The plethora of different Small Cell vendors (for example 10 mostly new entrants have recently been selected by China Mobile) masks the situation that there are relatively fewer vendors of Small Cell gateways. These could become the gatekeepers for an increasing range of suppliers, either opening up the market or constraining it. We survey the market and evaluate the tradeoffs.
2G, 3G and LTE Small Cell Gateways
Each generation of technology has its own architecture. 2G and 3G definitely need their own respective gateways to interwork between different protocols such as Iu-h to Iu.
LTE technically doesn’t, and you can avoid using one for small scale trials (say anything up to 1,000 small cells). Larger deployments benefit from optimising the signalling traffic, offloading from the core network and streamlining handovers. As a result, voice call drop rates are reduced and seamless data service is improved.
These gateways are normally (but not always) located in the core and aren’t the same as the local controllers deployed in-building for systems such as Spidercloud or Airvana, or Centralised RAN controllers such as Airspan's AirSymphony.
Current Small Cell Gateway vendors
The following list (in alphabetical order) makes no judgement as to the maturity, suitability or scalability of any of the products listed. It may not be complete but is indicative of the general playing field. Please comment below with corrections or clarification.
CASA systems are a relative newcomer and less well known to the Small Cell scene, but are already major suppliers to wireline and Cable networks. They’ve been visible at the ETSI interworking plugfests and are known to be very active in trials in China and elsewhere. Their Axyom gateway can be deployed near to the network edge (for example at CableTV head-ends) and combines functions for 3G, LTE and Wi-Fi as well as data caching.
Cisco have demonstrated the scalability of their ASR 5000 Series Small Cell Gateway with a deployment exceeding 1 million small cells at AT&T. They’ve been regular participants at the ETSI interoperability plugfests, ensuring their system interworks with many other small cell vendors. Their solution supports 3G, LTE and Wi-Fi.
Contela have been in the Small Cell business for many years, with both 3G and LTE end-to-end solutions that includes a gateway.
ip.access are one of the few (possibly the only) with a GSM small cell gateway. They’ve continuously extended the functionality to incorporate 3G and LTE over time, with three different products on offer. nanoConverge uses a single rack can host a mix of all three simultaneously, sharing the same provisioning and management system. nanoGW300 is a high capacity 3G gateway, and nanoGW200 is a lower cost, scaled down product for 2G/3G.
NEC have gained tremendous experience from many field trials and several large scale deployments worldwide, having supported both Ubiquisys and Spidercloud for many years. Their solution was upgraded to include LTE in 2014.
Nokia, who acquired Alcatel-Lucent in January, have inherited their small cell gateway which they have retained and promote as part of their femtocell solution. Alcatel-Lucent’s approach has included several proprietary enhancements from the standard interface specifications, which suggest it may not interwork quite so well with other vendor’s small cells, but their small cell hardware design is available for other manufacturers to use. The gateway supports both 3G and LTE.
Parallel Wireless combine not just 3G and LTE but also a Carrier Wi-Fi gateway in their HetNet Gateway. This enables seamless handover to/from Wi-Fi, multi-technology SON. A virtualised architecture is used to ensure the solution is highly scalable. They are very open to interworking and supporting small cell products from other vendors.
Samsung, who have large deployments of CDMA Femtocells also now offer LTE. Their end-to-end portfolio includes a Small Cell gateway
Other perhaps less well known gateways include those from
- ASTRI, perhaps considered more as a software vendor rather than a fully independent gateway product
- Fujitsu, LS700 gateway supporting their own range of LTE small cells
- Hitachi, primarily supporting their own range of LTE small cells
- Polaris Networks advertise an LTE gateway in their portfolio, targeted for smaller, standalone applications.
- Ruckus Wireless: Announced the SmartCell 200, an evolution of their (Wi-Fi) Wireless Service Gateway which will support their own MuLTeFire LTE small cells.
- SK Telecom pioneered their own LTE small cell gateway not intended for sale elsewhere. We interviewed an SK Telecom senior manager to discuss it in 2013.
- ZyXel. A major supplier of residential Femtocells through partnership with Alcatel-Lucent and others, this vendor also offers their own FGW1000 residential femtocell gateway.
I can find no public information online about Huawei, Ericsson or ZTE gateways. Huawei did have a 3G gateway some years ago when they developed 3G residential Femtocells, but later withdrew. Ericsson doesn’t advertise a gateway and would directly connect their RBS picocells and Radio DOT solution into the core network.
Interoperability is key
ETSI plugfests have been quite popular and shown high level of success. An extensive report of their 2014 session indicates quite thorough activity.
Future scope includes SON
SK Telecom demonstrated some years ago that the LTE gateway is a good location to place SON functions. They developed an auxiliary SON server that was co-located with and interwork directly through the gateway.
Several of the gateway vendors listed above have followed that path, adding SON, traffic management and handover optimisation features.
It seems to me to be highly likely that we’ll see growing intelligence and co-ordination at these multi-technology gateways, using load balancing and seamless handoff to make best use of available radio capacities across all HetNet resources.
Integration and Deployment
Network operators are making a major decision when adding any new RAN vendor into their network. There are considerable implications in everything from procurement, equipment warehousing and supply chain, technical training, operations management, planning and lifecycle management. With typically just two or three vendors in the entire network, adding several more is seen as a huge task.
What we’ve seen from China Mobile is that if the specification and management of small cells is carefully defined and tested, then there may be relatively little difference between each vendor’s product from an operational management viewpoint. There is a single larger integration project to install and integrate the small cell gateway. Selection of perhaps two or three such vendors for the whole network may be enough, opening the opportunity to introduce a larger number of supported small cell vendors in the future.
This makes it important that small cell gateways are widely interoperable with many other small cell vendors and not just locked down to one or two. Open interfaces and proven interoperability will be key.