# US 12,120,048 B2 · Remote interference management reference signal

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- Number: US 12,120,048 B2
- Document ID: US12120048B2
- Status: Granted
- Kind: B2
- Application number: 17/280,707
- Filed: 2019-09-23
- Published: 2021-12-09
- Granted: 2024-10-15
- Earliest claimed: 2018-09-28
- Assignees: Apple Inc.
- Applicants: Apple Inc.
- Inventors: Hassan Ghozlan; Qian Li; Dawei Ying; Geng Wu
- Web page: https://patentgrep.com/patent/US12120048B2

## CPC

- 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 27/261: {Details of reference signals}
- H04J 11/0056: {Inter-base station aspects}
- H04J 13/0062: {Zadoff-Chu}
- H04L 5/0073: {Allocation arrangements that take into account other cell interferences}
- H04L 5/0085: {when channel conditions change}
- H04L 5/0091: {Signalling for the administration of the divided path, e.g. signalling of configuration information}
- H04L 5/14: Two-way operation using the same type of signal, i.e. duplex
- H04L 5/1469: {using time-sharing}
- H04L 27/2605: {Symbol extensions, e.g. Zero Tail, Unique Word [UW]}
- H04W 72/0446: Resources in time domain, e.g. slots or frames
- H04L 27/26025: {Numerology, i.e. varying one or more of symbol duration, subcarrier spacing, Fourier transform size, sampling rate or down-clocking (allocating sub-channels of the transmission path H04L5/003)}
- H04L 27/2607: {Cyclic extensions}
- H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M)
- H04J: MULTIPLEX COMMUNICATION (transmission in general H04B; peculiar to transmission of digital information H04L5/00; systems for the simultaneous or sequential transmission of more than one television signal H04N7/08; in exchanges H04Q11/00; stereophonic systems H04S)
- H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72)

## Abstract

Systems, apparatuses, methods, and computer-readable media are provided for Remote Interference Management (RIM) in wireless networks, including RIM reference signals (RIM-RS) transmitted to assist victim Radio Access Network (RAN) nodes to identify aggressor RAN nodes due to, for example, atmospheric ducting. The RIM-RS is also bandwidth-flexible in order to enable detection of the RIM-RS by aggressor RAN nodes with different bandwidth configurations. Other embodiments may be described and/or claimed.

## Claims

### Claim 1

A base station (BS) comprising:
a radio front end circuitry; and
baseband circuitry coupled to the radio front end circuitry, the baseband circuitry configured to:
generate a Radio Interference Management Reference Signal (RIM-RS), wherein the RIM-RS comprises information about experienced inter-cell interference and a base time domain sequence, including
multiplex one or more component sequences in a frequency domain, wherein a length of a component sequence of the one or more component sequences is less than or equal to a minimum system bandwidth; and
transform the multiplexed component sequences into the base time domain sequence; and
transmit, via the front end circuitry, the RIM-RS to an other BS.

### Claim 2 (depends on 1)

The BS of claim 1, wherein, to generate the RIM-RS, the baseband circuitry is configured to:
generate the base time domain sequence; and
repeat the generation of the base time domain sequence one or more times.

### Claim 3 (depends on 2)

The BS of claim 2, wherein, to generate the RIM-RS, the baseband circuitry is configured to:
generate the RIM-RS to have a same subcarrier spacing (SCS) as a downlink SCS; or
generate the RIM-RS to have a fixed SCS that is different than the downlink SCS.

### Claim 4 (depends on 1)

The BS of claim 1, wherein the RIM-RS comprises a gap period (GP), and the transmission of the RIM-RS occurs at a time location before a maximum downlink transmission boundary within a Time Division Duplex (TDD) downlink (DL) or uplink (UL) period.

### Claim 5 (depends on 1)

The BS of claim 1, wherein the RIM-RS comprises a cyclic prefix (CP), comprising a CP length based on a subcarrier spacing (SCS) configuration.

