Wireless communication system node with fixed beams having common envelope

This application is a continuation of U.S. application Ser. No. 16/608,244, filed 25 Oct. 2019, which was the National Stage of International Application No. PCT/EP2017/063099, filed 31 May 2017, the disclosures of both of which are incorporated herein by reference in their entirety.

The present disclosure relates to a wireless communication system node that comprises at least two antenna ports. The node further comprises a beamforming controller and a beamforming network which in turn comprises at least two beam ports that are adapted to provide corresponding beams.

Nodes that make use of fixed beamforming is of interest for wireless communication networks, such as Radio Access Networks. Fixed beamforming implies that the spatial coverage area is covered by a fixed number of beams that are static during a certain time, such as during a certain operation. One example for utilizing a fixed beam system is if the base band resources are limited, and a dynamic beam system is not possible. Another example is in a random access scenario where a limited number of beams with relatively high gain, at least higher than one element, is needed to find the UE.

It is therefore a desire to provide a node for a wireless communication system, where the node is arranged for fixed beamforming in a more efficient manner than previously.

It is an object of the present disclosure to provide a node in a wireless communication system, where the node has an antenna arrangement that enables changing of the sector shape, for example the sector width, in wireless cellular networks where all beams are matched to the new sector width.

Said object is obtained by means of a wireless communication system node that comprises at least two antenna ports. The node further comprises a beamforming controller and a beamforming network which in turn comprises at least two beam ports that are adapted to provide corresponding beams. The beamforming controller is arranged to control the beamforming network such that the beams have a common envelope in a desired plane, where the common envelope is adapted to a desired coverage for a certain communication system sector.

Said object is also obtained by means of a method for adapting beam coverage to a desired coverage for a certain communication system sector. The method comprises generating at least two controllable beams and controlling the beams to have a common envelope in a desired plane, where the common envelope is adapted to the desired coverage.

This provides an advantage by enabling distribution of beams in an efficient manner such that the gain is balanced in different directions, and can be adapted to the cell shape.

According to some aspects, the common envelope is adapted to follow a predefined reference curve in an optimal manner.

This provides an advantage by providing a clearly defined aim for the common envelope.

According to some aspects, the beamforming controller is arranged to control the beamforming network to form a plurality of sets of beams such that a plurality of common envelopes is obtained. For each common envelope, the beamforming controller is arranged to determine an angular value where a difference between an amplitude of the common envelope and an amplitude of the reference curve has a lowest value, and where the beamforming controller is arranged to control the beamforming network such that said lowest value is maximized for the next envelope.

This provides an advantage by providing means for practically obtaining the common envelope.

According to some aspects, the node comprises at least two antenna ports that are adapted to be connected to a first polarization, and at least two antenna ports adapted to be connected to a second polarization that is mutually orthogonal to the first polarization.

According to some aspects, the beam ports are adapted to provide corresponding beams of a first beam polarization and corresponding beams of a second beam polarization, orthogonal to the first beam polarization.

According to some aspects, beams of different beam polarizations are at least partly overlaying each other pair-wise, constituting beam pairs with mutually orthogonal polarizations.

This provides an advantage by enabling dual polarized beamforming.

According to some aspects, each beam pair is adapted to cover a corresponding sub-sector comprised in the communication system sector, where at least two sub-sectors have different corresponding angular sizes.

This provides an advantage by enabling dual polarized beamforming that is adapted to the cell shape.

According to some aspects, the node comprises at least one antenna arrangement, where each antenna arrangement in turn comprises at least two antenna devices positioned in a row. Each antenna device comprises a corresponding pair of antenna ports with a corresponding first antenna port and second antenna port. Each antenna device comprises at least one corresponding dual polarized antenna element arranged for transmitting and receiving signals at the first polarization via the corresponding first antenna port and for transmitting and receiving signals at the second polarization via the corresponding second antenna port.

