Rajesh believes that technology disruption from low cost silicon, COTS hardware and smarter software will drive the industry towards a different RAN architecture. He explains why his startup venture Parallel Wireless have adopted this alternative approach, pointing out the advantages of an LTE gateway and mesh interconnected small cells.
Why do you believe an LTE access controller is required?
The 3GPP LTE standards removed the need for a RAN gateway – there is nothing equivalent to the 3G RNC or 2G BSC, and instead all LTE basestations (eNodeBs) connect directly to the core network.
Looking at feedback from early large scale LTE deployments, such as in South Korea, we can see that high volumes of signalling traffic can overwhelm core networks (specifically the MME) leading to poor system performance. This may not show up in small scale trials/early launches but becomes apparent as the system grows. We've witnessed South Korean operators developing their own LTE small cell gateways which consolidate the signalling traffic, reducing the load on the core network, improving call drop/handover rates and enhancing network performance.
Some operators already accept the need for an LTE gateway but only for the larger number of enterprise and residential small cells. They like to see that category of RAN equipment managed separately from the mainstream macrocell network. We believe that in future all LTE cells, both large and small, will be connected through a gateway.
What's driving this increase in signalling storms?
All smartphones are GPS time synchronised these days and many Apps regularly poll at precisely the same time – for example, Facebook every 12 minutes. The resulting traffic isn't randomly distributed but takes the form of synchronised attacks. Buffering and moderating these flows before they reach the MME dampens these storms and moderates their effects. Signalling abuse can also originate for other reasons – I can point to where buggy smartphone software has been known to kill an entire network in the past.
Our LTE Access Controller can filter signalling on a per subscriber or per IMEI (device type) basis to deal with that. The controller also performs a range of other functions including X.2 brokering, SON functions and MOCN (Multiple Operator Core Network) routing. It uses the same standard S1 and X.2 interfaces as all core networks and LTE eNodeBs, and is designed to interwork with all other vendor products.
What's different about your eNodeBs (LTE Small Cells)?
Today's small cell SoCs (Systems on a Chip) provide full baseband capability for less than $100. A single chip or few chips can now do what it used to take a full rack of cellsite equipment to achieve. This changes the game and we believe that much more functionality and capability will be pushed towards the edge of the network.
Our LTE small cells (eNodeBs) are quick and simple to deploy, being provisioned and optimised by the LTE Access Controller. Uniquely, we have developed a direct wireless connection between the small cells – this uses out of band licenced or unlicensed spectrum to reduce the need for separate backhaul at every location. The nodes automatically configure into a mesh network, routing the backhaul traffic through available links to the nearest/most appropriate wired backhaul point.
The mesh radio link uses a proprietary peer-to-peer multipoint-to-multipoint protocol, FDD transmission, with very low latency. Any eNodeB can also have a traditional Ethernet backhaul connection, those that don't route traffic via the mesh, which automatically adapts to outages, moves and changes.
Any particular target markets you're aiming for first?
We see a significant opportunity for Public Safety LTE networks used by first responders such as police, fire, ambulance etc. Some band 14 spectrum (~700MHz) has been set aside for this purpose in the US. Our system would allow them to deploy their own networks quickly and with added resilience.
This is also true for temporary networks setup for specific incidents where a small cell could provide local service and co-exist with the existing macro network.
We've focussed on outdoor products first, for urban and rural applications. Our CWS-100 small cell is a very simple to deploy unit and is currently undergoing commercial trials with several network operators.
Disclaimer: Parallel Wireless is a sponsor of ThinkSmallCell
For more information about Parallel Wireless, visit their website at parallelwireless.com