US 8,818,440 B2Granted

Apparatus and method for controlling power in distributed multiple input multiple output wireless communication system

AssigneesSamsung Electronics Co., Ltd., Industry-University Cooperation Foundation Sogang University

InventorsJae-Yun Ko, Keun-Chul Hwang, Seung-Won Kang, Soon-Young Yoon, Won-Jin Sung, Byung-Seok Lee, Ji-Won Lee

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Abstract

An apparatus is operable to control power of a base station in a distributed Multiple Input Multiple Output (MIMO) wireless communication system. At least one beamforming matrix is used for processing transmission signals to terminals included in a terminal set for a multiple access is determined. Minimum power values required for satisfying a minimum transmission rate of the terminals are determined. Whether optimum power values exist is determined using the minimum power values, the beamforming matrix, and a limit transmission power of the base station. When the optimum power values exist, transmission power values for respective terminals are determined in a range meeting the limit transmission power of the base station.

Claims24

Dependent claims

A method for controlling power of a base station participating in cooperative transmission in a Multiple Input Multiple Output (MIMO) wireless communication system, the method comprising:

determining at least one beamforming matrix for processing transmission signals to terminals included in a terminal set for a multiple access by a plurality of base stations participating in cooperative transmission;
determining minimum transmission power values for a minimum transmission rate of the terminals;
determining total transmission power values for each of the base stations for a case of using the minimum transmission power according to a power gain by the beamforming matrix;
determining whether each of the total transmission power values exceeds each of limit transmission powers of the plurality of the base stations;
if the total transmission power values do not exceed all of the limit transmission powers, determining transmission power values for respective terminals in a range meeting the limit transmission power of the base stations;
and
if at least one of the total transmission power values exceed the limit transmission powers, removing one of:
a terminal having a largest minimum power value, a terminal having a largest power gain through beamforming, and a terminal having a largest power that each base station allocates in order to satisfy a minimum transmission rate, from the terminal set,
wherein the determining of the transmission power values comprises:
determining a temporary power value of the terminal using a Lagrangian multiplier for a constraint condition for the limit transmission power, the beamforming matrix, and noise power experienced by a terminal;
and
determining a larger one of the temporary power value and a minimum power value of the terminal as a power value of the terminal.

9 more elements

An apparatus of a base station that participates in cooperative transmission in a Multiple Input Multiple Output (MIMO) wireless communication system, the apparatus comprising:

a calculator configured to determine at least one beamforming matrix for processing transmission signals to terminals included in a terminal set for a multiple access by a plurality of base stations participating in cooperative transmission;
and
an allocator configured to:
determine minimum transmission power values required for satisfying a minimum transmission rate of the terminals;
determine total transmission power values for each of the base stations for a case of using the minimum transmission power with consideration of a power gain by the beamforming matrix;
determine whether each of the total transmission power values exceeds each of limit transmission powers of the plurality of the base stations;
if the total transmission power values do not exceed all of the limit transmission powers, determine transmission power values for respective terminals in a range meeting the limit transmission power of the base stations;
and
if at least one of the total transmission power values exceeds the limit transmission powers remove one of a terminal having a largest minimum power value, a terminal having a largest power gain through beamforming, and a terminal having a largest power to be allocated by each base station in order to satisfy a minimum transmission rate, from the terminal set,
wherein the allocator is further configured to, to determine the transmission power values, determine a temporary power value of the terminal using a Lagrangian multiplier for a constraint condition for the limit transmission power, the beamforming matrix, and noise power experienced by a terminal, and, determines a larger one of the temporary power value and a minimum power value of the terminal as a power value of the terminal.

7 more elements

Dependencies are inferred from the claim text.