An emerging technology is a chance for individual vendors to showcase their talents and raise their profile, and the same goes for countries or regions, all aiming to be the next Silicon Valley. In the UK, the main contenders are the areas around the cities of Cambridge ('Silicon Fen') and Bristol ('Silicon Gorge'), and both have been using LTE to show off their credentials this week.
Cambridge Consultants is claiming a breakthrough in improving LTE uplink performance, without any changes needed to handsets. This is done with its Duel (Dual-Domain Uplink Equalizer for LTE) receiver technology, an alternative to the conventional receiver design, MMSE. Duel is implemented as an extension to LTE base station receiver designs, providing a set of "unique and highly complex algorithms" that generally run on DSPs, but can also be deployed on FPGAs or ASICs. No changes at the device end are required to gain the performance benefits.
Uplink performance is increasingly important as mobile internet usage patterns shift from downloading of web information to two-way communication and content generation. But as with all mobile platforms, LTE uplink remains significantly slower than downlink and the high data transfer rates promised by LTE require ideal channel conditions, such as low mobility or high diversity.
Duel, says Cambridge Consultants, improves uplink performance in all channel conditions, by better exploiting the inherent advantages of LTE's uplink technology,
SC-FDMA, which the firm told Mobile Today is the area where the technology is most novel (and most different from its fellow OFDMA-based system WiMAX). It has developed a test platform that includes a conventional MMSE receiver alongside the Duel device to allow their performance to be compared on the same received signal. The test system uses a combination of devices from Cambridge Consultants' proprietary Viper development platform and from partner picoChip.
picoChip, itself part of the Silicon Gorge community, is also partnering with another UK neigbor, Lime Microsystems, on an LTE-focused advance. The femtocell silicon leader has collaborated with Lime, a specialist in RF transceivers that work across a wide range of frequencies, on a reference platform for 3G and 4G femtocells. The design, which will be available in the first quarter of 2010, will support HSPA, CDMA2000, LTE and WiMAX. It will use the Lime LMS6002 multiband, multi-standard RF transceiver chip - which can operate between 375MHz and 4GHz - and the picoChip picoXcell baseband.
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