Adaptive physical layer warm-up for LTE TDD C-DRX power optimization

摘要

Methods and apparatus to reduce power consumption in user equipment (UE) that operates in a connected discontinuous reception (C-DRX) mode while in communication with wireless network are disclosed. A C-DRX warm-up period before the UE enters an on-duration is adjusted dynamically based on one or more factors including a time division duplex (TDD) uplink/downlink (UL/DL) subframe configuration, signal-to-noise ratio (SNR) values, and Doppler shift values. The C-DRX warm-up period is adapted based on the pattern of DL subframes in the UL/DL subframe configuration by including DL subframes that best contribute to channel estimation and adaptive tracking loops based on measured SNR and Doppler shift conditions. Favorable channel conditions, such as higher SNR and lower Doppler shift, can require fewer DL subframes and consequently shorter C-DRX warm-up periods. Higher Doppler shift values indicate more rapidly varying channel conditions and require DL subframes positioned closer to the start of the on-duration.

主权项

1. A method for reducing power consumption by a user equipment (UE) operating in a connected discontinuous reception (C-DRX) mode in communication with a Long Term Evolution Time Division Duplex (LTE TDD) wireless network by determining a length of a C-DRX warm-up period, the method comprising:
at the UE:
receiving from and transmitting to the LTE TDD wireless network a plurality of subframes comprising a sequence of one or more downlink subframes, one or more uplink subframes, and one or more special subframes via a communication channel;determining an LTE TDD uplink/downlink (UL/DL) subframe configuration based on the plurality of subframes;measuring a signal-to-noise ratio (SNR) value and a Doppler shift value of the communication channel between the UE and the LTE TDD wireless network;obtaining a first SNR threshold value and a second SNR threshold value, wherein the first SNR threshold value is less than the second SNR threshold value;obtaining a first Doppler shift threshold value and a second Doppler shift threshold value, wherein the first Doppler shift threshold value is less than the second Doppler shift threshold value;selecting a technique to determine a number of subframes included in the C-DRX warm-up period based on: (i) comparing the measured SNR value with the SNR threshold values, (ii) comparing the measured Doppler shift value with the Doppler shift threshold values, and (iii) the LTE TDD UL/DL subframe configuration; andexecuting the selected technique to determine the length of the C-DRX warm-up period.