Patent ID: 8031686

Claim:
A method of controlling transmission power of signal transmitters and modulation and coding of transmitted signals in a multi-cell wireless communication system for increasing service capacity of a cell and decreasing inter-cell interference with nearby cells, the method comprising: arranging a communication channel into multiple subchannels, wherein each subchannel consists of at least one subcarrier; and adaptively controlling the modulation and coding of transmitted signals and signal transmission power, wherein the adaptive control is based on rules and constraints derived from system parameters and performance measurements, and wherein a selected transmission power level satisfies a Rise over Thermal (RoT) threshold requirement, and wherein the adaptive control comprises: a first process wherein an achievable Channel Quality Information (Q new ) at the receiver is updated by: Q new =Q current +P max −P current , where Q current denotes a recent measured CQI (Channel Quality Information) at a receiver, P max denotes a maximum transmission power available at a transmitter, and P current denotes a recent transmission power at the transmitter; in a case where a primary criteria is to maximize throughput while controlling transmission power: if Q new exceeds CQI requirement for a highest MCS (modulation and coding scheme) in a protocol, the highest MCS is selected and P new is set as the transmission power level for that MCS with a certain margin; if Q new is lower than the CQI requirement for the highest MCS, the maximum transmission power (P new ) is selected to derive a corresponding MCS based on the value of Q new ; and if Q new is lower than the CQI requirement for the lowest MCS in the protocol, transmission may be denied and outage process may start; in a case where the primary criteria is to minimize transmission power while meeting a data rate requirement: if Q new exceeds the CQI requirement for a given MCS in the protocol, a necessary transmission power level is set for the given MCS with a certain margin; and if Q new is lower than the CQI requirement for the given or lowest MCS, transmission is denied; and a second process wherein an RoT check is performed and, if needed, the power is adjusted to meet the RoT threshold, the second process comprising: R new =R current +P new −P current , where R new denotes a new RoT resulting from the first process computations, and R current denotes an RoT measurement before application of P new , and wherein: if R new is less than the RoT threshold, decisions made during the first process concerning the transmission power level and MCS are maintained; and if R new exceeds the RoT threshold, the transmission power level is reduced to meet the RoT threshold requirement; and a new transmission power level is calculated as: P new =P current +R threshold −R current , and a new achievable CQI is calculated as: Q new =Q current +R threshold −R current , where R threshold denotes the RoT threshold and an appropriate MCS is selected based on Q new .