The present disclosure will now be described more in detail with reference to the appended drawings, where:

FIG. 1 shows a schematical view of a wireless communication system node.

FIG. 2 shows a schematical view of an antenna arrangement according to an example of the present disclosure.

FIG. 3 shows a schematical view of beams according to an example of the present disclosure.

FIG. 4 shows a communication system cell.

FIG. 5 shows a flowchart of a method according to the present disclosure.

FIG. 6 shows a wireless communication system node according to some aspects of the present disclosure.

With reference to FIG. 1 , there is a node 1 in a wireless system 43 , where the node 1 comprises three antenna arrangements 21 , 22 , 23 . In the following a first antenna arrangement 21 will be described, but the features of the first antenna arrangement 21 is according to some aspects present also for the other antenna arrangements 22 , 23 . As illustrated in FIG. 2 , the first antenna arrangement 21 comprises four antenna devices 24 , 25 , 26 , 27 positioned in a row. Each antenna device 24 , 25 , 26 , 27 comprises a corresponding pair of antenna ports A, B, C, D with a corresponding first polarization antenna port P 1 A, P 1 B, P 1 C, RID and second polarization antenna port P 2 A, P 2 B, P 20 , P 2 D.

Each antenna device 24 , 25 , 26 , 27 comprises a corresponding dual polarized antenna element 28 , 29 , 30 , 31 arranged for transmitting and receiving signals at a first polarization P 1 via the corresponding first polarization antenna port P 1 A, P 1 B, P 1 C, P 1 D and for transmitting and receiving signals at a second polarization P 2 that is mutually orthogonal to the first polarization P 1 , via the corresponding second antenna port P 2 A, P 2 B, P 2 C, P 2 D.

More in detail, the node 1 comprises a first polarization first antenna port P 1 A, a first polarization second antenna port P 1 B, a first polarization third antenna port P 1 C and a first polarization fourth antenna port P 1 D, where these antenna ports P 1 A, P 1 B, P 1 C, P 1 D are adapted to be connected to the first polarization P 1 . The node further comprises a second polarization first antenna port P 2 A, a second polarization second antenna port P 2 B, a second polarization third antenna port P 2 C and a second polarization fourth antenna port P 2 D, where these antenna ports P 2 A, P 2 B, P 2 C, P 2 D are adapted to be connected to the second polarization P 2 .

The node 1 further comprises a beamforming controller 2 and a beamforming network 3 which in turn comprises a first beam port 4 , second beam port 5 , a third beam port 6 and a fourth beam port 7 , where these beam ports 4 , 5 , 6 , 7 are adapted to provide corresponding beams 12 , 13 , 14 , 15 of a first beam polarization B 1 . The beamforming network 3 furthermore comprises a fifth beam port P 2 A, a sixth beam port P 2 B, a seventh beam port P 2 C and an eighth P 2 D beam port, where these beam ports are adapted to provide corresponding beams 16 , 17 , 18 , 19 of a second beam polarization B 2 , orthogonal to the first beam polarization B 1 .

Beams 12 , 13 , 14 , 15 ; 16 , 17 , 18 , 19 of different beam polarizations B 1 , B 2 are overlaying each other pair-wise, constituting beam pairs 12 , 16 ; 13 , 17 ; 14 , 18 ; 15 ; 19 with mutually orthogonal polarizations. The beams 12 , 13 , 14 , 15 ; 16 , 17 , 18 , 19 have a common envelope 20 in an azimuth plane.

According to the present disclosure, the beamforming controller 2 is arranged to control the beamforming network 3 such that the common envelope 20 is adapted to a desired coverage for a certain communication system sector 37 having a certain angular sector size φ in azimuth. The common envelope 20 is in this example adapted to follow a predefined reference curve 32 in an optimal manner.

