Mixed Noisy Network Coding and Cooperative Unicasting in Wireless Networks

• Published in: IEEE transactions on information theory Vol. 61; no. 1; pp. 189 - 222
• Main Authors: Behboodi, Arash, Piantanida, Pablo
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.01.2015; The Institute of Electrical and Electronics Engineers, Inc. (IEEE); Institute of Electrical and Electronics Engineers
• Subjects: Artificial neural networks; Codes; Coding theory; composite channel; compute-and-forward; constant gap; Cooperative unicasting; decode-and-forward; Decoding; Encoding; Information Theory; Mathematics; Network coding; Noise; Noise measurement; noisy network coding; Normal distribution; outage capacity; quantize-map-andforward; Relays; Unicast; wireless networking; quantize-map-and-forward; noisy network coding; decode-and-forward; outage capacity; Cooperative unicasting; wireless networking; composite channel; compute-and-forward; constant gap; quantize-map-and- forward
• ISSN: 0018-9448; 1557-9654
• DOI: 10.1109/TIT.2014.2368564

The problem of communicating a single message to a destination in presence of multiple relay nodes, referred to as cooperative unicast network, is considered. First, we introduce mixed noisy network coding (MNNC) scheme which generalizes noisy network coding where relays are allowed to decode-and-forward (DF) messages while all of them (without exception) transmit noisy descriptions of their observations. These descriptions are exploited at the destination and DF relays aim to decode the transmitted messages while creating full cooperation among the nodes. Moreover, the destination and DF relays can independently select the set of descriptions to be decoded or treated as interference. This concept is further extended to multihopping scenarios, referred to as layered MNNC, where DF relays are organized into disjoint groups representing one hop in the network. For cooperative unicast additive white Gaussian noise (AWGN) networks, we show that-provided DF relays are properly chosen-MNNC improves over all previously established constant gaps to the cut-set bound. Second, we consider the composite cooperative unicast network where the channel parameters are randomly drawn before communication starts and remain fixed during the transmission. Each draw is assumed to be unknown at the source and fully known at the destination but only partly known at the relays. We introduce through MNNC scheme the concept of selective coding strategy (SCS) that enables relays to decide dynamically whether, in addition to communicate noisy descriptions, is possible to decode and forward messages. It is demonstrated through slow-fading AWGN relay networks that SCS clearly outperforms conventional coding schemes.