# US 12,003,439 B2 · Methods and apparatus for multi-carrier communication systems with adaptive transmission and feedback

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- Number: US 12,003,439 B2
- Document ID: US12003439B2
- Status: Granted
- Kind: B2
- Application number: 17/831,878
- Filed: 2022-06-03
- Published: 2022-09-22
- Granted: 2024-06-04
- Earliest claimed: 2004-02-13
- Assignees: Neo Wireless LLC
- Applicants: Neo Wireless LLC
- Inventors: Xiaodong Li; Titus Lo; Kemin Li; Haiming Huang
- Web page: https://patentgrep.com/patent/US12003439B2

## CPC

- H04L 5/0044: {Allocation of payload; Allocation of data channels, e.g. PDSCH or PUSCH}
- H04B 7/0413: MIMO systems
- H04L 1/0026: {Transmission of channel quality indication}
- H04L 1/0029: {Reduction of the amount of signalling, e.g. retention of useful signalling or differential signalling (power control H04W52/04)}
- H04L 1/0068: {by puncturing}
- H04L 1/0073: {Special arrangements for feedback channel}
- H04L 5/0007: {the frequencies being orthogonal, e.g. OFDM(A) or DMT}
- H04L 5/0046: {Determination of the number of bits transmitted on different sub-channels}
- H04L 5/0048: {Allocation of pilot signals, i.e. of signals known to the receiver (allocation of control signalling H04L5/0053; use of control signalling H04L5/0091)}
- H04L 5/006: {Quality of the received signal, e.g. BER, SNR, water filling}
- H04W 72/044: based on the type of the allocated resource
- H04W 72/20: Control channels or signalling for resource management
- H04L 1/0003: {by switching between different modulation schemes}
- H04L 1/0009: {by adapting the channel coding (H04L1/1812 takes precedence)}
- H04L 5/0091: {Signalling for the administration of the divided path, e.g. signalling of configuration information}
- H04W 52/26: using transmission rate or quality of service QoS [Quality of Service]
- H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M)
- H04B: TRANSMISSION
- H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72)

## Abstract

An arrangement is disclosed where in a multi-carrier communication system, the modulation scheme, coding attributes, training pilots, and signal power may be adjusted to adapt to channel conditions in order to maximize the overall system capacity and spectral efficiency without wasting radio resources or compromising error probability performance, etc.

## Claims

### Claim 1

A first device served by a second device using Orthogonal Frequency Division Multiplexing (OFDM) and utilizing OFDM symbols grouped in a time domain into time intervals, each time interval having a plurality of OFDM symbols, and subcarriers grouped in a frequency domain into blocks, each block having a plurality of consecutive subcarriers, the first device comprising:
a transmitter; and
a receiver, wherein:
the receiver is configured to receive a control message on a forward link from the second device, and the control message includes a single value that indicates a modulation scheme of a plurality of modulation schemes and a pilot pattern of a plurality of pilot patterns to use in at least two blocks of the blocks of subcarriers over a time interval; and
the transmitter is configured to transmit a reverse link signal over the at least two blocks of subcarriers over the plurality of OFDM symbols of the time interval, each block of the at least two blocks has the indicated modulation scheme and contains the indicated pilot pattern, and at least one of the plurality of OFDM symbols of the time interval includes data on some of the plurality of consecutive subcarriers and pilots on others of the plurality of consecutive subcarriers of each block of the at least two blocks.

### Claim 2 (depends on 1)

The first device of claim 1 wherein when a first pilot pattern of the plurality of pilot patterns is applied to the at least two blocks of subcarriers, pilots are located at both edge subcarriers in frequency of each block of the at least two blocks of subcarriers and when a second pilot pattern of the plurality of pilot patterns is applied to the at least two blocks of subcarriers, pilots are not located at one of the edge subcarriers in frequency of each block of the at least two blocks of subcarriers.

### Claim 3 (depends on 1)

The first device of claim 1 wherein the plurality of modulation schemes include QPSK, 16-QAM and 64-QAM.

### Claim 4 (depends on 1)

The first device of claim 1 wherein the indicated pilot pattern is based on channel conditions.

### Claim 5 (depends on 4)

The first device of claim 4 wherein the indicated modulation scheme is based on the channel conditions.