More in detail, there is a first beam pair 12 , 16 adapted to cover a first sub-sector 33 , a second beam pair 13 , 17 adapted to cover a second sub-sector 34 , a third beam pair 14 , 18 adapted to cover a third sub-sector 35 and a fourth beam pair 15 , 19 adapted to cover a fourth sub-sector 36 . The first sub-sector 33 has a first angular size φ 1 in azimuth, the second sub-sector 34 has a second angular size φ 2 in azimuth, the third sub-sector 35 has a third angular size φ 3 in azimuth, and the fourth sub-sector 36 has a fourth angular size φ 4 in azimuth. The first angular size φ 1 equals the fourth angular size φ 4 , and the second angular size φ 2 equals the third angular size φ 3 . The first angular size φ 1 exceeds the second angular size φ 2 , and correspondingly the fourth angular size φ 4 exceeds the third angular size φ 3 . Generally, at least two sub-sectors 33 , 34 ; 35 , 36 have different corresponding angular sizes φ 1 , φ 2 ; φ 3 , φ 4 .

This means that, non-uniform fixed beams are obtained. This is advantageous, since uniform beams can result in several problems. For example, uniform beams are typically the smallest beam an antenna aperture can generate which implies that many beams are needed to cover a desired area. Also, the gain of fixed beams in the maximum direction can be too high compared to boresight direction, which can generate interference.

With reference to FIG. 4 , the communication system sector 37 is according to some aspects comprised in a hexagon-shaped communication system cell 42 having a certain cell shape. There is an evident range difference between boresight direction 44 and at a maximum azimuth direction 45 , and a Gaussian beam with 65 beamwidth is a possible solution.

The present disclosure discloses using an optimized number of non-uniform beams to cover a specific area while optimizing interference. The beams are distributed such that the gain is balanced in different directions in accordance with the cell shape.

With reference to FIG. 3 and FIG. 5 , the present disclosure relates to a method for adapting beam coverage to a desired coverage for a certain communication system sector 37 . The method comprises:

38 : Generating at least two controllable beams 12 , 13 , 14 , 15 .

39 : Controlling the beams 12 , 13 , 14 , 15 to have a common envelope 20 in a desired plane, where the common envelope 20 is adapted to said desired coverage.

According to some aspects, the common envelope 20 is adapted to follow a predefined reference curve 32 in an optimal manner.

In that case, according to some further aspects, the method comprises:

40 : Forming a plurality of sets of beams 12 , 13 , 14 , 15 such that a plurality of common envelopes is obtained.

For each common envelope 20 , the method further comprises:

41 : Determining an angular value where a difference between an amplitude of the common envelope 20 and an amplitude of the reference curve 32 has a lowest value.

42 : Maximizing said lowest value for the next envelope.

With reference to FIG. 1 , FIG. 3 and FIG. 6 , there is a wireless communication system node 1 that comprises:

A generating module X 38 that is that is configured to generate at least two controllable beams 12 , 13 , 14 , 15 .

A controlling module X 39 that is that is configured to control the beams 12 , 13 , 14 , 15 to have a common envelope 20 in a desired plane, where the common envelope 20 is adapted to said desired coverage.

According to some aspects, the common envelope 20 is adapted to follow a predefined reference curve 32 in an optimal manner.

In that case, according to some further aspects, the wireless communication system node 1 comprises a forming module X 40 that is configured to form a plurality of sets of beams 12 , 13 , 14 , 15 such that a plurality of common envelopes is obtained. For each common envelope 20 , the wireless communication system node 1 comprises:

A determining module X 41 that is configured to determine an angular value where a difference between an amplitude of the common envelope 20 and an amplitude of the reference curve 32 has a lowest value.

A maximizing module X 42 that is configured to maximize said lowest value for the next envelope.

The present disclosure is not limited to the examples above, but may vary freely within the scope of the appended claims. For example, the node 1 may comprise one or more antenna arrangements, each antenna arrangement being arranged to cover a certain communication system sector 37 . The communication system sector or sectors do not have to lie in an azimuth plane, by may lie in any suitable plane, such as for example an elevation plane, and is generally referred to as a desired plane. The communication system sector 37 , comprises at least two sub-sectors.

