Wang et al. published an article about some of the key technologies of 5G cellular network in IEEE communications magazine, titled “Cellular architecture and key technologies for 5G wireless communication networks”. Major technologies discussed in the articles include a new heterogeneous 5G cellular architecture, some key technologies that can be implemented into 5G to improve performance, and some future challenges.
The article proposes the next-generation wireless communication technology 5G needs to be constructed in a new type of heterogeneous cellular architecture to achieve maximum, seamless coverage and high mobility. The new architecture will be separate indoor and outdoor access point because of the short-range RF (Radio Frequency) spectra of 5G. Outdoor base stations will be equipped with large antenna arrays. These antennae will connect to wireless access point inside buildings for indoor users. This will solve the short-range and penetration loss through walls issue. Not just stationary wireless communication has issues that need to be addressed, high mobility wireless communication also. According to Wang et al., “High-speed trains can easily reach 350 up to 500km/h, while 4G networks can only support communication scenarios up to 250 km/h” (Wang et al., 2014, p.123). The MFemtocell (Mobile Femtocell) concept, which combines the concepts of mobile relay and femtocell, is proposed to accommodate high mobility uses such as users in vehicles and highspeed trains. Access points can be deployed inside highspeed transportation. Instead of communicating directly to outdoor base stations, devices will be connecting to access points inside of these highspeed transportations.
Some key technologies have mentioned in the article that can improve the performance and power efficiency of 5G system. They are the following. Massive MIMO (Multiple Input Multiple Output) systems, by adding more antennae to a MIMO system to increase performance, reliability, spectral efficiency, and energy efficiency. SM (Spatial Modulation), a MIMO technique for low-complexity implementation of MIMO system. It can mitigate interchannel interference, interantanna synchronization, and multiple RF chains in conventional MIMO systems. This technique can be used in MIMO system with any number of transmit and receive antennae, even unbalanced MIMO system. CR (Cognitive Radio) network, an innovative software technology to improve the utilization of the RF spectrum. A large portion of the radio spectrum is underutilized most of the time, a CR network can detect, share, and use these spectrums when the system is loaded. Another viable technique that helps mitigate spectrum bottlenecks in RF communication is VLC (Visible Light Communication), which uses LED light as a signal transmitter. It can be implemented using the current lighting infrastructures.
Many technologies have proposed and discussed in this article, but there are still many challenges needs to be addressed. Such as realistic channel models for 5G wireless systems, reducing signal processing complexity for Massive MIMO, interference management for CR networks, and more importantly, green communications. A tremendous amount of base stations will be deployed in the 5G era because of the short-range signal. Performance is admittedly important, but it also needs to be energy efficient to reduce CO2 emission.
Wang, C. X., Haider, F., Gao, X., You, X. H., Yang, Y., Yuan, D., … & Hepsaydir, E. (2014). Cellular architecture and key technologies for 5G wireless communication networks. IEEE communications magazine, 52(2), 122-130.