# US 10,455,591 B2 · Apparatuses, methods, computer programs, and computer program products for interference avoidance

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- Number: US 10,455,591 B2
- Document ID: US10455591B2
- Status: Granted
- Kind: B2
- Application number: 15/526,382
- Filed: 2017-04-25
- Published: 2018-10-25
- Granted: 2019-10-22
- Earliest claimed: 2017-04-25
- Assignees: Telefonaktiebolaget LM Ericsson (publ)
- Applicants: Telefonaktiebolaget Lm Ericsson (Publ)
- Inventors: Torbjörn Wigren; Mats Åhlander
- Web page: https://patentgrep.com/patent/US10455591B2

## CPC

- H04W 72/541: using the level of interference
- H04B 7/0417: Feedback systems
- H04B 7/0456: Selection of precoding matrices or codebooks, e.g. using matrices antenna weighting
- H04B 7/0617: {for beam forming}
- H04B 7/0626: {Channel coefficients, e.g. channel state information [CSI]}
- H04B 7/06952: {Selecting one or more beams from a plurality of beams, e.g. beam training, management or sweeping}
- H04W 72/044: based on the type of the allocated resource
- H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72)
- H04B: TRANSMISSION

## Abstract

A scheduling function node (SF) uses the beams available for each WCD to avoid scheduling a transmission that would imply that interference between WCDs is created. In the simplest form such a scheme could be described as follows: (1) avoid scheduling transmission in directions that coincide between WCDs (here, a direction would typically be represented by both azimuth and elevation angles) and (2) when the available beam directions do not allow interference avoidance, accounting for this fact and exploiting other types of orthogonality in the scheduling of time-frequency resources.

## Claims

### Claim 1

A method for interference avoidance, comprising:
a network node obtaining first candidate beam information identifying a first set of one or more candidate beams for a first wireless communication device, WCD, being served by the network node, the first set of candidate beams for the first WCD comprising a first candidate beam having a first direction;
the network node obtaining second candidate beam information identifying a second set of one or more candidate beams for a second WCD being served by the network node, the second set of candidate beams for the second WCD comprising a second candidate beam having a second direction; and
the network node, using the first and second candidate beam information, scheduling i) the transmission of first data to the first WCD and the transmission of second data to the second WCD, wherein
the scheduling of the transmissions comprises: selecting a transmission resource for use in transmitting the first data to the first WCD, selecting a transmission resource for use in transmitting the second data to the second WCD,
selecting the transmission resource for use in transmitting the first data to the first WCD further comprises selecting a candidate beam from the first set of candidate beams for the first WCD, and
selecting the transmission resource for use in transmitting the second data to the second WCD further comprises selecting a candidate beam from the second set of candidate beams for the second WCD,
selecting a candidate beam from the first set of candidate beams for the first WCD comprises selecting a candidate beam from a first subset of candidate beams, wherein each candidate beam included in the first subset of candidate beams is a) included in the first set of candidate beams and b) not included in the second set of candidate beams, and
selecting a candidate beam from the second set of candidate beams for the second WCD comprises selecting a candidate beam from a second subset of candidate beams, wherein each candidate beam included in the second subset of candidate beams is a) included in the second set of candidate beams and b) not included in the first set of candidate beams.

### Claim 2 (depends on 1)

The method of claim 1, wherein
selecting the transmission resource for use in transmitting the first data to the first WCD comprises selecting one or more of: i) a time slot during which the transmission of the first data to the first WCD will occur and ii) a frequency band in which the transmission of the first data to the first WCD will occur, and
selecting the transmission resource for use in transmitting the second data to the second WCD comprises selecting one or more of: i) a time slot during which the transmission of the second data to the second WCD will occur and ii) a frequency band in which the transmission of the second data to the second WCD will occur.

### Claim 3 (depends on 1)

The method of claim 1, wherein, scheduling i) the transmission of first data to the first WCD and ii) the transmission of second data to the second WCD using the first and second candidate beam information comprises:
using the first and second candidate beam information to determine whether it is feasible to select the same time and frequency resources for the transmission of the first data to the first WCD and the transmission of the second data to the second WCD.

### Claim 4 (depends on 3)

The method of claim 3, wherein the step of using the first and second candidate beam information to determine whether it is feasible to select the same time and frequency resources comprises:
determining whether there is at least one beam included in the set of candidate beams for the first WCD that is not included in the set of candidate beams for the second WCD; and
determining whether there is at least one beam included in the set of candidate beams for the second WCD that is not included in the set of candidate beams for first WCD.

### Claim 5 (depends on 4)

The method of claim 4, wherein, as a result of determining that it is feasible to select the same time and frequency resources, the network node selects a time and frequency resource for the transmission of the first data and selects for the second transmission the same time and frequency resources that are selected for the transmission of the second data.

### Claim 6 (depends on 1)

The method of claim 1, wherein
the first beam is defined by a codebook entry identified by a pre-coder matrix index; and
the method further comprises:
the network node using the first beam to transmit a reference signal; and
the network node receiving from the first WCD first channel state information comprising the pre-coder matrix index and first channel quality information.

### Claim 7 (depends on 6)

The method of claim 6, wherein
the network node is a base station having more antenna elements than antenna ports, and
the method further comprises:
the network node using a third beam to transmit the reference signal, wherein the third beam is associated with the pre-coder matrix index,
after transmitting the reference signal using the third beam, the network node receiving from the first WCD second channel state information comprising the pre-coder matrix index and second channel quality information, and
the network node determining whether to add the third beam to the first set of candidate beams based on the second channel quality information received from the first WCD.