The antenna devices 24 , 25 , 26 , 27 are positioned in a row one after the other, where the row may lie in any suitable plane such as a horizontal plane or a vertical plane.

According to some aspects, each antenna device 24 , 25 , 26 , 27 comprises on or more antenna elements which are placed such that they form a one-dimensional array antenna or a two-dimensional array antenna. According to some further aspects, each antenna element is in turn constituted by several sub-elements or even sub-arrays.

Beams of different beam polarizations are according to some aspects at least partly overlaying each other pair-wise.

The antenna devices have been described as dual polarized, and there have been described beams that are dual polarized. According to some aspects, the antenna devices are single polarized, and the beams then only have only one polarization. Then no pair-wise overlaying beam pairs are formed, but then single beams are all angularly spread out similar to the way the beam pairs are spread out. Then there is only one beam for each sub-sector.

Generally, the node 1 comprises at least two antenna ports P 1 A, P 1 B, P 1 C, P 1 D; P 2 A, P 2 B, P 2 C, P 2 D and at least two beam ports 4 , 5 , 6 , 7 ; 8 , 9 , 10 ; 11 , enabling at least two beams 12 , 13 , 14 , 15 . The communication system sector 37 thus comprises at least two sub-sectors 33 , 34 , 35 , 36 .

When there is a first beam polarization B 1 and a second beam polarization B 2 , these beam polarizations B 1 , B 2 can change for different angles in the desired plane, but are maintained mutually orthogonal.

The beamforming network 3 is according to aspects digital; alternatively analogue where, for example, the beams are time multiplexed.

The term beam refers to a beamformed antenna beam.

As mentioned initially, fixed beamforming, that is used for obtaining fixed beams, implies that a spatial coverage area is covered by a fixed number of beams that are static during a certain time, such as during a certain operation.

Term such as for example equal and orthogonal do in this context not mean to interpreted as mathematically exact, but within what is practically obtainable in this field of technology.

Generally, the present disclosure relates to a wireless communication system node 1 , where the node 1 comprises at least two antenna ports P 1 A, P 1 B, P 1 C, P 1 D; P 2 A, P 2 B, P 2 C, P 2 D, where the node 1 further comprises a beamforming controller 2 and a beamforming network 3 which in turn comprises at least two beam ports 4 , 5 , 6 , 7 ; 8 , 9 , 10 , 11 that are adapted to provide corresponding beams 12 , 13 , 14 , 15 ; 16 , 17 , 18 , 19 . he beamforming controller 2 is arranged to control the beamforming network 3 such that the beams 12 , 13 , 14 , 15 ; 16 , 17 , 18 , 19 have a common envelope 20 in a desired plane, where the common envelope 20 is adapted to a desired coverage for a certain communication system sector 37 .

According to some aspects, the common envelope 20 is adapted to follow a predefined reference curve 32 in an optimal manner.

According to some aspects, the beamforming controller 2 is arranged to control the beamforming network 3 to form a plurality of sets of beams 12 , 13 , 14 , 15 ; 16 , 17 , 18 , 19 such that a plurality of common envelopes is obtained, where, for each common envelope 20 , the beamforming controller 2 is arranged to determine an angular value where a difference between an amplitude of the common envelope 20 and an amplitude of the reference curve 32 has a lowest value, and where the beamforming controller 2 is arranged to control the beamforming network 3 such that said lowest value is maximized for the next envelope.

According to some aspects, the node 1 comprises at least two antenna ports P 1 A, P 1 B, P 1 C, P 1 D that are adapted to be connected to a first polarization P 1 , and at least two antenna ports P 2 A, P 2 B, P 2 C, P 2 D adapted to be connected to a second polarization P 2 that is mutually orthogonal to the first polarization P 1

According to some aspects, said beam ports 4 , 5 , 6 , 7 ; 8 , 9 , 10 ; 11 are adapted to provide corresponding beams 12 , 13 , 14 , 15 of a first beam polarization B 1 and corresponding beams 16 , 17 , 18 , 19 of a second beam polarization B 2 , orthogonal to the first beam polarization B 1 .

