1. On TX EVM Date: 2017-09-11 Authors: September 2017 Month Year
doc.: IEEE yy/xxxxr0
September 2017
On TX EVM
Date:
Authors:
Ron Porat (Broadcom)
John Doe, Some Company

2. September 2017
Discussion
The current EVM table is designed for worst case scenarios. Recent amendments have been adding higher and higher MCS levels and requiring lower and lower EVM values (down to -35dB for 1024QAM).
However in many scenarios these values are too low, primarily in scenarios using many antennas (e.g 4 or 8) with Tx beamforming and a strong code (LDPC).
In those scenarios the Tx ends up backing off the PA too much which results in lower MCS than what could be achievable with lower PA backoff and higher Tx power.
Each configuration and transmission mode will have an optimal PA backoff/ EVM value to achieve the optimum rate
Ron Porat (Broadcom)

3. September 2017
Proposal
In order to optimize the link we propose to add the following note to the EVM table that allows the Tx to exceed those values in some cases. No Rx special processing or feedback is required beyond the usual ACKs. The Tx can incorporate power adjustments as part of its link adaptation algorithm.
Proposed Note: When transmit beamforming is used, the Tx is allowed to exceed the required EVM values in the table, by increasing transmit power within regulatory limits, in order to optimize the link throughput
Ron Porat (Broadcom)

4. September 2017
Straw poll #1
Do you support adding the note shown in slide 3 at the bottom of table 28-44? Y N A
Ron Porat (Broadcom)