# US 9,882,617 B2 · Method and apparatus for reporting precoding information in a communication network

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- Number: US 9,882,617 B2
- Document ID: US9882617B2
- Status: Granted
- Kind: B2
- Application number: 14/901,282
- Filed: 2015-11-16
- Published: 2017-07-13
- Granted: 2018-01-30
- Earliest claimed: 2015-11-16
- Assignees: Telefonaktiebolaget LM Ericsson (publ)
- Applicants: Telefonaktiebolaget L M Ericsson (publ)
- Inventors: Sairamesh Nammi; Thomas Chapman; Bo Göransson; Muhammad Kazmi
- Web page: https://patentgrep.com/patent/US9882617B2

## CPC

- H04B 7/0456: Selection of precoding matrices or codebooks, e.g. using matrices antenna weighting
- H01Q 21/00: Antenna arrays or systems (arrangements for changing or varying the orientation or the shape of the directional pattern of the waves radiated from an antenna or antenna system H01Q3/00)
- H04B 7/0479: {for multi-dimensional arrays, e.g. horizontal or vertical pre-distortion matrix index [PMI]}
- H04B 7/0634: {Antenna weights or vector/matrix coefficients}
- H04B 7/0639: {Using selective indices, e.g. of a codebook, e.g. pre-distortion matrix index [PMI] or for beam selection}
- H04L 67/535: {Tracking the activity of the user (network monitoring arrangements H04L43/00; recording of computer activity G06F11/34)}
- H04W 4/025: {using location based information parameters}
- H04B 7/0689: {using different transmission schemes, at least one of them being a diversity transmission scheme}
- H04B: TRANSMISSION
- H01Q: ANTENNAS, i.e. RADIO AERIALS (radiators or antennas for microwave heating H05B6/72)
- H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M)
- H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72)

## Abstract

In one aspect of this disclosure, a communication device sends first and second precoding reports to a network node by time multiplexing the first and second precoding reports onto a reporting channel in accordance with a multiplexing ratio. The first and second precoding reports comprise first and second precoding recommendations, respectively, and correspond to the first and second dimensions of an antenna array used for transmitting to the communication device. Among other advantages, multiplexing of the first and second reports enables the communication device to reuse a reporting channel and at least some of the underlying reporting protocols or signaling arrangements to report multi-dimensional precoding information. The corresponding network node uses its knowledge of the multiplexing ratio to differentiate between the first and second reports. Moreover, the involved multiplexing ratio may be adapted, either by the network or the communication device, in view of changing operating scenarios.

## Claims

### Claim 1

A method implemented by a communication device configured for operation in a communication network, the method comprising:
receiving transmissions from an antenna array of a network node in the communication network, wherein the antenna array has first and second dimensions;
determining precoding recommendations for transmitting to the communication device from the antenna array, based on evaluating the received transmissions, wherein the precoding recommendations comprise first recommendations pertaining to the first dimension and second recommendations pertaining to the second dimension; and
sending, to the network node by time multiplexing onto a reporting channel, a first number of first precoding reports comprising the first recommendations and a second number of second precoding reports comprising the second recommendations, by time multiplexing in accordance with a particular multiplexing ratio relating the first number and the second number.

### Claim 2 (depends on 1)

The method of claim 1, wherein a reporting cycle comprises N precoding reports sent from the communication device to the network node on the reporting channel, and wherein the particular multiplexing ratio stipulates that M first precoding reports and second precoding reports are sent in every reporting cycle, where N is an integer and M is an integer less than or equal to N.

### Claim 3 (depends on 1)

The method of claim 1, wherein one of the first and second dimensions is prioritized over the other one of the first and second dimensions, and wherein the particular multiplexing ratio reflects the prioritization.

### Claim 4 (depends on 3)

The method of claim 3, further comprising changing the prioritization in dependence on at least one of: control signaling incoming from the communication network; channel conditions at the communication device; and a location of the communication device.

### Claim 5 (depends on 1)

The method of claim 1, further comprising setting the particular multiplexing ratio to a value determined by the communication network.

### Claim 6 (depends on 5)

The method of claim 5, further comprising determining a multiplexing ratio recommendation and sending the multiplexing ratio recommendation to the communication network, for consideration by the communication network in setting the particular multiplexing ratio.

### Claim 7 (depends on 1)

The method of claim 1, further comprising setting the particular multiplexing ratio to a value determined by the communication device in dependence on any one or more of:
an application or service type associated with the communication device;
a mobility profile of the communication device;
historical data corresponding to past usage of one or more multiplexing ratios;
historical or current communication performance of the communication device; and
a current location of the communication device.

### Claim 8 (depends on 7)

The method of claim 7, wherein the mobility profile comprises one or more of:
a Doppler metric or speed of the communication device;
an acceleration of the communication device;
a direction of motion of the communication device;
a change in a location of the communication device.