According to some aspects, beams 12 , 13 , 14 , 15 ; 16 , 17 , 18 , 19 of different beam polarizations B 1 , B 2 are at least partly overlaying each other pair-wise, constituting beam pairs 12 , 16 ; 13 , 17 ; 14 , 18 ; 15 ; 19 with mutually orthogonal polarizations.

According to some aspects, each beam pair 12 , 16 ; 13 , 17 ; 14 , 18 ; 15 , 19 is adapted to cover a corresponding sub-sector 33 , 34 , 35 , 36 comprised in the communication system sector 37 , where at least two sub-sectors 33 , 34 ; 35 , 36 have different corresponding angular sizes φ 1 , φ 2 ; φ 3 , φ 4 .

According to some aspects, the node 1 comprises at least one antenna arrangement 21 , 22 , 23 , where each antenna arrangement 21 , 22 , 23 in turn comprises at least two antenna devices 24 , 25 , 26 , 27 positioned in a row, each antenna device 24 , 25 , 26 , 27 comprising a corresponding pair of antenna ports A, B, C, D with a corresponding first antenna port P 1 A, P 1 B, P 1 C, P 1 D and second antenna port P 2 A, P 2 B, P 2 C, P 2 D, where each antenna device 24 , 25 , 26 , 27 comprises at least one corresponding dual polarized antenna element 28 , 29 , 30 , 31 arranged for transmitting and receiving signals at the first polarization P 1 via the corresponding first antenna port P 1 A, P 1 B, P 1 C, P 1 D and for transmitting and receiving signals at the second polarization P 2 via the corresponding second antenna port P 2 A, P 2 B, P 2 C, P 2 D.

The present disclosure also relates to a method for adapting beam coverage to a desired coverage for a certain communication system sector 37 , where the method comprises:

38 : generating at least two controllable beams 12 , 13 , 14 , 15 ; 16 , 17 , 18 , 19 ;

39 : controlling the beams 12 , 13 , 14 , 15 ; 16 , 17 , 18 , 19 to have a common envelope 20 in a desired plane, where the common envelope 20 is adapted to said desired coverage.

According to some aspects, the common envelope 20 is adapted to follow a predefined reference curve 32 in an optimal manner.

According to some aspects, the method comprises:

40 : forming a plurality of sets of beams 12 , 13 , 14 , 15 ; 16 , 17 , 18 , 19 such that a plurality of common envelopes is obtained, where, for each common envelope 20 , the method further comprises:

41 : determining an angular value where a difference between an amplitude of the common envelope 20 and an amplitude of the reference curve 32 has a lowest value, and

42 : maximizing said lowest value for the next envelope.

According to some aspects, the method comprises generating controllable beams 12 , 13 , 14 , 15 having a first beam polarization B 1 , and generating beams 16 , 17 , 18 , 19 having a second beam polarization B 2 , orthogonal to the first beam polarization B 1 .

According to some aspects, beams 12 , 13 , 14 , 15 ; 16 , 17 , 18 , 19 of different beam polarization B 1 , B 2 are at least partly overlaying each other pair-wise, constituting beam pairs 12 , 16 ; 13 , 17 ; 14 , 18 ; 15 ; 19 with mutually orthogonal polarizations.

According to some aspects, each beam pair 12 , 16 ; 13 , 17 ; 14 , 18 ; 15 ; 19 is used for covering a corresponding sub-sector 33 , 34 , 35 , 36 comprised in the communication system sector 37 , where at least two sub-sectors 33 , 34 ; 35 , 36 have different corresponding angular sizes φ 1 , φ 2 ; φ 3 , φ 4 .