ATCA Gateway-on-a-Blade Finds a Surprise Home in GSM BSC Upgrades By Rob Pettigrew, marketing director and Brian Carr, strategic marketing manager, Embedded Computing, Emerson Network Power

There’s certainly lots of buzz in the telecom world about next-generation 3G+ and 4G LTE wireless networks. Carriers are deploying these networks to keep up with the insatiable consumer demand for ever increasing bandwidth. But another trend that is also occurring is that the 2G CDMA and GSM networks are being maintained much longer than originally anticipated, and are even finding new applications in rural deployments to bring simple voice communications to areas previously outside mobile or land-line coverage.

This is partly because these 2G networks are based on older circuit-switched data streams and hence are cost- and power-effective for simple voice communications and SMS text messaging, requiring only simple handsets to participate. In contrast, the next-generation 4G networks are based on flat IP out to the mobile units and so are strictly for data only. In fact, voice on a 4G network is carried as VoIP straight from the mobile device and then treated as just another data service.

The base station controller (BSC) is one of the main control functions that 2G network operators require to be scalable. In a GSM network, the BSC is the device that interfaces directly to and manages the base stations (BTS), typically across multiple E1 lines. On the other side of the BSC, it interfaces to a transcoder and rate adaptation unit (TRAU) to convert the voice signal between the codec used on the mobile handset and the standard voice coding schemes used in the traditional telephone network. It also interfaces directly to the mobile switching center (MSC) for call signaling and, via a packet control unit (PCU), the packet data network for IP communications to the Internet. Depending on the network topology, a BSC can manage hundreds of base stations, so optical SONET/SDH connections are often used to aggregate all the E1 lines into higher capacity multiplexes.

Having completed several customer workshops recently, we have identified that combining the BSC and TRAU function can lead to cost and space savings, especially for smaller network topologies. A combined BSC and TRAU function can be considered as a combination of:

TDM line terminations A bank of digital signal processors (DSPs) for transcoding Processing capability for signaling and control plane An operations and management (OAM) unit

Caption: The ATCA-8310 ATCA blade from Emerson Network Power features TDM line terminations linked to a scalable DSP bank, an eight-core Power Architecture™ processor (Freescale QorIQ™ P4080) that can be used for signaling and control plane, and a dual-core x86 processor (Intel® Core™ i7) for running OAM or user applications all on the same board.

Enter the “gateway-on-a-blade” approach. Originally conceived for media gateway applications, this blade is an ideal basis around which to build a new BSC. It gives the lowest possible cost and size for entry-level redundant systems, and provides a substantial ease-of-integration advantage over solutions that rely on separate boards or AMC modules to perform individual functions. Signaling and control plane performance to handle more base stations or higher traffic can be increased by the addition of processor blades, such as Emerson’s ATCA-7365.

The result is that an element that used to occupy a cabinet of gear can now be implemented in a six-slot ATCA shelf!

Bios:Robert Pettigrew is director of marketing for the communications market with the embedded computing business of Emerson Network Power. In this role, he is responsible for product strategy and customer business engagement for customers in the telecommunications and data communications markets. Pettigrew received his bachelor’s degree in engineering physics from the University of Saskatchewan and a master’s degree in engineering science, specializing in digital speech coding, from Simon Fraser University.

Brian Carr is strategic marketing manager for the embedded computing business of Emerson Network Power. He aligns market and application insight with technology advances to direct the company’s strategic AdvancedTCA roadmap. A widely published author and accomplished speaker on AdvancedTCA technology and applications, Carr has also represented Emerson on conference advisory boards and industry consortia. He holds master’s degrees in engineering from Cambridge University and in information technology from Essex University.

Pull quote: Although there’s lots of talk around 4G, and operators need to be prepared for that, there’s also still a lot of 2G and 3G infrastructure being built and they need to be thinking about current needs as well as future.

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