Cellular changes

4 mins read

Delivering 4G communications will need a change of mindset from the telecomms sector.

The first half of 2009 has seen a lot of attention given to 4G. While some hype is to be expected, little attention has been paid to the changes that must be made to ease the transition from 3G to 4G. The predictions for 4G performance are impressive, but in order to fully leverage the capabilities, the telecommunications sector must innovate in areas ranging from pricing strategy to network architecture. The term '4G wireless' generally describes the next evolution of cellular communications. 4G systems are capable of delivering bandwidths ranging from 100Mbit/s to 1Gbit/s to each subscriber, promising to make wireless broadband a reality for anyone with a 4G equipped device. While 3G systems delivering up to 1Mbit/s have enticed many workers into connecting from laptops while on the road, 4G will cause an explosion in the number of wireless data users, as well as a rapid acceleration of application development. As a result, we can expect to see increasing enterprise use of mobile applications. Much of the 4G hype is down to changes in the ways in which individuals use their mobile devices. Handsets like the iPhone have led to a dramatic increase in the use of sophisticated data services while on the move. Smartphones have become standard equipment in many companies, allowing workers to stay connected. Now, the industry is buzzing about emerging 4G wireless services. The main technologies being developed for 4G services are WiMAX and 3GPP Long Term Evolution. There is also some interest in WiBro, iBurst and 3GPP2 Ultra Mobile Broadband. As European mobile carriers rolled out 3G and 4G services, they discovered that these often higher frequency and high data rate services required significant restructuring of wireless infrastructure. Data intensive services require more bandwidth per subscriber (and per cell site), in addition to stronger and more localised coverage and capacity to provide the expected quality of service. 3G and 4G also require a different type of radio network architecture, because there are additional challenges in delivering signals and the service usage model will be much different than it was for GSM and 2G systems. While 2G users primarily accessed voice and low bandwidth data services, 3G and 4G users will use far more bandwidth intensive services, such as video. In addition, mobile subscriber use will shift indoors, as users will typically be stationary while using video and other 3G/4G applications for work and leisure. This change in the usage model creates two key challenges for mobile operators. * Insufficient coverage: At frequencies of more than 2GHz, 3G/4G network signals attenuate more quickly than the lower frequencies used in 2G networks. These higher frequency signals do not penetrate through building walls or transit stations well, if at all. Since most high speed data usage will take place in these areas, carriers must find ways to bring signals indoors. * Insufficient capacity: 2G networks were built on the assumption that individual users would access very little data. But broadband wireless services will require much more: perhaps 100Mbit/s per user. Since there is only so much capacity available within any given frequency band, greater capacity must be provided by creating a larger number of smaller cells within the network footprint. Smaller cells, or splitting the current cellular architecture, reduces the user population within a given area and allows for more of the cell's available capacity to be delivered to each of them. 3G rollouts have been in place for a few years and these problems have caused demand to soar for point coverage and capacity solutions to augment macro network coverage inside subways, stadiums, tunnels, network black spots, businesses and even homes. Fundamentally, the 3G wireless era was the last in which mobile operators could rely solely on macro networks fed by large base stations. With a need to service dense populations of users wanting higher bandwidth, operators and enterprises will have to move to a micro network model. Under this model, macro network base stations will be supplemented by smaller base stations or by consolidated base stations – a base station hotel – and user level antenna systems to cover areas where macro networks don't reach. To meet 4G challenges, carriers must not only subdivide macro cells to create smaller ones, but also deploy cells inside buildings. Wireless systems in buildings require distributed antenna systems (DAS), not only to address all areas within the building, but also to deliver multiple operator services as most carriers are supporting two, three or four technologies simultaneously. The DAS will typically be fed by picocells, microcells or femtocells and each operator wishing to provide service through a DAS will need to locate a small base station inside the building or redirect capacity from a nearby base station hotel. In areas where the macro network is lightly loaded, these systems may be fed by a repeater, but this model will not be typical. Thousands of DASs have been sold but, with 4G looming, the real growth in demand is just beginning. Now, carriers are offering, or planning to offer, consumer femtocells to boost wireless coverage inside homes and a number of companies are offering larger picocell and microcell base stations, in building and outdoor DAS products that can serve larger enterprise and public facilities. Micro cellular network technologies address three key issues in 4G networks: coverage; capacity; and backhaul. To provide sufficient coverage, DASs will need to be deployed in greater numbers to reach the user. Companies that already have DAS solutions in their networks will need to add more antennae in more locations than were required for 3G and will need to upgrade their systems to support 4G services. With a need to distribute far more radio capacity to far more locations, wireless operators will have to rely more heavily on their customers to provide adequate backhaul. Consumer oriented femtocells use the customer's DSL or cable broadband connection to backhaul traffic to the operator's network; enterprise class solutions will use a combination of broadband lines leased by the user or the operator. Another option will be the use of high performance microwave or millimetre wave wireless links as the backhaul channel. Carriers have used wireless backhaul for isolated cell towers for years and, now the price and deployment cost of these systems is dropping with the advent of millimetre wave systems, it is likely that more commercial deployments will be seen. While 4G wireless may still be in the future, it is not too early to evaluate the micro network solutions available today. By architecting and deploying these micro networks today, they can be expanded and upgraded when necessary to cope with 4G developments. By planning ahead, today's 2G and 3G services can be improved while creating a solid infrastructure that will support 4G technologies and flexibility for the applications ramp and mobile device advancements of tomorrow.