### Claim 6 (depends on 5)

The BS of claim 5, wherein the CP length is 4.7 us for a 15 SCS, or the CP length is 9.4 μs for a 15 kHz SCS.

### Claim 7 (depends on 1)

The BS of claim 1, wherein the component sequence of the one or more component sequences is a Zadoff-Chu (ZC) sequence, to generate the RIM-RS, the baseband circuitry is configured to:
generate the component sequence according to,
x
u
⁡
(
n
)
=
exp
⁡
(
-
j
⁢
⁢
π
⁢
⁢
un
⁡
(
n
+
1
)
N
ZC
)
wherein xu(n) is the component sequence, n is a number of the one or more component sequences numbered from zero to NZC−1, u is a root index where u ∈{1, . . . , NZC−1}, and NZC is the length of the component sequence and is a largest prime number that is less than or equal to the minimum system bandwidth.

### Claim 8 (depends on 7)

The BS of claim 7, wherein a first and a second component sequence of the one or more component sequences have a same root index, or the first component sequence has a different root index than the second component sequence.

### Claim 9 (depends on 1)

The BS of claim 1, wherein the component sequence of the one or more component sequences comprises a pseudo-noise (PN) sequence and, to generate the RIM-RS, the baseband circuitry is configured to:
generate the component sequence according to,
r
⁡
(
n
)
=
1
2
⁢
(
1
-
2
⁢
c
⁡
(
2
⁢
n
)
)
+
j
⁢
1
2
⁢
(
1
-
2
⁢
c
⁡
(
2
⁢
n
+
1
)
)
wherein r(n) is the component sequence, n is a number of the one or more component sequences numbered from zero to MPN-1, MPN is the length of the component sequence and is less than or equal to the minimum system bandwidth, and c(n) is a length-31 Gold sequence of length MPN.

### Claim 10 (depends on 9)

The BS of claim 9, wherein the PN sequence c(n) is an order-31 (or length-31) Gold sequence of length MPN, where n=0,1, . . . , MPN−1, is defined by:
c(n)=(x1(n+NC)+x2(n+NC)mod 2
x1(n+31)=(x1(n+3)+x1(n))mod 2
x2(n+31)=(x2(n+3)+x2(n+2)+x2(n+1)+x2(n)mod 2
wherein NC=1600, x1(n) is a first m-sequence of the Gold sequence and is initialized with x1(0)=1, x1(n)=0, n=1,2, . . . ,30, x2(n) is a second m-sequence of the Gold sequence denoted as cinit=Σi=030x2(i)·2i wherein cinit is an initial seed value for the second m-sequence x2(n).

### Claim 11 (depends on 9)

The BS of claim 9, wherein cinit=(210f(ntRIM)+nSCID)mod 231 wherein nSCID is a scrambling identity; ntRIM is a number of RIM-RS transmission periods; and
f(ntRIM)=Σ2ic(i) where c(i) is a base pseudo-random sequence initialized with Cinit(i)=(γntRIM+δ)mod 231 where γ is a multiplier factor and δ is an offset.

### Claim 12

A method for a base station (BS) comprising:
generating a Radio Interference Management Reference Signal, (RIM-RS), wherein the RIM-RS comprises information about experienced inter-cell interference and a base time domain sequence, including
multiplexing one or more component sequences in a frequency domain, wherein a length of a component sequence of the one or more component sequences is less than or equal to a minimum system bandwidth; and
transforming the multiplexed component sequences into the base time domain sequence; and
transmitting the RIM-RS to an other BS.

### Claim 13 (depends on 12)

The method of claim 12, further comprising:
mapping the generated RIM-RS sequence to one or more resource blocks; and
generating a time-continuous Orthogonal Frequency Division Multiplexing (OFDM) baseband signal for the RIM-RS sequence, wherein the time-continuous OFDM baseband signal comprises a combination of the one or more resource blocks to which the RIM-RS sequence is mapped.

