# US 12,763,908 B2 · Backward compatible methods for signal energy-saving sleep modes over O-RAN fronthaul interface

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- Number: US 12,763,908 B2
- Document ID: US12763908B2
- Status: Granted
- Kind: B2
- Application number: 18/484,939
- Filed: 2023-10-11
- Published: 2024-04-18
- Granted: 2026-10-13
- Earliest claimed: 2022-10-13
- Assignees: Mavenir Systems, Inc.
- Applicants: Mavenir Systems, Inc.
- Inventors: Sassan Ahmadi; Charles Santhosam Lourdu Raja; John Melvin John William
- Web page: https://patentgrep.com/patent/US12763908B2

## CPC

- H04L 5/0053: {Allocation of signalling, i.e. of overhead other than pilot signals}
- H04W 52/0216: {using a pre-established activity schedule, e.g. traffic indication frame}
- H04W 76/27: Transitions between radio resource control [RRC] states
- 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

A control plane signaling method for reducing energy consumption of O-RAN radio units used in O-RAN CUS and including an O-DU controlling an O-RU via control-plane messaging where a sleep period is extended using a 16-bit binary number that is formed by two reserved octets in Section Type 0, or via an inactivity timer is used to trigger transitions between different sleep states and active states, or via and a bitmap is formed by a reserved octet in Section Type 0 and is used to signal the O-RU to directly transition to different sleep modes.

## Claims

### Claim 1

A control plane signaling method for reducing energy consumption of Open Radio Access Network (O-RAN) radio units used in O-RAN Control, User, and Synchronization planes (O-RAN CUS) and including an O-RAN Distributed Unit (O-DU) controlling a O-RAN Radio Unit (O-RU) via control-plane messaging transmitted on a fronthaul interface, the control plane signaling method comprising steps of:
using Section Type 0 to indicate Physical Resource Block (PRB) blanking of component carriers in a band-sector in a control-plane message transmitted on the fronthaul interface;
wherein in a DownLink (DL) direction when the control-plane message is transmitted from the O-DU to the O-RU, the PRB blanking is performed by the O-DU, and in an UpLink (UL) direction when the control-plane message is transmitted from the O-RU to the O-DU, the PRB blanking is performed the O-RU follows instructions received from the O-DU;
using unused or reserved bits in the control-plane message to indicate transition from an active state to a sleep state for the O-RU;
wherein the sleep state is extended using a 16-bit binary number that is formed by two reserved octets in the Section Type 0.

### Claim 2 (depends on 1)

The control plane signaling method of claim 1, wherein the two reserved octets in the Section Type 0 are 20th and 28th octets.

### Claim 3 (depends on 2)

The control plane signaling method of claim 2, wherein the 20th and 28th octets of the Section Type 0 are used to form a 16-bit binary number.

### Claim 4 (depends on 3)

The control plane signaling method of claim 3, wherein the bits of the 20th octet form a Most Significant Bit (MSB) part and the 28th octet bits form a Least Significant Bit (LSB) part.

### Claim 5 (depends on 1)

The control plane signaling method of claim 1, wherein a sleep period is extended from one Orthogonal Frequency Division Multiplexing (OFDM) symbol to 216 OFDM symbols.

### Claim 6

A control plane signaling method for reducing energy consumption of Open Radio Access Network (O-RAN) radio units used in O-RAN Control, User, and Synchronization planes (O-RAN CUS) and including an O-RAN Distributed Unit (O-DU) controlling a O-RAN Radio Unit (O-RU) via control-plane messaging transmitted on a fronthaul interface, the control plane signaling method comprising steps of:
using Section Type 0 to indicate Physical Resource Block (PRB) blanking of component carriers in a band-sector in a control-plane message transmitted on the fronthaul interface;
wherein in a DownLink (DL) direction when the control-plane message is transmitted from the O-DU to the O-RU, the PRB blanking is performed by the O-DU, and in an UpLink (UL) direction when the control-plane message is transmitted from the O-RU to the O-DU, the PRB blanking is performed the O-RU follows instructions received from the O-DU;
using an inactivity timer located at the O-DU or the O-RU to indicate transition from an active state to a sleep state for the O-RU;
wherein the transition comprises transition to different sleep states for the O-RU and the different sleep states comprise at least four sleep modes, sleep mode 1 (SM1), sleep mode 2 (SM2), sleep mode 3 (SM3), and sleep mode 4 (SM4) where O-RU energy uses extended sleep during at least four extended sleep modes, extended sleep mode 1 (eSM1), extended sleep mode 2 (eSM2), extended sleep mode 3 (eSM3), and extended sleep mode 4 (eSM4) is as follows: eSM4<eSM3<eSM2<eSM1.