### Claim 6 (depends on 1)

The first device of claim 1 wherein pilots of each pilot pattern of the plurality of pilot patterns are present in a subset of OFDM symbols in time of the plurality of OFDM symbols in time of the time interval.

### Claim 7 (depends on 1)

The first device of claim 1 wherein the receiver is further configured to receive an indication of the at least two blocks in which to transmit the reverse link signal.

### Claim 8 (depends on 1)

The first device of claim 1 wherein the receiver is further configured to receive an indication of a duration of the time interval.

### Claim 9 (depends on 1)

The first device of claim 1 wherein the time intervals are time slots.

### Claim 10 (depends on 1)

The first device of claim 1 wherein the receiver is further configured to receive information that indicates whether the at least two blocks of subcarriers used to transmit the reverse link signal are adjacent in frequency or separated in frequency.

### Claim 11 (depends on 1)

The first device of claim 1 wherein the receiver is further configured to receive an indication of a power level to be used by the transmitter for a reverse link transmission.

### Claim 12 (depends on 11)

The first device of claim 11 wherein the indication of a power level provides an absolute power level to set the current power level and a relative amount to increase the current power level.

### Claim 13 (depends on 1)

The first device of claim 1, wherein the time interval is a first time interval, and further wherein:
the receiver is further configured to receive a second control message on the forward link from the second device, the second control message includes a single value that indicates a second modulation scheme of the plurality of modulation schemes and a second pilot pattern of the plurality of pilot patterns to use for in multiple blocks of the blocks of subcarriers over a second time interval; and
the transmitter is further configured to transmit a second reverse link signal over the multiple blocks of subcarriers over the plurality of OFDM symbols of the second time interval, wherein each block of the multiple blocks has the indicated second modulation scheme and contains the indicated second pilot pattern;
wherein the first pilot pattern and the second pilot pattern respectively specify locations of pilots on a time-frequency grid defined for each block of subcarriers over the plurality of OFDM symbols of the time interval, and wherein the first pilot pattern specifies, on the corresponding time-frequency grid and for a first OFDM symbol of the corresponding time-frequency grid, pilots on more subcarriers than the second pilot pattern specifies, and further wherein the remaining subcarriers for the first OFDM symbol of the corresponding time-frequency grid are used for data, such that more subcarriers of the block for the first OFDM symbol are used for data when using the first pilot pattern than when using the second pilot pattern; and
wherein the number of subcarriers in each block of the multiple blocks is the same as the number of subcarriers in each block of the at least two blocks and the duration of the first time interval is the same as the duration of the second time interval.

### Claim 14 (depends on 1)

The first device of claim 1 wherein for one or more OFDM symbols in time that includes pilots in the indicated pilot pattern, a second pilot pattern of the plurality of pilot patterns includes pilots on a different number of subcarriers than the indicated pilot pattern.

### Claim 15 (depends on 1)

The first device of claim 1 wherein the pilot pattern is a first pilot pattern and the reverse link signal is a first reverse link signal, and further wherein:
in the time interval, at least one block of other blocks of the blocks of subcarriers includes a second reverse link signal that includes a second pilot pattern that is different than the first pilot pattern, and wherein the first pilot pattern and the second pilot pattern are suited for respective channel conditions.

### Claim 16

A first device serving at least a second device and a third device using Orthogonal Frequency Division Multiplexing (OFDM) and utilizing OFDM symbols grouped in a time domain into time intervals, each time interval having a plurality of OFDM symbols, and subcarriers grouped in a frequency domain into blocks, each block having a plurality of consecutive subcarriers, the first device comprising:
a transmitter; and
a receiver, wherein:
the transmitter is configured to transmit a control message on a forward link to the second device and to the third device, and the control message includes a single first value that indicates a first modulation scheme of a plurality of modulation schemes and a first pilot pattern of a plurality of pilot patterns for the second device to use in at least two blocks of the blocks of subcarriers over a time interval, and the control message includes a second single value that indicates a second modulation scheme of the plurality of modulation schemes and a second pilot pattern of the plurality of pilot patterns for the third device to use in two or more blocks of subcarriers over the time interval; and
the receiver is further configured to:
receive a first reverse link signal from the second device over the at least two blocks in over the plurality of OFDM symbols of the time interval, and each block of the at least two blocks has the indicated first modulation scheme and contains the indicated first pilot pattern; and
receive a second reverse link signal from the third device over the two or more blocks over the plurality of OFDM symbols of the time interval, and each block of the two or more blocks has the indicated second modulation scheme and contains the indicated second pilot pattern; and
at least one of the plurality of OFDM symbols of the time interval includes data on some of the plurality of consecutive subcarriers and pilots on others of the plurality of consecutive subcarriers of each block of the at least two blocks and each block of the two or more blocks.

