Mindspeed brings support for smart DAS into Small Cells

DAS has been a traditional way to improve cellular coverage within large buildings, such as shopping malls, offices or airports, by ‘piping’ radio signals over coaxial cables to ensure it reaches all areas. While good for improving coverage, this does not solve today’s problem of data capacity caused by the explosive growth in traffic from smartphones and tablets. In contrast, small cells cost-effectively create capacity and improve service quality for customers, but getting them to cover all areas of a large building can be a challenge. By integrating support for DAS into its SoCs, Mindspeed now enables solutions that combine the two, efficiently delivering both capacity and coverage in these challenging indoor environments.

Until now, chips for small cells have been unable to support DAS but Mindspeed’s PC333 and PC3032 products have added specific support to deal with the delay characteristics of the long coaxial networks and the specific antenna technology associated with DAS. The PC333 and PC3032 are expressly designed for high-performance public access small cells that serve urban hot spots, city centers and dense in-building systems. They are the only small cell SoCs that support 3GPP Local Area Base Station performance and soft handover standards, important in areas which may be served by multiple antennas such as DAS.

“Just as people have found with Wi-Fi, small cells and DAS should be seen as complementary technologies rather than competitive,” said Doug Pulley, chief technology officer, wireless, at Mindspeed. “Combining small cells and DAS opens up new opportunities for both technologies and allows carriers to cost-effectively address both coverage and capacity in large buildings. Many retail complexes and offices have DAS systems installed which enable capacity upgrades and a migration path to 4G. Mindspeed is the only company to support DAS on its chips for small cells, and is leading the industry with new capabilities and creating new opportunities.”

“The combination of DAS and small cells make an extremely good fit, especially in medium sized buildings where there is existing fiber, coax or CAT5 cabling that distributes the RF signals. In many buildings, there is no reason to drive DAS using traditional three-sector macro base stations, but rather to use small cells to drive DAS, possibly on every floor,” says Aditya Kaul, practice director, mobile networks, at ABI Research. Mindspeed is using some clever technology to combine the two, but the benefits are clear: small cells generate coverage from thin air and DAS gets RF where it needs to go. It is critical that in-building systems start to penetrate small and medium sized enterprises and related verticals, and the fact that DAS and small cells can combine forces is proof we are entering a heterogeneous network future.”

Traditional DAS solutions channel radio frequencies and provide excellent coverage for large buildings, underground tunnels, shopping malls and areas difficult to penetrate using outdoor macro cells. Today the biggest challenge facing operators is enabling excellent coverage while maintaining the capacity to support ever-increasing amounts of data. This is where small cells can provide a solution.
Small cells are excellent at delivering capacity. Traditionally, small cells have served an area around a base station (perhaps 100m in a city, up to 2km in a rural area) – this is perfect for providing capacity in busy train stations or congested commercial intersections. It is, however, less suited to the complex network of corridors in a large building, risking that even with the use of small cells there may be coverage shadows or black spots.

By combining small cells with existing DAS installations, carriers can integrate a technology that generates capacity with a technology to channel this capacity effectively. This integration will solve problems for operator and building owners and extend the scope of small cells, while adding new opportunities and new value to companies currently providing traditional DAS solutions.

Support for smart DAS is now available on Mindspeed’s Transcede PC333 and PC3032 SoCs for HSPA+, and will be supported on the company’s dual-mode (HSPA+ and LTE) T2200 and T3300.