Gateway to 5th Generation Mobile Networks - 5G

The demand for e-learning, multi-media services, faster wireless internet access has been increasing rapidly, with the effect there has been a tremendous growth in the number of wireless devices and connections. A high throughput is needed by each device to support applications such as video, voice, games and movies. As per Cisco Visual Networking index, it is expected that mobile data traffic will increase to 24.3 Exabyte per month by 2019. Also, the number of mobile connections will grow to 11.5 billion by 2019. The huge data demand will strain the available network capacity of current third generation (3G) or fourth generation (4G) systems in no time and thus network service providers will face the challenge of providing high data rate, high energy efficiency, increased network capacity and high mobility. In order to fulfill such mounting data demand, the cellular market is heading towards fifth generation (5G) wireless communication systems.

Basic frame work of 5G network to feature:-

Multiple Antenna System - Massive MIMO

Multiple-input multiple-output (MIMO) technology has been recognized as a prime feature of advanced cellular networks during the last two decades. Now, the focus has been shifted to multi-user MIMO (MU-MIMO) systems in which numerous users communicate with multiple antennas (less than 10) deployed at a base station (BS). This technology is further scaled up to its true potential by introducing very large array of antennas with 100 or more radiating elements at the base station for applications in next generation (fifth generation) wireless systems known as Massive MIMO. Massive MIMO is a promising technology for fifth generation wireless systems.

A massive MIMO system

Cooperative Communication

Cooperative communication is a promising technology in which different wireless nodes help each other in forwarding messages to their intended recipients. In a relay-based multihop cooperative wireless network, one or more relays forward a message from the source to the destination as shown in figure below. It is seen that employing more relay nodes between source and destination helps improve performance. Some of the advantages of cooperative communication are increase in data transmission rate, reduction in transmission power, reduction in delay across network, improvement in frequency reuse, expansion of network coverage.

Cooperative Communication

Antenna Selection

Multiple antenna technology provides the benefits of spatial multiplexing and diversity. But the RF chains which consist of components such as an analog-to-digital converter (ADC), filters, mixers, converters associated with multiple antennas add to the cost and complexity. Antenna selection (AS) provides a solution which is less complex in hardware. In receive AS, it is seen that all the antennas employed at the receiver are not used for receiving and processing of signals. Instead, a subset of antennas with the best instantaneous channel conditions to the transmitter is dynamically selected and the signals are processed only through them. Thus, few number of radio frequency (RF) chains are employed by the receiver. Similarly, in transmit AS, the number of RF chains employed by the transmitter is lesser than the available number of antennas. Thus, antenna selection helps in reducing the hardware cost and complexity. Antenna selection in massive MIMO will provide a gateway for 5G wireless communication systems in the days to come.

Joint Transmit and Receive Antenna Selection.

-By Ashu Taneja, Assistant Professor (ECE),
Chitkara University,Himachal Pradesh