Dynamic two-threshold flow control scheme for 3GPP LTE-A relay networks

Relaying technology is a cost-effective solution for achieving throughput enhancement for cell-edge users or extending the cell coverage for the 3GPP LTE-A systems. In this study, we investigate the flow control scheme in the LTE-A relay networks employing the Type-I relay nodes (RNs). However, the buffer-overflow problem [7, 8] caused by high-speed arrival traffic and the handover forwarding problem caused by UE´s handover are two main issues that affect the performance of 3GPP LTE-A relay networks. To mitigate these problems, we present a dynamic two-threshold flow control scheme (DTFCS) which can dynamically adjust the upper buffer-threshold of RN based on the channel quality. Results showed that DTFCS can reduce 40% of the total number of forwarding packets during the handover when compared with the two-threshold flow control scheme. Additionally, when the proposed scheme is compared to single-threshold flow control scheme, DTFCS excels by imposing much less signaling overhead on the expense of a slight increase in the number of forwarding packets.