Patent ID: 11963111
Assignee: NOKIA SOLUTIONS AND NETWORKS OY
Field: Telecommunications (Electrical engineering)
Classification: CPC H | IPC H

Claim 15:
16. The apparatus of claim 1, wherein the communication system is an orthogonal frequency division multiplexing system with a set of subcarriers S, one or more of a plurality of access point antennas of the one or more access points have different power constraints, and the set of power allocation weights is an M dimensional vector w=(w1, . . . , wM)T∈+M, where M is the number of access point antennas of the one or more access points, the downlink received channel estimates for the subcarrier l∈S between the M access point antennas and a number of K user equipment antennas of one or more user equipments is represented with G(l)∈M×K, and wherein the instructions, when executed with the at least one processor, cause the apparatus to perform iteratively updating the set of power allocation weights, w, comprising with:
initializing the set of power allocation weights, w, to an initial set of power allocation weights, w0∈+M;
for the one or more iterations, 1≤n≤N, where N is a maximum number of iterations, updating the n-th set of power allocation weights, wn, with computing wn=ΩS (wn−1), where:, Ω
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and
where the (n-1)-th set of power allocation weights are denoted wn−1=(w1[n−1], . . . , wM[n−1])T∈+M×1, wM[n−1]∈+ the m-th weight of the (n-1)-th set of power allocation weights, wn−1, Pm2 is the power constraint on the m-th transmit chain, and, r
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 is the square root of the total transmit power for access point antenna m incorporating contributions for all subcarriers l∈S, where qm(l)(wn−1) is the mth row of the precoder matrix for subcarrier l∈S,Q(l)(w); and
outputting for the subcarriers in the set of subcarriers data representative of a precoder matrix based on Q(l)(wn) or Q(l)(wn−1) for l∈S.