Methods and systems for downlink flow control in a wireless communication system

摘要

Methods and apparatus for downlink rate control by a user equipment (UE) (e.g., when an overload condition happens at the UE) are provided. For example, the UE may experience CPU overload, CPU near-overload, memory overload, memory near-overload, overheating or near-overheating. For certain aspects, the UE may simulate a “degraded channel” in order to cause an eNodeB to lower a transmission rate or block-size as it would in response to receiving an indication of bad channel conditions. The UE may simulate a degraded channel by modifying a channel quality indicator (CQI) and transmitting negative acknowledgment (NACK) messages to the eNodeB. Therefore, the eNodeB may be responsible for guaranteeing quality of service (QoS) based on the new degraded channel condition. In other aspects, UE downlink flow control is achieved by dropping hybrid automatic repeat request (HARM) packets or reducing a radio link control (RLC) receive window size when an overload condition occurs.

主权项

1. A method for wireless communications, comprising:
receiving a packet from an apparatus through a channel; determining an advertised channel quality indicator (CQI) value indicating information regarding a degraded channel when an overload condition happens, wherein the advertised CQI value is determined based on at least one of an actual CQI of the channel, a target flow rate or channel bandwidth; determining a modified acknowledgment message based at least on the advertised CQI and an actual acknowledgment message, wherein the actual acknowledgment message indicates whether or not the packet is received correctly, wherein determining the modified acknowledgment message comprises setting the modified acknowledgment message to a NACK (negative acknowledgment) based on a probability even if the actual acknowledgment message is set to an ACK (acknowledgment), wherein the probability is determined based on one or more of an average flow rate, the target flow rate and a hysteresis margin, and wherein the average flow rate corresponds to a hybrid automatic repeat request (HARQ) error rate during normal operation; and transmitting the advertised CQI and the modified acknowledgment message to the apparatus to adjust flow rate of future transmissions.