### Claim 17 (depends on 1)

The first device of claim 1 wherein when the first pilot pattern of the plurality of pilot patterns is applied to the at least two blocks of subcarriers, pilots are located at both edge subcarriers in the at least two blocks of subcarriers and when the second pilot pattern of the plurality of pilot patterns is applied to the two or more blocks of subcarriers, pilots are not located at one of the edge subcarriers in the two or more blocks of subcarriers.

### Claim 18 (depends on 16)

The first device of claim 16 wherein the plurality of modulation schemes include QPSK, 16-QAM and 64-QAM.

### Claim 19 (depends on 16)

The first device of claim 16 wherein the indicated first pilot pattern and the indicated second pilot pattern are based on respective channel conditions.

### Claim 20 (depends on 19)

The first device of claim 19 wherein the indicated first modulation scheme and the indicated second modulation scheme are based on the respective channel conditions.

### Claim 21 (depends on 16)

The first device of claim 16 wherein pilots of each pilot pattern of the plurality of pilot patterns are present in a subset of OFDM symbols in time of a set the plurality of OFDM symbols in time of the time interval.

### Claim 22 (depends on 16)

The first device of claim 16 wherein the transmitter is further configured to transmit an indication of the at least two blocks in which to receive the first reverse link signal and an indication of the two or more blocks in which to receive the second reverse link signal.

### Claim 23 (depends on 16)

The first device of claim 16 wherein the transmitter is further configured to transmit an indication of a duration of the time interval.

### Claim 24 (depends on 16)

The first device of claim 16 wherein the time intervals are time slots.

### Claim 25 (depends on 16)

The first device of claim 16 wherein the transmitter is further configured to transmit information that indicates whether the at least two blocks of subcarriers used to receive the first reverse link signal are adjacent in frequency or separated in frequency.

### Claim 26 (depends on 16)

The first device of claim 16 wherein the transmitter is further configured to transmit an indication of a power level to be used by the second device for a reverse link transmission.

### Claim 27 (depends on 26)

The first device of claim 26 wherein the indication of a power level provides an absolute power level to set the current power level and a relative amount to increase the current power level.

### Claim 28 (depends on 16)

The first device of claim 16, wherein the time interval is a first time interval, and further wherein:
the transmitter is further configured to transmit a second control message on the forward link to the second device, the second control message includes a single value that indicates a third modulation scheme of the plurality of modulation schemes and a third pilot pattern of the plurality of pilot patterns for the second device to use in multiple blocks of the blocks of subcarriers over a second time interval; and
the receiver is further configured to receive a third reverse link signal from the second device over the multiple blocks of subcarriers over the plurality of OFDM symbols of the second time interval, wherein each block of the multiple blocks has the indicated third modulation scheme and contains the indicated third pilot pattern;
wherein the number of subcarriers in each block of the multiple blocks is the same as the number of subcarriers in each block of the at least two blocks and the duration of the first time interval is the same as the duration of the second time interval.

### Claim 29 (depends on 16)

The first device of claim 16 wherein for one or more OFDM symbols in time that includes pilots in the first pilot pattern, the second pilot pattern of the plurality of pilot patterns includes pilots on a different number of subcarriers than the first pilot pattern.

### Claim 30 (depends on 16)

The first device of claim 16 wherein:
the first pilot pattern and the second pilot pattern respectively specify locations of pilots on a time-frequency grid defined for each block of subcarriers over the plurality of OFDM symbols of the time interval, and wherein the first pilot pattern specifies, on the corresponding time-frequency grid and for a first OFDM symbol of the corresponding time-frequency grid, pilots on more subcarriers than the second pilot pattern specifies, and further wherein the remaining subcarriers for the first OFDM symbol of the corresponding time-frequency grid are used for data, such that more subcarriers of the block for the first OFDM symbol are used for data when using the first pilot pattern than when using the second pilot pattern; and
the first pilot pattern and the second pilot pattern are suited for respective channel conditions.