Controlling uplink multi-antenna transmissions in a telecommunication system

A method, for use in a base station, of controlling user equipment configured for multi-antenna transmissions in a telecommunication system, the method comprising:

• transmitting, on a downlink channel to a user equipment, first pre-coding vector information indicating a first pre-coding vector for uplink transmission, and subsequently transmitting, on the downlink channel, second pre-coding vector information indicating a second pre-coding vector for uplink transmission;
• determining whether reception quality of the downlink channel is insufficient by monitoring a first relative phase difference between a first pilot signal received from the user equipment during a first time interval associated with the first pre-coding vector information and a second pilot signal received from the user equipment during a second time interval associated with the second pre-coding vector information and by comparing the first relative phase to a second relative phase difference between the first pre-coding vector and the second pre-coding vector.

A base station for controlling user equipment configured for multi-antenna transmissions in a telecommunication system, wherein the base station is configured to:

• transmit, on a downlink channel to a user equipment, first pre-coding vector information indicating a first pre-coding vector for uplink transmission and subsequently transmit, on the downlink channel, second pre-coding vector information indicating a second pre-coding vector for uplink transmission;
• determine whether reception quality of the downlink channel is insufficient by monitoring a first relative phase difference between a first pilot signal received from the user equipment during a first time interval associated with the first pre-coding vector information and a second pilot signal received from the user equipment during a second time interval associated with the second pre-coding vector information and by comparing the first relative phase difference to a second relative phase difference between the first pre-coding vector and the second pre-coding vector.