# US 2018/0324007 A1 · Employing modulation layer mapping to improve performance of mimo communication systems

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- Number: US 2018/0324007 A1
- Document ID: US20180324007A1
- Status: Published application
- Kind: A1
- Application number: 15/586,994
- Filed: 2017-05-04
- Published: 2018-11-08
- Earliest claimed: 2017-05-04
- Assignees: AT&T Intellectual Property I, L.P.
- Applicants: AT&T Intellectual Property I, L.P.
- Inventors: SaiRamesh Nammi; Arunabha Ghosh; Xiaoyi Wang
- Web page: https://patentgrep.com/patent/US20180324007A1

## CPC

- H04L 25/03929: {with layer mapping, e.g. codeword-to layer design (for space-time coding H04L1/0618)}
- H04B 7/0482: {Adaptive codebooks}
- H04B 7/0626: {Channel coefficients, e.g. channel state information [CSI]}
- H04B 7/063: {Parameters other than those covered in groups H04B7/0623 - H04B7/0634, e.g. channel matrix rank or transmit mode selection}
- H04L 1/0003: {by switching between different modulation schemes}
- H04L 1/0009: {by adapting the channel coding (H04L1/1812 takes precedence)}
- H04L 1/0026: {Transmission of channel quality indication}
- H04L 1/06: using space diversity
- H04L 25/0204: {of multiple channels}
- H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M)
- H04B: TRANSMISSION

## Abstract

The disclosed subject matter relates to employing modulation layer mapping to improve the performance of multiple-input and multiple-output (MIMO) communication systems. In one embodiment, a method comprises determining, by a device comprising a processor, codeword information in association with establishment of a wireless communication link with a network device of a wireless communication network, wherein the device and the network device are configured to communicate via the communication link using a MIMO communication scheme. The determining the codeword information comprises determining a code rate and determining a number of modulation indexes for the code rate based on signal-to-noise ratios respectively associated with channel layers included in the MIMO communication scheme. The method further comprises sending, by the device, the codeword information to the network device via a control channel of the wireless communication link.

## Claims

### Claim 1

A device, comprising:
a processor; and
a memory that stores executable instructions that, when executed by the processor, facilitate performance of operations, comprising:
determining codeword information in association with a wireless communication link with a network device of a wireless communication network, wherein the device and the network device are configured to communicate via the wireless communication link using a multiple-input and multiple-output communication protocol, and wherein the determining the codeword information comprises:
determining a code rate,
determining modulation indexes for the code rate based on channel state information for channel layers included in the multiple-input and multiple-output communication protocol, and
determining mapping information for the code rate that maps the modulation indexes to respective channel layers of the channel layers; and
sending the codeword information to the network device via a control channel of the wireless communication link.

### Claim 2 (depends on 1)

The device of claim 1, wherein the operations further comprise:
based on the sending the codeword information, receiving data from the network device in accordance with a scheduling configuration determined based on the codeword information.

### Claim 3 (depends on 1)

The device of claim 1, wherein the channel state information comprises signal-to-noise ratios associated with the respective channel layers.

### Claim 4 (depends on 1)

The device of claim 1, wherein the determining the modulation indexes comprises determining a number of the modulation indexes based on signal-to-noise ratios associated with the respective channel layers.

### Claim 5 (depends on 1)

The device of claim 1, wherein the determining the mapping comprises mapping the respective modulation indexes to the respective channel layers based on signal-to-noise ratios associated with the respective channel layers.

### Claim 6 (depends on 1)

The device of claim 1, wherein the determining the modulation indexes comprises:
determining a first layer of the respective channel layers associated with a lowest signal-to-noise ratio relative to other layers of the respective channel layers other than the first layer; and
determining a first modulation index of the modulation indexes based on the lowest signal-to-noise ratio, and
wherein the determining the mapping information comprises associating the first layer with the first modulation index.

