Carrier aggregation is picking up speed. Several test companies have now announced submissions for validation and other testing for the eagerly anticipated LTE-Advanced feature. The first LTE-A device supporting CA was announced this week, when Qualcomm revealed that its Snapdragon chip is powering the first LTE-Advanced device with carrier aggregation, a new version of the Samsung Galaxy S4 to be released with three Korean carriers.
Carrier aggregation combines radio channels within and across bands (intra-band and inter-band) to increase user data rates, with expected downlink throughput speeds of up to 150 megabits per second.
Anritsu announced this week that it made its first CA test case submissions to 3GPP’s RAN Working Group 5, on the heels of Anite’s announcement last week that it was the first company to submit CA protocol tests to RAN 5. Anritsu says it was the first to validate RF conformance test cases for CA with PTCRB.
Meanwhile, Spirent is now supporting LTE-Advanced testing on its CS8 equipment, including intra-band and inter-band CA, along with 2×2 MIMO, 4×2 MIMO for each carrier, cross-carrier scheduling, integrated independent fading and added noise for each component carrier.
With impending device deployment abroad and domestically, “now is the crunch time as far as getting it all working,” said Brock Butler, marketing director for Spirent.
Butler said that rather than focus on protocol tests, Spirent has been working on interoperability testing and supporting R&D to help its customers de-bug their CA products.
“We do want ultimately to be able to qualify what the end user experience is with this technology,” Butler said.
“It’s very challenging to be talking and listening at two different frequency bands at the same time,” he added. “That has a big impact on things, changes that are going to affect the cost of mobile phones, the battery life. If it doesn’t work right … the benefits you get from carrier aggregation will go away.”
Part of the challenge, Butler said, is that LTE devices must already support as many as 15 or so bands across all of an operator’s wireless technologies — and that’s relying on one band at a time for active communication. With the advent of CA, devices have to support multiple bands, and multiple combinations of bands for aggregation.
“That means more power amplifiers and different receiver designs than we’ve ever had in the past,” Butler said. “Companies have had to be extremely innovative to meet this challenge. The first designs that we’ve seen, they’re probably not optimal. They’re going to have multiple power amplifiers, battery life may be reduced, and they may not be as efficient as they could be.”
Among the winners of the LTE Awards 2013 from the LTE World Summit was Actix. Its Actix Customer Experience Geo-Location for LTE won for the best LTE test and measurement product. Actix has also released a state of the network report earlier this year, and said that there is “no safety net” for LTE deployments, given the high amount of traffic already generated by LTE-ready devices on 3G networks.
Also from the LTE World Summit, PCTEL demonstrated its SeeHawk In-Building Test Suite for carriers, neutral host providers, venue owners, DAS integrators and RF engineers.
PCTEL said that its network engineers used the SeeHawk IBTS on a recent service project at a Texas convention center and were able to collect and report data from 39 different band/channel combos simultaneously across the four national carriers and MetroPCS. Using a conventional solution, according to the company, would’ve taken as much as four times longer to collect the same data.
