While the initial hype may have died down small cells are still very much at the heart of operator strategies for 2014. Julian Bright, Informa’s senior analyst for networks gives us the low down from Informa’s Small Cell Global Congress in Berlin last month on Huawei’s plans for the technology.
The buzz of interest that surrounded small cells in the early days may have subsided, but the evidence is that the majority of vendors and operators remain convinced that the technology has a key role to play in the future mobile broadband network.
The demands of mobile data traffic growth and the associated cost of delivering the required capacity and coverage necessitates a major re-think of conventional architectures, and small cells are one radical solution that can address many of the challenges. Thus most observers agree that it is more a matter of when and where small cells will be deployed, rather than whether they will be deployed at all.
With all the major equipment vendors now committed to small cell technologies in some degree, differentiation increasingly hinges on aspects such as ease and cost of deployment, flexibility in the provision of backhaul, and whether a positive user experience can be achieved given the level of integration required in an increasingly heterogeneous radio environment.
Huawei has made these three elements the focus of its small cell strategy, and at Informa’s Small Cell Global Congress in Berlin last month, fleshed out some of the detail. Having been early to market with its AtomCell outdoor small cell product and LampSite indoor coverage technology, the vendor is already engaged in trials with a number of operators including Vodafone, EE, BT, SFR and SoftBank, as well as with operators in China, and says that it expects to see significant uptake in small cells in 2014.
The vendor saw its shipments of microcell products triple in 2013 compared with 2012 levels, to reach 8,000 units, and expects to see a further doubling in 2014, particularly as the market in China for hotspot and indoor coverage starts to build.
In advanced LTE markets such as Korea, small cells are already providing a capacity layer for hotspot coverage using a dedicated carrier and fibre backhaul, says Huawei. Elsewhere trials using shared carrier (co-channel) deployments of outdoor small cells have shown that these can deliver a comparable improvement in coverage as well as enhanced data capacity, although in the latter case, to a lesser degree than when using a separate carrier.
With 80 per cent of data traffic concentrated in urban hot zones, the combination of small cells and Wi-Fi can provide an ‘onload’ rather than an ‘offload’ solution for operators by creating a broader data pipe, says Huawei, with the mobility and QoS attributes of small cells complementing Wi-Fi’s additional capacity.
In a HetNet environment, the co-ordinated use of network resources contributes to a much-enhanced user experience, says the vendor. For example, through the use of a single radio network controller to co-ordinate and schedule resources for multiple radio access technologies such as GSM, UMTS, LTE and Wi-Fi. Interference control measures can help to improve performance in co-channel deployments, while for indoor deployments the BBU can be shared between indoor radio units and the macro.
Huawei reports that in deployments and trials so far, an improved user experience is already evident through the use of small cells, which is leading to an improved ROI for operators.
Backhaul is generally regarded as the single greatest challenge for small cells, particularly in regard to outdoor small cell deployments in urban settings. Huawei says that flexibility in the choice of technology is an important factor, and street deployments will be the most challenging for operators.
Existing macrocell sites can be leveraged for backhaul aggregation, while Huawei’s eRelay TD-LTE backhaul technology opens up the possibility of re-using spectrum between the access and the backhaul. Whatever the technology, however, support for small cell performance and quality of service requirements is critical.