### Claim 9 (depends on 1)

The method of claim 1, wherein one of the first and second dimensions is a horizontal dimension and the other one of the first and second dimensions is a vertical dimension and, correspondingly, the first precoding reports comprise one of horizontal precoding reports and vertical precoding reports and the second precoding reports comprise the other one of the horizontal precoding reports and the vertical precoding reports.

### Claim 10 (depends on 9)

The method of claim 9, wherein each horizontal precoding report indicates a horizontal precoding matrix recommendation comprising antenna element weights corresponding to the horizontal dimension of the antenna array, and wherein each vertical precoding report indicates a vertical precoding matrix recommendation comprising antenna element weights corresponding to the vertical dimension of the antenna array.

### Claim 11

A communication device configured for operation in a communication network and comprising:
a communication interface circuit configured to receive transmissions from an antenna array of a network node in the communication network, wherein the antenna array has first and second dimensions; and
a processing circuit configured to:
determine precoding recommendations for transmitting to the communication device from the antenna array, based on evaluating the received transmissions, wherein the precoding recommendations comprise first recommendations pertaining to the first dimension and second recommendations pertaining to the second dimension; and
send, to the network node via the communication interface circuit by time multiplexing onto a reporting channel, a first number of first precoding reports comprising the first recommendations and a second number of second precoding reports comprising the second recommendations, by time multiplexing in accordance with a particular multiplexing ratio relating the first number and the second number.

### Claim 12 (depends on 11)

The communication device of claim 11, wherein a reporting cycle comprises N precoding reports sent from the communication device to the network node on the reporting channel, and wherein the particular multiplexing ratio stipulates that M first precoding reports and second precoding reports are sent in every reporting cycle, where N is an integer and M is an integer less than or equal to N.

### Claim 13 (depends on 11)

The communication device of claim 11, wherein one of the first and second dimensions is prioritized over the other one of the first and second dimensions, and wherein the particular multiplexing ratio reflects the prioritization.

### Claim 14 (depends on 13)

The communication device of claim 13, wherein the processing circuit is configured to change the prioritization in dependence on at least one of: control signaling incoming from the communication network; channel conditions at the communication device; and a location of the communication device.

### Claim 15 (depends on 11)

The communication device of claim 11, wherein the processing circuit is configured to set the particular multiplexing ratio to a value determined by the communication network.

### Claim 16 (depends on 15)

The communication device of claim 15, wherein the processing circuit is configured to determine a multiplexing ratio recommendation and send the multiplexing ratio recommendation to the communication network, for consideration by the communication network in setting the particular multiplexing ratio.

### Claim 17 (depends on 11)

The communication device of claim 11, wherein the processing circuit is configured to set the particular multiplexing ratio to a value determined by the processing circuit in dependence on any one or more of:
an application or service type associated with the communication device;
a mobility profile of the communication device;
historical data corresponding to past usage of one or more multiplexing ratios;
historical or current communication performance of the communication device; and
a current location of the communication device.

### Claim 18 (depends on 17)

The communication device of claim 17, wherein the mobility profile comprises one or more of:
a Doppler metric or speed of the communication device;
an acceleration of the communication device;
a direction of motion of the communication device;
a change in a location of the communication device.

### Claim 19 (depends on 11)

The communication device of claim 11, wherein one of the first and second dimensions is a horizontal dimension and the other one of the first and second dimensions is a vertical dimension and, correspondingly, the first precoding reports comprise one of horizontal precoding reports and vertical precoding reports and the second precoding reports comprise the other one of the horizontal precoding reports and the vertical precoding reports.

### Claim 20 (depends on 19)

The communication device of claim 19, wherein each horizontal precoding report indicates a horizontal precoding matrix recommendation comprising antenna element weights corresponding to the horizontal dimension of the antenna array, and wherein each vertical precoding report indicates a vertical precoding matrix recommendation comprising antenna element weights corresponding to the vertical dimension of the antenna array.

### Claim 21

A method implemented by a network node configured for operation in a communication network, the method comprising:
receiving, from a communication device via a reporting channel, precoding reports for use in precoding transmissions to the communication device from an antenna array having first and second dimensions, wherein:
the precoding reports comprise a first number of first precoding reports comprising precoding recommendations pertaining to the first dimension, and a second number of second precoding reports comprising precoding recommendations pertaining to the second dimension; and
the precoding reports are time-multiplexed according to a particular multiplexing ratio relating the first number and the second number;
determining whether individual ones of the precoding reports comprise one of the first precoding reports or comprise one of the second precoding reports, based on the particular multiplexing ratio; and
precoding transmissions to the communication device from the antenna array, according to precoding weights determined in consideration of the precoding recommendations comprising the determined first or second precoding reports.

### Claim 22 (depends on 21)

The method of claim 21, wherein determining whether individual ones of the precoding reports comprise one of the first or second precoding reports further comprises determining whether individual ones of the precoding reports comprise one of the first or second precoding reports based on a reporting cycle over which the particular multiplexing ratio applies, wherein the reporting cycle comprises N precoding reports sent from the communication device on the reporting channel, and wherein the particular multiplexing ratio stipulates that M first precoding reports and second precoding reports are sent in every reporting cycle, where N is an integer and M is an integer less than or equal to N.