### Claim 14 (depends on 12)

The method of claim 12, wherein, the generating the RIM-RS comprises:
generating the RIM-RS to have a same subcarrier spacing (SCS), as a downlink SCS; or
generating the RIM-RS to have a fixed SCS that is different than the downlink SCS.

### Claim 15 (depends on 12)

The method of claim 12, wherein the RIM-RS comprises a gap period (GP), and the transmitting the RIM-RS occurs at a time location before a maximum downlink transmission boundary within a Time Division Duplex (TDD) downlink (DL) or uplink (UL) period.

### Claim 16 (depends on 12)

The method of claim 12, wherein the component sequence of the one or more component sequences is a Zadoff-Chu (ZC) sequence, the generating the RIM-RS operation comprises:
generating the component sequence according to,
x
u
⁡
(
n
)
=
exp
⁡
(
-
j
⁢
⁢
π
⁢
⁢
un
⁡
(
n
+
1
)
N
ZC
)
wherein xu(n) is the component sequence, n is a number of the one or more component sequences numbered from zero to NZC−1, u is a root index where u∈{1, . . . , NZC−1}, and NZC is the length of the component sequence and is a largest prime number that is less than or equal to the minimum system bandwidth.

### Claim 17 (depends on 12)

The method claim 12, wherein the component sequence of the one or more component sequences comprises a pseudo-noise (PN) sequence and, the generating the RIM-RS operation comprises:
generating the component sequence according to,
r
⁡
(
n
)
=
1
2
⁢
(
1
-
2
⁢
c
⁡
(
2
⁢
n
)
)
+
j
⁢
1
2
⁢
(
1
-
2
⁢
c
⁡
(
2
⁢
n
+
1
)
)
wherein r(n) is the component sequence, n is a number of the one or more component sequences numbered from zero to MPN−1, MPN is the length of the component sequence and is less than or equal to the minimum system bandwidth, and c(n) is a length-31 Gold sequence of length MPN.

### Claim 18

A non-transitory computer readable medium (CRM) storing instructions that, when executed by a processor of a base station (BS), cause the BS to perform operations, the operations comprising:
generating a Radio Interference Management Reference Signal (RIM-RS), wherein the RIM-RS comprises information about experienced inter-cell interference and a base time domain sequence, including
multiplexing one or more component sequences in a frequency domain, wherein a length of a component sequence of the one or more component sequences is less than or equal to a minimum system bandwidth; and
transforming the multiplexed component sequences into the base time domain sequence; and
transmitting the RIM-RS to an other BS.

### Claim 19 (depends on 18)

The non-transitory CRM of claim 18, wherein the component sequence of the one or more component sequences is a Zadoff-Chu (ZC) sequence, the generating the RIM-RS operation comprises:
generating the component sequence according to,
x
u
⁡
(
n
)
=
exp
⁡
(
-
j
⁢
⁢
π
⁢
⁢
un
⁡
(
n
+
1
)
N
ZC
)
wherein xu(n) is the component sequence, n is a number of the one or more component sequences numbered from zero to NZC−1, u is a root index where u∈{1, . . . , NZC−1}, and NZC is the length of the component sequence and is a largest prime number that is less than or equal to the minimum system bandwidth.

### Claim 20 (depends on 18)

The non-transitory CRM of claim 18, wherein the component sequence of the one or more component sequences comprises a pseudo-noise (PN) sequence and, the generating the RIM-RS operation comprises:
generating the component sequence according to,
r
⁡
(
n
)
=
1
2
⁢
(
1
-
2
⁢
c
⁡
(
2
⁢
n
)
)
+
j
⁢
1
2
⁢
(
1
-
2
⁢
c
⁡
(
2
⁢
n
+
1
)
)
wherein r(n) is the component sequence, n is a number of the one or more component sequences numbered from zero to MPN−1, MPN is the length of the component sequence and is less than or equal to the minimum system bandwidth, and c(n) is a length-31 Gold sequence of length MPN.