Abstract :
MIMO Technology is an essential component of HSPA, LTE, LTE-A and its a key technology for LTE where adaptive switching modes at e-NB provides higher throughput for user close to e-NB and broadens its coverage range for user at edges of cell. MIMO combined with OFDMA is a crucial change in air interface of 4G as compared with 3G. To improve the performance of LTE downlink system, this paper investigate the MIMO modes adaptation schemes based on channel correlation, Rank, Doppler shift and SNR etc. 3GPP LTE has defined seven MIMO mode for adaptation and different Modulation and Coding Switching Scheme (MCS) to enhance the performance of LTE downlink. This paper is considering only four modes i.e., Spatial multiplexing for open loop and closed loop, transmit beam forming, and transmit diversity. This paper primarily focuses on how to take spatial correlation into account which also consider the highly Doppler channel for selecting particular MIMO mode. Simulation results show that correlation factor plays a critical factor for choosing index for switching of modes.
Keywords :
4G mobile communication; Doppler shift; Long Term Evolution; MIMO communication; OFDM modulation; array signal processing; correlation methods; diversity reception; encoding; frequency division multiple access; space division multiplexing; telecommunication switching; 3GPP LTE; 4G; Doppler channel; Doppler shift; HSPA; LTE downlink system; LTE-A; MCS; MIMO technology; OFDMA; SNR; adaptive switching modes; channel correlation; closed loop; correlation factor; coverage range; e-NB; mode switching; modulation-and-coding switching scheme; open loop; performance enhancement; spatial correlation based MIMO mode switching; spatial multiplexing; transmit beam forming; transmit diversity; Correlation; MIMO; Multiplexing; Signal to noise ratio; Switches; Transmitting antennas; Wireless communication; LTE; MIMO; OFDMA; beamforming; link adaptation; space-time coding; spatial multiplexing;
