messages to each user, i.e., {m0,m2,m3} to U1, {m0,m3} to U2 and {m0,m1} to U3. The challenge for the relay is then how to realize the information broadcasting efficiently and reliably.

Bottom Line: In particular, for the message broadcasting from the relay, we construct multi-edge-type (MET) SC-LDPC codes by repeatedly applying coset encoding.Due to the capacity-achieving property of the SC-LDPC codes, we prove that the capacity region can theoretically be achieved by the proposed MET SC-LDPC codes.Numerical results with finite node degrees are provided, which show that the achievable rates approach the boundary of the capacity region in both binary erasure channels and additive white Gaussian channels.

View Article: PubMed Central - PubMed

Affiliation: Key Lab of Universal Wireless Communications, Ministry of Education, Beijing University of Posts and Telecommunications (BUPT), 100876 Beijing, China. sizhongwei@bupt.edu.cn.

ABSTRACT
Wireless sensor networks have been considered as an enabling technology for constructing smart cities. One important feature of wireless sensor networks is that the sensor nodes collaborate in some manner for communications. In this manuscript, we focus on the model of multiway relaying with full data exchange where each user wants to transmit and receive data to and from all other users in the network. We derive the capacity region for this specific model and propose a coding strategy through coset encoding. To obtain good performance with practical codes, we choose spatially-coupled LDPC (SC-LDPC) codes for the coded cooperation. In particular, for the message broadcasting from the relay, we construct multi-edge-type (MET) SC-LDPC codes by repeatedly applying coset encoding. Due to the capacity-achieving property of the SC-LDPC codes, we prove that the capacity region can theoretically be achieved by the proposed MET SC-LDPC codes. Numerical results with finite node degrees are provided, which show that the achievable rates approach the boundary of the capacity region in both binary erasure channels and additive white Gaussian channels.

No MeSH data available.