### Claim 8 (depends on 7)

The method of claim 7, wherein the method further comprises:
the network node using a fourth beam to transmit the reference signal, wherein the fourth beam is associated with the pre-coder matrix index,
after transmitting the reference signal using the fourth beam, the network node receiving from the first WCD third channel state information comprising the pre-coder matrix index and third channel quality information, and
the network node determining whether to add the fourth beam to the first set of candidate beams based on the third channel quality information received from the first WCD.

### Claim 9 (depends on 8)

The method of claim 8, wherein
the third beam is angularly shifted with respect to the first beam, and
the fourth beam is angularly shifted with respect to the first beam.

### Claim 10 (depends on 1)

The method of claim 1, further comprising:
the network node obtaining the first data for transmission to the first WCD; and
the network node obtaining the second data for transmission to the second WCD.

### Claim 11 (depends on 1)

The method of claim 1, wherein the network node is a base station comprising a scheduling function node, SF.

### Claim 12 (depends on 1)

The method of claim 1, wherein the network node comprises a scheduling function node, SF, and the network node is not a base station.

### Claim 13

A network node for interference avoidance, the network node comprising:
a computer readable medium; and
a data processing apparatus, comprising one or more processors, coupled to the computer readable medium, wherein the data processing apparatus is configured to:
obtain first candidate beam information identifying a first set of one or more candidate beams for a first wireless communication device, WCD, being served by the network node, the first set of candidate beams for the first WCD comprising a first candidate beam having a first direction;
obtain second candidate beam information identifying a second set of one or more candidate beams for a second WCD being served by the network node, the second set of candidate beams for the second WCD comprising a second candidate beam having a second direction; and
schedule i) the transmission of first data to the first WCD and ii) the transmission of second data to the second WCD, wherein
the data processing system is configured to perform the scheduling of the transmissions using the first and second candidate beam information,
the scheduling of the transmissions comprises: selecting a transmission resource for use in transmitting the first data to the first WCD, selecting a transmission resource for use in transmitting the second data to the second WCD, and determining whether the first direction is different than the second direction,
selecting the transmission resource for use in transmitting the first data to the first WCD further comprises selecting a candidate beam from the first set of candidate beams for the first WCD
selecting the transmission resource for use in transmitting the second data to the second WCD further comprises selecting a candidate beam from the second set of candidate beams for the second WCD,
the network node is configured to select a candidate beam from the first set of candidate beams for the first WCD by: 1) determining a first subset of candidate beams for the first WCD, wherein each candidate beam included in the first subset of candidate beams is a) included in the first set of candidate beams and b) not included in the second set of candidate beams; and 2) selecting a candidate beam from the first subset of candidate beams, and
the network node is configured to select a candidate beam from the second set of candidate beams for the second WCD by: 1) determining a second subset of candidate beams for the second WCD, wherein each candidate beam included in the second subset of candidate beams is a) included in the second set of candidate beams and b) not included in the first set of candidate beams; and 2) selecting a candidate beam from the second subset of candidate beams.

### Claim 14 (depends on 13)

The network node of claim 13, wherein, scheduling i) the transmission of first data to the first WCD and ii) the transmission of second data to the second WCD using the first and second candidate beam information comprises:
using the first and second candidate beam information to determine whether it is feasible to select the same time and frequency resources for the transmission of the first data to the first WCD and the transmission of the second data to the second WCD.

### Claim 15 (depends on 14)

The network node of claim 14, wherein the network node is configured to use the first and second candidate beam information to determine whether it is feasible to select the same time and frequency resources by performing a process comprising:
determining whether there is at least one beam included in the set of candidate beams for the first WCD that is not included in the set of candidate beams for the second WCD; and
determining whether there is at least one beam included in the set of candidate beams for the second WCD that is not included in the set of candidate beams for first WCD.

### Claim 16 (depends on 15)

The network node of claim 15, wherein, the network node is configured such that, as a result of determining that it is feasible to select the same time and frequency resources, the network node selects a time and frequency resource for the transmission of the first data and selects for the second transmission the same time and frequency resources that are selected for the transmission of the second data.

### Claim 17 (depends on 13)

The network node of claim 13, wherein
the first beam is defined by a codebook entry identified by a pre-coder matrix index; and
the network node is further configured to:
use the first beam to transmit a reference signal; and
receive from the first WCD first channel state information comprising the pre-coder matrix index and first channel quality information.

### Claim 18 (depends on 17)

The network node of claim 17, wherein
the network node is a base station having more antenna elements than antenna ports, and
the network node is further configured to:
use a third beam to transmit the reference signal, wherein the third beam is associated with the pre-coder matrix index,
after transmitting the reference signal using the third beam, receive from the first WCD second channel state information comprising the pre-coder matrix index and second channel quality information, and
determine whether to add the third beam to the first set of candidate beams based on the second channel quality information received from the first WCD.

### Claim 19 (depends on 18)

The network node of claim 18, wherein
the network node is further configured to: use a fourth beam to transmit the reference signal, wherein the fourth beam is associated with the pre-coder matrix index, after transmitting the reference signal using the fourth beam, receive from the first WCD third channel state information comprising the pre-coder matrix index and third channel quality information, and determine whether to add the fourth beam to the first set of candidate beams based on the third channel quality information received from the first WCD,
the third beam is angularly shifted with respect to the first beam, and
the fourth beam is angularly shifted with respect to the first beam.

### Claim 20 (depends on 1)

A computer program product comprising a non-transitory computer readable medium storing a computer program comprising instructions which when executed by a data processing apparatus causes the data processing apparatus to perform the method of claim 1.