Modernizing GSM networks – Spectrum sharing (LTE and GSM), Self-organizing Networks (SON) and Beamforming

GSM has turned 24 this year and throughout this time showed that it is invaluable for telephone calls and M2M applications. Many industry observers estimate that 2G will continue to be in use even after 3G is discontinued. But GSM networks are confronted with the difficult task of adapting to the new operating environments.

The modernization of GSM is particularly arduous when considering that equipment vendors and solutions providers have concentrated on developing components for newer networks (3G, 4G, even 5G) and less on innovating GSM network components. The SatSite is designed to serve either GSM, LTE, or mixed GSM/LTE networks working directly with the unified core YateUCN, proving that there’s still plenty of room for innovative results for GSM deployments.

The technology behind our GSM network equipment allows new techniques like radio resource sharing with LTE, running GSM from a remote radio head, applying SON or beamforming technologies, which are typical for LTE, to be applied to 2G networks. The result is a simplified and flexible network architecture, better management and reduced costs.

Spectrum sharing, Self Organized Networks (SON) and Beamforming

Spectrum sharing

The SatSite base station is based on commodity, off-the shelf,-hardware and can be software-‘switched’ to provide either GSM, LTE, or both. When running YateBTS for GSM, it communicates directly with the unified core network, eliminating the base station controller (BSC). This architecture, where the BTS connects straight to the core network and communicates to other BTS in the network over peering protocols is very similar to the architecture of LTE.

This is also what makes it possible to support multiple technologies in the same equipment. If one BTS uses the same frequency bands to provide both GSM and LTE access, operators may choose freely on how to allocate spectrum between them. Depending on the service use at a given time, operators can assign prioritize voice over data services and vice versa. We’ve detailed spectrum sharing between GSM and LTE in the SatSite here.

Self-Organizing Network

SON techniques feature dynamic self-configuration, self-optimization, and self-healing functions, which can be achieved due to the eNodeB not being controlled by a distinct BSC component as in the typical case of GSM. Without a BSC, SatSite base stations are able to connect to each other over peering protocols, allowing an exchange of neighbor information between units. This presentation offers more details on SON technology for mixed 2G/4G networks.

Beamforming

Beamforming relies on grouping the signals of multiple antennas and into one beam sent to a desired direction. It aims to reduce interference and obtain a better quality of a service for a certain user. Unlike MIMO, where the network sends different parts of the data stream on different antennas, beamforming combines the signals from the different antennas and sends them to one device. What’s more, as opposed to MIMO, beamforming does not require any support from the handset, making it suitable for use in any mobile network technology, be it 2G, 3G, 4G or even 5G, in the future.

Benefits of optimizing GSM networks include a better management of the network resources, reduced infrastructure costs and maintenance efforts, and the flexibility to upgrade or reprogram network functions.