### Claim 23 (depends on 21)

The method of claim 21, further comprising indicating the particular multiplexing ratio via signaling sent to the communication device.

### Claim 24 (depends on 21)

The method of claim 21, further comprising receiving a multiplexing ratio recommendation from the communication device, and setting the particular multiplexing ratio in consideration of the multiplexing ratio recommendation.

### Claim 25 (depends on 21)

The method of claim 21, further comprising setting the particular multiplexing ratio in dependence on a prioritization between the first and second dimensions of the antenna array.

### Claim 26 (depends on 25)

The method of claim 25, further comprising determining the prioritization in dependence on at least one of: channel conditions at the communication device; and a location of the communication device.

### Claim 27 (depends on 21)

The method of claim 21, further comprising setting the particular multiplexing ratio in dependence on any one or more of:
an application or service type associated with the communication device;
a mobility profile of the communication device;
historical data corresponding to past usage of one or more multiplexing ratios;
historical or current communication performance of the communication device; and
a current location of the communication device.

### Claim 28 (depends on 27)

The method of claim 27, wherein the mobility profile comprises one or more of:
a Doppler metric or speed of the communication device;
an acceleration of the communication device;
a direction of motion of the communication device;
a change in a location of the communication device.

### Claim 29 (depends on 21)

The method of claim 21, wherein the particular multiplexing ratio defines a pattern of first and second precoding reports within a reporting cycle, and wherein determining whether individual ones of the precoding reports comprise one of the first precoding reports or comprise one of the second precoding reports comprises receiving a given precoding report, determining a position of the given precoding report within the pattern, and determining whether the position corresponds to the first precoding reports or to the second precoding reports.

### Claim 30

A network node configured for operation in a communication network and comprising:
a communication interface circuit configured to receive, from a communication device via a reporting channel, precoding reports for use in precoding transmissions to the communication device from an antenna array having first and second dimensions, wherein:
the precoding reports comprise a first number of first precoding reports comprising precoding recommendations pertaining to the first dimension, and a second number of second precoding reports comprising precoding recommendations pertaining to the second dimension; and
the precoding reports are time-multiplexed according to a particular multiplexing ratio relating the first number and the second number; and
a processing circuit configured to:
determine whether individual ones of the precoding reports comprise one of the first precoding reports or comprise one of the second precoding reports, based on the particular multiplexing ratio; and
precode transmissions to the communication device from the antenna array, according to precoding weights determined in consideration of the precoding recommendations comprising the determined first or second precoding reports.

### Claim 31 (depends on 30)

The network node of claim 30, wherein the processing circuit is configured to determine whether individual ones of the precoding reports comprise one of the first or second precoding reports based on a reporting cycle over which the particular multiplexing ratio applies, wherein the reporting cycle comprises N precoding reports sent from the communication device on the reporting channel, and wherein the particular multiplexing ratio stipulates that M first precoding reports and second precoding reports are sent in every reporting cycle, where N is an integer and M is an integer less than or equal to N.

### Claim 32 (depends on 30)

The network node of claim 30, wherein the processing circuit is configured to indicate the particular multiplexing ratio via signaling sent to the communication device.

### Claim 33 (depends on 30)

The network node of claim 30, wherein the processing circuit is configured to receive a multiplexing ratio recommendation from the communication device, and set the particular multiplexing ratio in consideration of the multiplexing ratio recommendation.

### Claim 34 (depends on 30)

The network node of claim 30, wherein the processing circuit is configured to set the particular multiplexing ratio in dependence on a prioritization between the first and second dimensions of the antenna array.

### Claim 35 (depends on 34)

The network node of claim 34, wherein the processing circuit is configured to determine the prioritization in dependence on at least one of: channel conditions at the communication device; and a location of the communication device.

### Claim 36 (depends on 30)

The network node of claim 30, wherein the processing circuit is configured to set the particular multiplexing ratio in dependence on any one or more of:
an application or service type associated with the communication device;
a mobility profile of the communication device;
historical data corresponding to past usage of one or more multiplexing ratios;
historical or current communication performance of the communication device; and
a current location of the communication device.

### Claim 37 (depends on 36)

The network node of claim 36, wherein the mobility profile comprises one or more of:
a Doppler metric or speed of the communication device;
an acceleration of the communication device;
a direction of motion of the communication device;
a change in a location of the communication device.

### Claim 38 (depends on 30)

The network node of claim 30, wherein the particular multiplexing ratio defines a pattern of first and second precoding reports within a reporting cycle, and wherein the processing circuit is configured to determine whether individual ones of the precoding reports comprise one of the first precoding reports or comprise one of the second precoding reports based on receiving a given precoding report, determining a position of the given precoding report within the pattern, and determining whether the position corresponds to the first precoding reports or to the second precoding reports.
