| 摘要 |
According to an aspect of the present invention, the power efficiency of a precoded OFDM signal is improved by a method in a network node, e.g. a mobile terminal, for adapting a signal for multi-antenna transmission. In a first step, the network node receives at least a first parameter being related to the transmit power requirements of the network node. The network node then receives, a second parameter indicating a precoder W. In a further step, the network node determines a modified precoder {tilde over (W)}, having the same dimensions as W, using the precoder W and the at least first parameter; then, the network node adapts, the signal for multi-antenna transmission using the modified precoder {tilde over (W)}. |
| 主权项 |
1. A method in a network node for adapting an OFDM or SC-OFDM signal for multi-antenna transmission, the network node being comprised in a wireless communications network, the method comprising the following steps:
receiving at least a first parameter being related to the transmit power requirements of the network node; receiving a second parameter indicating a spatial precoder W; determining, based on the at least first parameter, whether to use a modified spatial precoder; and, if it is determined to use a modified spatial precoder, determining a spatial precoder {tilde over (W)}, having the same dimensions as W, using the spatial precoder W and the at least first parameter, wherein each element {tilde over (w)}i,j in {tilde over (W)} equals the corresponding element wi,j in W multiplied by a factor si,j, wherein the factor si,j depends on the value of the at least first parameter, and wherein the factor si,j is less than or equal to one, and greater than or equal to zero; adapting said signal for multi-antenna transmission using the spatial precoder {tilde over (W)};wherein the step of determining a spatial precoder {tilde over (W)} comprises the steps of:
determining a shaping matrix S, having the same dimensions as W,
such that each element si,j of S has a value either equal to one, or equal to one multiplied by a factor α, wherein the factor α depends on the value of the at least first parameter, and wherein the value of α is less than or equal to one, and greater than or equal to zero; and determining the spatial precoder {tilde over (W)} as the element-wise product of S and W.
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