### Claim 7 (depends on 6)

The device of claim 6, wherein the determining the modulation indexes further comprises:
determining a second modulation index of the modulation indexes based on a higher signal-to-noise ratio that is higher than the lowest signal-to-noise ratio and that is associated with a second layer of the respective channel layers, and
wherein the determining the mapping information comprises associating the second layer with the second modulation index.

### Claim 8 (depends on 1)

The device of claim 1, wherein the determining the modulation indexes comprises determining a first modulation index and a second modulation index, and wherein the determining the mapping information comprises:
determining a first group of layers of the respective channel layers for association with the first modulation index; and
determining a second group of layers of the respective channels layers for association with the second modulation index.

### Claim 9 (depends on 1)

The device of claim 1, wherein the code rate comprises a first code rate, wherein the modulation indexes comprise first modulation indexes, wherein the mapping information comprises first mapping information, and wherein the determining the codeword information further comprises:
determining a second code rate,
determining second modulation indexes for the code rate based on the channel state information, and
determining second mapping information for the second code rate that maps respective second modulation indexes of the second modulation indexes to the respective channel layers.

### Claim 10 (depends on 1)

The device of claim 1, wherein the determining the code rate comprises determining code rates, and wherein the determining the code rates comprises determining a number of the code rates based on a transmission rank of the device.

### Claim 11 (depends on 10)

The device of claim 10, wherein the determining the number of the code rates comprises determining the number as a defined function of the transmission rank.

### Claim 12 (depends on 10)

The device of claim 10, wherein the determining the number of the code rates further comprises determining the number based on the channel state information.

### Claim 13

A method, comprising:
determining, by a device comprising a processor, codeword information in connection with an establishment of a wireless communication link with a network device of a wireless communication network, wherein the device and the network device are configured to communicate via the wireless communication link using a multiple-input multiple-output communication scheme, and wherein the determining the codeword information comprises:
determining a code rate, and
determining a number of modulation indexes for the code rate based on signal-to-noise ratios respectively associated with channel layers included in the multiple-input multiple-output communication scheme; and
sending, by the device, the codeword information to the network device via a control channel of the wireless communication link.

### Claim 14 (depends on 13)

The method of claim 13, further comprising:
based on the sending the codeword information, receiving, by the device from the network device, data in accordance with a scheduling configuration determined based on the codeword information.

### Claim 15 (depends on 13)

The method of claim 13, wherein the determining the number of modulation indexes comprises determining a modulation index for the code rate, and wherein the determining the codeword information further comprises:
determining a value for the modulation index based on the signal-to-noise ratios respectively associated with the channel layers; and
assigning the modulation index to a layer of the channel layers based on the signal-to-noises ratios.

### Claim 16 (depends on 13)

The method of claim 13, wherein the determining the number of modulation indexes comprises determining modulation indexes for the code rate, and wherein the determining the codeword information further comprises:
determining mapping information that respectively maps the modulation indexes to different layers of the channel layers based on the signal-to-noise ratios respectively associated with channel layers.

### Claim 17 (depends on 13)

The method of claim 13, wherein the determining the code rate comprises determining code rates, and wherein the determining the code rates comprises determining a number of the code rates based on a transmission rank of the device.

### Claim 18

A method, comprising:
receiving, by a network device comprising a processor, codeword information from a device associated with a wireless communication link established between the network device and the device,
wherein the device and the network device communicate via the wireless communication link using a multiple input multiple output communication standard, and
wherein the codeword information identifies, code rates, modulation indexes for each code rate of the code rates, and respective channel layers included in the multiple input multiple output communication standard assigned to the modulation indexes; and
scheduling, by the network device, data transmissions sent from the network device to the device based on scheduling parameters determined based on the codeword information.

### Claim 19 (depends on 18)

The method of claim 18, wherein the receiving the codeword information comprises receiving the codeword information via a control channel associated with the wireless communication link in association with reception of channel state information received by the network device from the device via the control channel.

### Claim 20 (depends on 19)

The method of claim 19, further comprising:
determining, by the network device, the scheduling parameters based on the codeword information and the channel state information.