Method and node in a wireless communication network

1. A method, in a radio network node, for wireless communication with a user equipment, wherein the radio network node comprises a plurality of antenna elements, forming a multiple antenna array which is configured for massive Multiple Input Multiple Output (MIMO) transmission, the method comprising:

splitting and phase shifting a signal to be transmitted to the user equipment to obtain multiple beamformed signals, wherein the multiple beamformed signals are transmitted by the multiple antenna array;

detecting a peak power of a signal received by the multiple antenna array that exceeds a threshold value;

manipulating the signal received by the multiple antenna array until the peak power of the signal received by the multiple antenna array is lower than the threshold value, wherein the manipulation includes spatial and temporal shaping of a correction signal (z) applied to the signal to be transmitted until the peak power is lower than the threshold value and the spatial and temporal shaping of the correction signal (z) comprises determining an angle of departure (ϕ 1 , ϕ 2 , . . . , ϕn) of each of the beamformed signals;

removing energy of the correction signal (z) in directions according to the determined angle of departure of each of the beamformed signals; and

transmitting the manipulated signal to the user equipment by way of the multiple beamformed signals transmitted by the multiple antenna array.

2. The method according to claim 1 , where the spatial and temporal shaping of the correction signal (z) comprises:

transformation of the correction signal (z) into antenna domain and application of a filter for filtering the correction signal (z).

3. The method according to claim 1 , wherein the signal to be transmitted comprises Orthogonal Frequency Division Multiplexing (OFDM) symbols.

4. A radio network node configured for wireless communication with a user equipment, the radio network node comprising:

a plurality of antenna elements forming a multiple antenna array configured for massive Multiple Input Multiple Output (MIMO) transmission;

a processor configured to:

split and phase shift a signal to be transmitted to the user equipment to obtain multiple beamformed signals, wherein the multiple beamformed signals are transmitted by the multiple antenna array,

detect a peak power of a signal received by the multiple antenna array that exceeds a threshold value,

manipulate the signal received by the multiple antenna array until the peak power of the signal received by the multiple antenna array is lower than the threshold value, wherein the manipulating includes spatial and temporal shaping of a correction signal (z) applied to the signal to be transmitted,

determine an angle of departure (ϕ 1 , ϕ 2 , . . . , ϕn) of each of the beamformed signals, and

remove energy of the correction signal (z) in directions according to the determined angle of departure of each of the beamformed signals; and

a transmitter configured to transmit the manipulated signal to the user equipment by way of the multiple beamformed signals transmitted by the multiple antenna array.

5. The radio network node according to claim 4 , wherein the processor is further configured to:

further phase shift one of the multiple beamformed signals until the peak power of the signal received by the multiple antenna array is lower than said threshold value;

estimate power loss and phase error on the further phase shifted signal, as perceived by the user equipment; and

compensate the further phase shifted signal based on the estimated power loss and phase error.

6. The radio network node according to claim 5 , wherein the processor is further configured to manipulate the signal by spatial and temporal shaping of a correction signal (z), where correction signal (z) is applied to the signal to be transmitted to the user equipment, until the peak of power of the signal received by the multiple antenna array is lower than said threshold value.

7. The radio network node according to claim 6 , wherein the processor is further configured to transform the correction signal (z) into antenna domain and to apply a filter for filtering the correction signal (z).

8. The radio network node according claim 4 , wherein the radio network node comprises an evolved NodeB (eNodeB); and wherein the wireless communication network is based on 3rd Generation Partnership Project Long Term Evolution (3GPP LTE).

9. A computer program product comprising a non-transitory computer readable storage medium storing program code thereon for use by a radio network node, for wireless communication with a user equipment, wherein the program code comprises instructions for executing a method comprising:

splitting and phase shifting a signal to be transmitted to the user equipment to obtain multiple beamformed signals;

detecting a peak power of one beamformed signal in the multiple beamformed signals that exceeds a threshold value;

manipulating the one beamformed signal until the peak power of the one beamformed signal is lower than said the threshold value, wherein the manipulation includes shaping of a correction signal (z), where the shaping comprises determining an angle of departure of at least the one beamformed signal;

removing energy of the correction signal (z) in a direction according to the determined angle of departure of at least the one beamformed signal; and

transmitting said the manipulated beamformed signal to the user equipment.

10. The computer program product according to claim 9 , wherein the program code further comprises instructions for executing the method comprising:

the spatial and temporal shaping of the correction signal (z) comprises transformation of the correction signal (z) into an antenna domain and application of a filter for filtering the correction signal (z).