Project 2: Capacity of MIMO Channels with Known Channel State Information at Transmitter (CSIT)
Abstract – The multiple-input and multiple-output (MIMO) systems are regarded as one of the most significant research areas in wireless communication. Such systems have the capacity of providing higher data throughput and bandwidth efficiency without additional bandwidth and power requirement compared with conventional single-input and single-output (SISO) systems. This paper reviews the basic background information of MIMO system, and then discusses the capacity of MIMO channels with known channel station information at transmitter (CSIT) under various channel parameters such as channel transfer ...view middle of the document...
On the other hand, within an MIMO system the data stream with high rate is split into multiple sub-streams, each with a lower rate. All the sub-streams will be transmitted through different antennas at the same frequency channel, which is also known as multi-path in which the signals will propagate through different routes in the air. When these signals with different time delay (also known as multi-path spread delay) arrive at the receive antenna array, the receiver can divide these streams and create parallel channels for free, resulting in the elimination of the inter-symbol interference (ISI) and remarkable improvement of system capacity. That is a key feature of MIMO system that turning multi-path propagation, which is usually regarded a drawback in wireless communication, into a benefit for the user. In addition, it is generally known that channel state information (CSI) is strongly related
Xiao Ling (z3265329)
Weichen Sun (z3281272)
to the capacity of the MIMO channel. In order to achieve higher channel capacity, the transmitter should know the instantaneous CSI completely, or even partial CSI could be utilized to improve the channel capacity. However, the CSIT would too large to process in practical, which might be a heavy load for the transmitter. Thus, a tradeoff between the improvement of channel capacity and the degree of completeness of the CSI available at the transmitters has to be made. Furthermore, the average CSI is provided instead of the instantaneous CSI in fast time-fading channels . With CSIT, the waterfilling rule then could be utilized to optimize the MIMO channel capacity. According to the waterfilling rule, the sum of transmit power level and the noise power level of each sub-channel in MIMO system should be a constant value. That means the transmitters send data on each sub-channel with different power level, more power are user for those sub-channels with less noise power and vice versa. As a result, the overall channel capacity could be obtained without the requirements of more transmit power. In this paper, the paper discussed the performance of a static 2x2 MIMO system in channels with different transfer matrix and signal-to-noise-ratio. The rest of this paper is organized as follows: the next section will cover the MIMO system model and signal model respectively. Then, the simulation result gathered from the Matlab will be presented and analyzed. The conclusion will be given at the end.
II. SYSTEM MODEL AND SIGNAL MODEL
A. System model Traditionally, wireless communication was designed to use single antenna to transmit and single antenna for receiver. Such system is known as single input single output (SISO) model. However as technology advanced, larger bandwidth, faster speed are required with efficient amount of battery usage. single antennas for transmit and multiple antenna receiver scheme has been implemented known as single input multiple output (SIMO). As schemes such as SIMO has...