Performance evaluation and energy efficiency of random network coding in LTE-Advanced

In this paper, we propose integration of random network coding (R-NC) sublayer at the Radio Link Control/Multiple Access Control (RLC/MAC) layer boundary within the 3GPP Long Term Evolution (LTE) Radio Access Network (RAN) protocol stack. R-NC is introduced as a simple alternative to the MAC/Physical Layer (PHY) Hybrid Automatic Repeat reQuest (HARQ) protocol for reliable RLC protocol data unit (PDU) transmission over the radio interface between the base station (eNB) and the mobile user equipment (UE). To evaluate and compare the performance of the R-NC-based solution against the standardized HARQ-based one, we develop a novel link-level simulator which combines packet-level Finite-State Markov Chain (FSMC) channel models and existing LTE PHY layer simulators. Using this simulator, the R-NC and the HARQ-based alternatives are compared with respect to continuous transmission of RLC PDUs between the eNB and the UE over a direct radio link or via relay-node (RN) assisted multi-hop connection. The focus of this technical study is on the possible throughput, energy, delay and implementation complexity reduction benefits of the proposed R-NC-based solution over the HARQ-based protocol.