Adaptive transmission mode switching

摘要

A node (28) of a radio access network (20) communicates over a radio interface (32) with a wireless terminal (30). The node (28) comprises a transmitter (34) and a controller (40). The transmitter (34) selectively operates in plural multiple input multiple output (MIMO) modes for downlink transmission over the radio interface (32). The controller (40) uses both a terminal speed value and a throughput value to make a determination when to switch between the plural multiple input multiple output (MIMO) modes for communicating with the wireless terminal. The plural MIMO modes comprise a first mode and a second mode. In the first mode open loop MIMO operates with cyclical diversity delay. In the second mode open loop MIMO operates without cyclical diversity delay. Although operating in open loop MIMO, advantages such as those of closed loop MIMO are realized.

主权项

1. A method of operating a node of a radio access network which communicates over a radio interface with a wireless terminal, the method comprising:
obtaining, by the node, a terminal speed value of the wireless terminal; determining to switch between a first transmission mode for communicating with the wireless terminal and a second transmission mode for communicating with the wireless terminal, the determining comprising:
(1) if the node is configured to use the first transmission mode and the terminal speed value exceeds a terminal speed threshold, then determining not to switch from the first transmission mode to the second transmission mode;(2) if the node is configured to use the first transmission mode and the terminal speed value does not exceed the terminal speed threshold, then:
(2a) obtaining a first mode throughput value;(2b) determining to switch to the second transmission mode when the first mode throughput value exceeds a throughput threshold; and(2c) determining not to switch from the first transmission mode to the second transmission mode when the first mode throughput value does not exceed the throughput threshold;(3) if the node is configured to use the second transmission mode and the terminal speed value exceeds the terminal speed threshold, then determining to switch from the second transmission mode to the first transmission mode; and(4) if the node is configured to use the second transmission mode and the terminal speed value does not exceed the terminal speed threshold, then:
(4a) obtaining a second mode throughput value;(4b) determining to switch to the first transmission mode when the second mode throughput value does not exceed the throughput threshold; and(4c) determining not to switch from the second transmission mode to the first transmission mode when the second mode throughput value does exceed the throughput threshold.