Modern wireless communication protocols may use multiple-input and multiple-output (MIMO) transmission schemes when transferring communications to wireless communication devices. MIMO uses multiple antennas for each carrier in a wireless access node in order to improve communication transfer performance. The improvements in communication transfer performance may include increased wireless range and data throughput. Some examples of MIMO wireless protocols include Worldwide Interoperability for Microwave Access (WiMAX), Long Term Evolution (LTE), and the latest 802.11n wireless protocols (Wi-Fi).
A key factor in the proper implementation of a MIMO communication system is scattering, since higher degrees of scattering enable increased de-correlation of the signals at the receiver, which is necessary for MIMO to function properly. Typically, rich scattering in MIMO propagation environments is required for the channel capacity to scale linearly with the number of antennas. The MIMO mode utilized for communications has an impact on the effective cell radius of the base station. Higher order MIMO modes require a reduction in power per symbol when compared to lower order MIMO modes. The reduction in power per symbol required for higher order MIMO modes, such as eight by eight MIMO, requires a reduction in power per symbol which in turn reduces the effective cell radius of the serving base station. The effectively smaller cell radius of higher order MIMO modes can lead to a degraded user experience for those who are not within range of the smaller coverage area provided by these modes.
Overview
A method of operating a wireless access node to facilitate dynamic assignment of multiple-input multiple-output (MIMO) modes is disclosed. The method comprises receiving a scattering coefficient transmitted from a wireless communication device served by the wireless access node. The method further comprises comparing the scattering coefficient to a scattering threshold. The method further comprises, if the scattering coefficient exceeds the scattering threshold, selecting a lower order MIMO mode for the wireless communication device. The method further comprises assigning the lower order MIMO mode to the wireless communication device.
A wireless access node to facilitate dynamic assignment of multiple-input multiple-output (MIMO) modes comprises a wireless communication transceiver and a processing system. The wireless communication transceiver is configured to receive a scattering coefficient transmitted from a wireless communication device served by the wireless access node. The processing system is configured to compare the scattering coefficient to a scattering threshold, and if the scattering coefficient exceeds the scattering threshold, select a lower order MIMO mode for the wireless communication device and assign the lower order MIMO mode to the wireless communication device.
A computer apparatus to facilitate dynamic assignment of multiple-input multiple-output (MIMO) modes comprises software instructions and at least one non-transitory computer-readable storage medium storing the software instructions. The software instructions are configured, when executed by a wireless access node, to direct the wireless access node to receive a scattering coefficient transmitted from a wireless communication device served by the wireless access node. The software instructions are further configured to direct the wireless access node to compare the scattering coefficient to a scattering threshold, and if the scattering coefficient exceeds the scattering threshold, select a lower order MIMO mode for the wireless communication device and assign the lower order MIMO mode to the wireless communication device.