A group of companies spearheaded by Qualcomm is proposing a standard called Direct LTE, which would allow the technology to be used for short range, peer-to-peer links between devices.
Connecting products on an ad hoc basis, without an access point, has mainly been the preserve of the unlicensed standards ‘ Bluetooth and Wi-Fi. The most recent approach, Wi-Fi Direct, is being heavily supported in the current wave of consumer WLan chips and devices.
But while the technical challenges of achieving peer-to-peer links using LTE are more complex than for Wi-Fi, firms like Qualcomm have an interest in harnessing the 4G system for almost any application. Other supporters include Alcatel-Lucent, Deutsche Telekom, LG, NEC and Nokia.
And Mahesh Makhijani, a technical director director at Qualcomm, told last week’s NGMN Alliance conference that LTE could discover nearby users more quickly, and with less processing overhead, than Wi-Fi Direct or GPS.
However, he sees the various technologies as complementary, since most devices will support all three in future. For instance, he thinks that, in certain scenarios, it would be quicker to discover a nearby user with LTE, but data might then be sent via Wi-Fi Direct to save on network costs and burden.
In particular, the group supporting Direct LTE are focused on location-aware applications, and particularly on boosting power efficiency. Direct LTE could support ‘proximity services that provide more value to the mobile network,’ said Makhijani, pointing to emerging applications which rely on ‘ambient awareness’, such as FourSquare and Twitter Discovery.
The technology would support line of sight connections over distances of up to 500 meters and with 20-23dBm signaling limits. In internal tests, Qualcomm said the technique discovered as many as 7,200 terminals in 0.64 seconds, compared to 369 terminals found with Wi-Fi Direct in 82 to 119 seconds. Makhijani told the conference, as reported by EETimes, that his firm had also found that latency for Wi-Fi Direct discovery degraded significantly as device density increased.
The new group wants to submit Direct LTE to the 3GPP for inclusion in LTE Release 12, scheduled to be available in 2015, and it may also look to define its own ad hoc standards in order to get into devices at an earlier stage.