Broadband MIMO-OFDM wireless communications

Abstract

Abstract-Orthogonal frequency division multiplexing (OFDM) is a popular method for high data rate wireless transmission. OFDM may be combined with antenna arrays at the transmitter and receiver to increase the diversity gain and/or to enhance the system capacity on time-variant and frequency-selective channels, resulting in a multiple-input multiple-output (MIMO) configuration. This paper explores various physical layer research challenges in MIMO-OFDM system design, including physical channel measurements and modelling, analog beam forming techniques using adaptive antenna arrays, space-time techniques for MIMO-OFDM, error control coding techniques, OFDM preamble and packet design, and signal processing algorithms used for performing time and frequency synchronization, channel estimation, and channel tracking in MIMO-OFDM systems. Finally, the paper considers a software radio implementation of MIMO-OFDM.

MIPS cost estimation for OFDM-VBLAST systems

“…The implementation of a MIMO-OFDM system with N t transmit antennas and N r receive antennas can be carried out as shown in Figure 1. [4]. In this paper, we only consider symbol operations, hence the system starts after the mapper in the transmitter and ends with the de-mapper in the receiver.…”

“…Antenna 1 The data frame structure for each antenna is illustrated in figure 2, where the preamble portion has N t training symbols of length N I , and the user data portion has N data symbols of length N k , [4]. All the symbols have a Cyclic Prefix (CP) of length G to avoid inter-symbol interference.…”

Near-optimal pilot allocation in sparse channel estimation for massive MIMO OFDM systems

“…The combination of massive (or large-scale) multiple-input multiple-output (MIMO) and orthogonal frequency division multiplexing (OFDM) is expected to be the key technology for future communications [1]. However, this technique suffers from high complexity load in channel estimation due to the high dimensional channel matrix to be estimated.…”

Fairness Aware Downlink Scheduling Algorithm For Lte Networks

“…Indeed, advantages of LTE design arehigher user bit rates, lower delays, increased spectrum efficiency, reduced cost, and operational simplicity. To gain these goals LTE uses several technologies, which include Orthogonal Frequency Division Multiple Access (OFDMA) [3], Single Carrier Frequency Division Multiple Access (SC-FDMA) [4] and Multiple Input Multiple Output (MIMO) [5]. LTE uses OFDMA for downlink and SC-FDMA for uplink transmission [6].…”