Packet-Combining Demodulation Scheme for Cooperative MIMO-OFDM Transmission

This paper describes a demodulation scheme employing packet combining for packet-based cooperative multi-input multiple-output with orthogonal frequency division multiplexing (MIMO-OFDM). hi this paper, we consider the simplified cooperative MIMO-OFDM transmission model based on a two-hop relay network. The proposed demodulation scheme combines the packet signals of different transmit periods. After combining, we employ maximum likelihood detection (MLD) to separate the multiplexed sub-streams. We consider the L = 2 case: i.e. the first transmit period and the second transmit period are used. Because the source-terminal and relay-terminal are located in different positions, the proposed scheme utilizes the difference between the MIMO channel matrix of the first transmit period and that of the second transmit period. As a basic performance comparison, and assuming ideal link performance between source-terminal and relay-terminal and error-free relay processing, we describe a packet error rate (PER) performance comparison. The results confirm that the proposed packet-combining scheme yields relay transmission with an approximately 1.1 dB improvement in E_b/N₀ over direct transmission without the packet combining scheme.