### Claim 7 (depends on 6)

The control plane signaling method of claim 6, wherein the transition from one sleep mode to another sleep mode comprises a sequential transition.

### Claim 8 (depends on 6)

The control plane signaling method of claim 6, wherein transition of the O-RU from the active state to the SM1 is triggered by a first period of inactivity (T1) measured by a synchronous timer in the O-DU or the O-RU equal to T1.

### Claim 9 (depends on 8)

The control plane signaling method of claim 8, wherein if the inactivity continues for a second period of inactivity (T2), where T2>T1 upon entering the SM1, the O-RU transitions to the SM2.

### Claim 10 (depends on 9)

The control plane signaling method of claim 9, wherein if the inactivity continues for a third period of inactivity (T3), where T3>T2 upon entering the SM2, the O-RU transitions to the SM3.

### Claim 11 (depends on 10)

The control plane signaling method of claim 10, wherein if the inactivity continues for a fourth period of inactivity (T4), where T4>T3 upon entering the SM3, the O-RU transitions to the SM4.

### Claim 12 (depends on 11)

The control plane signaling method of claim 11, wherein new DL or UL traffic or a new control-plane message from the O-DU to the O-RU triggers transition of the O-RU from any of the at least four extended sleep modes directly to the active state and resets the inactivity timer.

### Claim 13

A control plane signaling method for reducing energy consumption of Open Radio Access Network (O-RAN) radio units used in O-RAN Control, User, and Synchronization planes (O-RAN CUS) and including an O-RAN Distributed Unit (O-DU) controlling a O-RAN Radio Unit (O-RU) via control-plane messaging transmitted on a fronthaul interface, the control plane signaling method comprising steps of:
using Section Type 0 to indicate Physical Resource Block (PRB) blanking of component carriers in a band-sector in a control-plane message transmitted on the fronthaul interface;
wherein in a DownLink (DL) direction when the control-plane message is transmitted from the O-DU to the O-RU, the PRB blanking is performed by the O-DU, and in an UpLink (UL) direction when the control-plane message is transmitted from the O-RU to the O-DU, the PRB blanking is performed the O-RU follows instructions received from the O-DU;
defining a bitmap in the control-plane message formed by a reserved octet in Section Type 0 where the bitmap signals a sleep state for the O-RU to directly transition from an active state to a sleep state for the O-RU;
wherein the bitmap defining a sleep state comprises a first bitmap, the control plane signaling method further comprising a second bitmap defining a length of a sleep cycle.

### Claim 14 (depends on 13)

The control plane signaling method of claim 13, wherein the reserved octet in the Section Type 0 is 20th octet.

### Claim 15 (depends on 14)

The control plane signaling method of claim 14, wherein the sleep states comprise at least four sleep modes, sleep mode 1 (SM1), sleep mode 2 (SM2), sleep mode 3 (SM3), and sleep mode 4 (SM4) where O-RU energy use during the at least four extended sleep modes, extended sleep mode 1 (eSM1), extended sleep mode 2 (eSM2), extended sleep mode 3 (eSM3), extended sleep mode 4 (eSM4) is as follows: eSM4<eSM3<eSM2<eSM1.

### Claim 16 (depends on 15)

The control plane signaling method of claim 15, wherein new DL or UL traffic or a new control-plane message from the O-DU to the O-RU triggers transition of the O-RU from any of the at least four sleep modes directly to the active state and resets an inactivity timer.

### Claim 17 (depends on 15)

The control plane signaling method of claim 15, wherein, a second bitmap is determined by reference to a lookup table; and location of PRBs across frequency are determined by startPrbc and numPrbc parameters.

### Claim 18 (depends on 15)

The control plane signaling method of claim 15, further comprising a timeOffset parameter that is used to indicate a start time of a sleep mode relative to a current time instance where a sleep command is signaled.