Signals Research: Sprint's 8T8R radios in 2.5 GHz increase throughput, coverage

Sprint's (NYSE: S) deployment of 8T8R (eight-branch transmit and eight-branch receive) radios in its 2.5 GHz TDD LTE spectrum is resulting in increased data throughput as well as coverage according to a new report from Signals Research. "Thanks to TM8 [transmission mode 8] and 8T8R, we observed meaningful increases in coverage and spectral efficiency, not to mention overall device throughput," Signals said in its executive summary of the report.

The firm said it extensively tested Sprint's network in the Chicago market using Band 41 (2.5 GHz) and Band 25 (1.9 GHz) in April using Accuver's drive test tools and two Galaxy Note Edge smartphones. Signals tested TM8 vs. non-TM8 performance, Band 41 and Band 25 coverage and performance as well as 8T8R receive vs. 2T2R coverage/performance and stand-alone carrier aggregation.

Sprint has been deploying 8T8R radios in its 2.5 GHz footprint, which the company has said will allow its cell sites to send multiple data streams, achieve better signal strength and increase data throughput and coverage without requiring more bandwidth.

The company also has said it will use carrier aggregation technology to combine TD-LTE and FDD-LTE transmission across all of its spectrum bands. In its fourth quarter 2014 earnings call with investors in February, Sprint CEO Marcelo Claure said implementing carrier aggregation across all Sprint spectrum bands means Sprint eventually will be able to deploy 1900 MHz FDD-LTE for uplink and 2.5 GHz TD-LTE for downlink, and ultimately improve the coverage of 2.5 GHz LTE to levels that its 1900 MHz spectrum currently achieves. Carrier aggregation, which is the most well-known and widely used technique of the LTE Advanced standard, bonds together disparate bands of spectrum to create wider channels and produce more capacity and faster speeds.

Sprint has been criticized for its network, and now Claure is hinting that the company is planning to massively densify its network using its 2.5 GHz spectrum. Called the "Sprint Next Generation Network," the plan calls for a balance of small cells and macrocells and promises an improvement to both network speed and capacity.

Speaking on the company's first-quarter earnings call with investors earlier this month, Claure said that the company has issued a request for proposal from the industry's vendor community and is currently evaluating those proposals. Although he declined to reveal exactly how many small cells and macrocells Sprint is planning to add to its network, he said that the long-term plan will dramatically increase coverage and capacity and over time will include the deployment of Voice over LTE technology. He also said that the new Next Generation Network plan will produce potential cost savings compared to the company's prior Network Vision network modernization plan.

For more:
- see this link to the report

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Correction, June 11, 2015: This article was updated because Signals Research did not test Sprint's 8T8R radios coupled with 4x2 MIMO as originally noted. It just tested the 8T8R radios in 2.5 GHZ TDD LTE spectrum.