Chapter 3
Advanced Wireless Technology
Multiple-input multiple-output (MIMO) technology, with multiple antennas at the transmitter and the receiver, can greatly enhance the capacity and performance of wireless communication systems. In addition, MIMO technology has been integrated with many OFDM communication systems to form the backbone of many wireless communication standards. On the other hand, multiple-access schemes enable resource sharing of a communication link among many users. Both of them are essential for the success and widespread acceptance of digital communication systems.
3.1 Multiple-Input Multiple-Output (MIMO)
3.1.1 Introduction
According to the number of transmit (TX) antennas and the number of receive (RX) antennas, wireless systems can be classified as single-input single-output (SISO), single-input multiple-output (SIMO), multiple-input single-output (MISO), and multiple-input multiple-output (MIMO) systems, where the input and output are with respect to the channel between the transmitter and the receiver, as shown in Figure 3.1. The advantages of employing multiple antennas and related signal processing include [1, 2]:
Figure 3.1 Illustration of transmitters/receivers with different antenna configurations.
- Array gain As multiple copies of the signals are received at a receiver with more than one antenna, the signals can be combined coherently to achieve ...
