By the Light of the Silvery Moon

QUANTIFYING THE IMPACT OF 4X2 CL-MIMO IN A COMMERCIAL LTE NETWORK Part of “The Mother of All Network Benchmark Tests” Series of Reports

07/08/2014 | 41 pages
Price: $1,295.00

4x2 CL-MIMO Benchmark Study

With the continued support of Accuver, we leveraged its XCAL drive test solution and its XCAP post-processing software to evaluate the performance of Closed Loop MIMO (CL-MIMO) with a 4×2 antenna configuration – 4 transmit / receive antennas at the cell site and 2 receive antennas in the mobile device.
We compared 4×2 CL-MIMO and 2×2 OL-MIMO, 4×2 CL-MIMO and 4×2 transmit diversity (by getting T-Mobile to “turn off MIMO “ in its network), and the benefits of 4 receive antennas at the cell site.  SRG takes full responsibility for the analysis and conclusions that we provide in this report.

KEY OBSERVATIONS INCLUDE THE FOLLOWING:

• The benefits of 2×20 MHz LTE, a Category 4 smartphone, and 4×2 CL-MIMO cannot be ignored.
- peak data rate of 143.8 Mbps in the downlink (per TTI) and 46.93 Mbps in the uplink (per second)
- The median MAC (Media Access Control) Layer downlink throughput was 36.42 Mbps and the median MAC Layer uplink throughput was 28.15 Mbps – both values include 2×2 OL-MIMO results
- the downlink throughput exceeded 10 Mbps for nearly 95% of the time and the uplink throughput exceeded 10 Mbps for 87% of the time – both values include 2×2 OL-MIMO results
• The clincher for bullish views on a 4×2 cell site configuration appears after we filter the 4×2 and 2×2 results.  
- Substantially higher uplink user data rates, in particular closer to the cell edge
- Far more efficient scheduling of uplink network resources, again when the mobile device was closer to the edge of cell
- A clear indication of improved battery life throughout a large portion of the cell
- Meaningful improvements in downlink data rates near the edge of the cell
• Consistent with our earlier study, 4×2 CL-MIMO delivers strong gains versus transmit diversity for a wide range of network conditions – perhaps even a greater range than we previously observed with 2×2 OL-MIMO.