Eight is Enough
Eight is Enough
Quantifying The Benefits of an 8 Branch Transmit And Receive Antenna Configuration with TM8 In A Commercial LTE TDD Network
05/28/2015 | 44 pages
Analysis of LTE TDD with carrier aggregation, 8-branch antennas and TM8
We used Accuver’s XCAL-M drive test solution and XCAP post-processing software to conduct a performance analysis of Sprint’s commercial LTE TDD network, including carrier aggregation (CA), an 8-branch transmit and receive antenna architecture (8T8R), and Transmission Mode 8 (TM8).
WE DISCUSS THE FOLLOWING:
- If LTE TDD is going to be a success then it must address the inherent coverage-related challenges that exist in the range of frequencies bands where unpaired spectrum resides. Tricks of the trade, including 8-branch transmit and receive antenna architectures, as well as TM8 (beamforming) were designed specifically for this purpose, but history suggests that technology enablers, such as beamforming, do not always perform as anticipated.
- We used two Galaxy Note Edge smartphones to benchmark the performance of Sprint’s LTE (FDD – Band 25 and TDD – Band 41) network in the greater Chicago area, and more importantly, to evaluate the incremental benefits (if any) of 8T8R and TM8 in a commercial LTE TDD network. Samsung is the RAN infrastructure supplier in this market.
- We made configuration changes to the smartphones and to the network to perform comparative studies, including: single device CA testing with TM8 enabled, concurrent device testing with TM8 versus non-TM8 (both with CA and without CA), as well as with 8T8R versus 2T2R, and Band 41 versus Band 25.
- Fortunately, we observed meaningful increases in coverage and spectral efficiency, not to mention overall device throughput with TM8 and 8T8R, compared with a more basic transmission mode (TM3) and 2T2R.
- We quantify these performance gains across a range of network conditions as well as in aggregate, and provide a wealth of supporting documentation and analysis in the main body of the report.