Design of Simulation System for LTE-U Using 5 GHz Band in MATLAB

摘要

Unused spectrum is being a limited commodity for the telecom industry. However, up to 500 MHz of unlicensed spectrum in 5 GHz band is in use for several applications and services, particularly in WiFi around the world. Unlicensed spectrum has foreseen to play a vital role in 5G. It is already under discussion at different forums that how the unlicensed band advantage can promote 4G Long Term Evolution (LTE) networks. Long Term Evolution Unlicensed (LTE-U) is an extension of existing LTE mobile networks, and allow LTE technology to use unlicensed bands as an adjunct to the licensed band. It will not only deliver a better user experience to end users but also boost capacity for network operators. In this paper, a Simulink based LTE PDSCH (Physical Downlink Shared Channel) model is introduced which uses the 5 GHz band according to the specifications prescribed by LTE-U Forum and 3GPP (Third Generation Partnership Project). It demonstrates multi-codeword transmission within a small cell from an eNodeB to a User Equipment (UE). LTE enabling technologies like OFDMA, closed-loop spatial multiplexing, turbo channel coding and link adaptations are used to design this model. Minimum mean square error (MMSE) technique as a linear detection method is used for spatially multiplexed Multiple Input Multiple Output (MIMO). Bit error rate is analyzed for QPSK, 16-QAM, and 64-QAM and compared for hard and soft decisions MMSE based MIMO detection. Fairly improved throughputs are obtained for multi-antenna configurations considering the low mobility scenarios and low correlation settings between links.