# US 2017/0288307 A1 · Beamforming method, apparatus for polarized antenna array and radio communication device and system thereof > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2017/0288307 A1 - Document ID: US20170288307A1 - Status: Published application - Kind: A1 - Application number: 15/626,973 - Filed: 2017-06-19 - Published: 2017-10-05 - Earliest claimed: 2013-06-06 - Assignees: Telefonaktiebolaget LM Ericsson (publ) - Applicants: Telefonaktiebolaget Lm Ericsson (Publ) - Inventors: Yang HU; David ASTELY; Zhiheng GUO; Muhammad lmadur RAHMAN; Hai WANG; Ruiqi ZHANG - Web page: https://patentgrep.com/patent/US20170288307A1 ## CPC - H01Q 3/40: with phasing matrix - H04B 7/0408: using two or more beams, i.e. beam diversity - H04B 7/0413: MIMO systems - H04B 7/0469: {taking special antenna structures, e.g. cross polarized antennas into account} - H04B 7/0617: {for beam forming} - H04B 7/0686: {Hybrid systems, i.e. switching and simultaneous transmission} - H04B 7/0691: {using subgroups of transmit antennas} - H04B 7/10: Polarisation diversity; Directional diversity - H04B 7/0671: {using different delays between antennas} - H01Q: ANTENNAS, i.e. RADIO AERIALS (radiators or antennas for microwave heating H05B6/72) - H04B: TRANSMISSION ## Abstract The invention discloses a beamforming method for polarized antenna array consisting of a plurality of antenna elements, applied to single layer beamforming or dual layer beamforming, which includes the steps: determining (201) first beamforming weights for phase compensation among the antenna elements within each polarization direction; determining (202) second beamforming weights for phase compensation between equivalent channels of two polarization directions; and calculating (203) hybrid beamforming weights as product of the first beamforming weights and the second beamforming weights. A beamforming apparatus for polarized antenna array is also provided in the invention as well as a radio communication device and a system thereof With the invention, the single-layer and dual-layer beamforming weights are determined for the cross-polarized antenna array without requiring full channel knowledge or the aid of PMI. Computation complexity is lowered and full power amplifier utilization can be achieved. ## Claims ### Claim 1 A beamfouning method for a polarized antenna array comprising a plurality of antenna elements, the method comprising: determining, by a radio communication device, weights for each of a first and second polarization direction of said antenna array; determining, by the radio communication device, a phase compensation across said first and second polarization directions of said antenna array; and calculating, by the radio communication device, hybrid beamforming weights based on said weights for each of said first and second polarization directions and said phase compensation across said first and second polarization directions. ### Claim 2 (depends on 1) The method of claim 1, further comprising: transmitting, by the radio communication device, to a terminal, one or more signals weighted with said hybrid beamforming weights. ### Claim 3 (depends on 1) The method of claim 1, wherein said weights for each of said first and second polarization directions are determined jointly. ### Claim 4 (depends on 1) The method of claim 1, wherein said determining weights for each of said first and second polarization directions further comprises: determining a first correlation vector for said first polarization direction; and determining a second correlation vector for said second polarization direction. ### Claim 5 (depends on 4) The method of claim 4, wherein said deteiiiiining weights for each of said first and second polarization directions further comprises: filtering at least one of said first and second correlation vectors. ### Claim 6 (depends on 5) The method of claim 5, wherein said filtering is performed using a forgetting factor based on one or more uplink channel coefficients. ### Claim 7 (depends on 1) The method of claim 1, wherein determining a phase compensation across said first and second polarization directions further comprises: determining an equivalent channel for said first polarization direction; and deteimining an equivalent channel for said second polarization direction. ### Claim 8 (depends on 7) The method of claim 7, wherein determining a phase compensation across said first and second polarizations direction further comprises: determining a correlation vector of the first and second polarized directions based on said equivalent channels. ### Claim 9 (depends on 8) The method of claim 8, wherein said determining a phase compensation across said first and second polarizations direction further comprises: filtering said correlation vector of the first and second polarized directions using a forgetting factor based on one or more uplink channel coefficients. ### Claim 10 (depends on 1) The method of claim 1, wherein said phase compensation across said first and second polarization directions is for a single sub-band. ### Claim 11 (depends on 1) The method of claim 1, wherein said hybrid beamforming weights are determined as a product of said weights for each of said first and second polarization directions and weights for said phase compensation across said first and second polarization directions. ### Claim 12 (depends on 2) The method of claim 2, wherein said signals are transmitted on a sub-band m using compensation defined according to: p 1 m = e - j · 2  π · m  τ N where τ is the artificial delay in samples for a size-N FFT. ### Claim 13 (depends on 1) The method of claim 1, wherein said radio communication device employs dual-layer beamforming with first and second layers, and wherein weights within a polarization direction are equal in the first and second layer and phase compensation between polarizations is orthogonal between said first and second layer. ### Claim 14 A radio communication device, comprising: an antenna array; and a transmitter configured to transmit a plurality of signals to a terminal using said antenna array, wherein said signals are weighted with one or more hybrid beamforming weights, wherein at least one of said hybrid beamforming weights is based on a first beamforming weight for phase compensation among antenna elements within a polarization direction of said antenna array and a second beamforming weight for phase compensation between equivalent channels of two polarization directions of said antenna array. ### Claim 15 (depends on 14) The radio communication device according to claim 14, wherein said first beam forming weight is calculated using a correlation vector for a polarization direction of said antenna array. ### Claim 16 (depends on 15) The radio communication device according to claim 15, wherein said device provides dual layer beamforming, and the first beamforming weights within each polarization direction for a second layer are the same as for a first layer. ### Claim 17 (depends on 16) The radio communication device according to claim 16, wherein, for the compensation phase between the two polarization directions, a π phase difference is introduced between the two layers to allow overall beamforming weights of the two layers to be orthogonal to each other. ### Claim 18 (depends on 17) The beamforming apparatus according to claim 17, wherein a coefficient of 1/√{square root over (2)} is multiplied with the hybrid beamforming weights to split power equally between two layers on each antenna element of said array. ### Claim 19 A method for transmitting signals from a radio communication device having a polarized antenna array, the method comprising: determining one or more first beamforming weights for phase compensation among a plurality of antenna elements of said antenna array within at least one polarization direction; determining one or more second beamfoiuiing weights for phase compensation between equivalent channels of two polarization directions; calculating one or more hybrid beamforming weights based on said first beamforming weights and said second beamforming weights; and transmitting, from said radio communication device to a terminal, one or more signals weighted with said hybrid beamfoiniing weights. ### Claim 20 (depends on 19) The method according to claim 19, wherein the step of determining first beamforming weights further comprises correlation vector calculation for each polarization direction.