5BACKWARD COMPATIBLE METHODS FOR SIGNALING ENERGY-SAVING SLEEP MODES OVER O-RAN FRONTHAUL INTERFACE
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.
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 method comprising the 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.
2 . The control plane signaling method of claim 1 , wherein the sleep state is extended using a 16-bit binary number that is formed by two reserved octets in Section Type 0.
3 . The control plane signaling method of claim 2 , wherein the two reserved octets in Section Type 0 are the 20th and 28th octets.
4 . The control plane signaling method of claim 3 , wherein the 20th and 28th octets of Section Type 0 are used to form a 16-bit binary number.
5 . The control plane signaling method of claim 4 , wherein the 20th octet bits form a Most Significant Bit (MSB) part and the 28th octet bits form a Least Significant Bit (LSB) part.
6 . The control plane signaling method of claim 1 , wherein the sleep period is extended from one Orthogonal Frequency Division Multiplexing (OFDM) symbol to 216 OFDM symbols.
7 . 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 method comprising the 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.
8 . The control plane signaling method of claim 7 , wherein the transition comprises transition to different sleep states for the O-RU.
9 . The control plane signaling method of claim 8 , wherein different sleep states comprise at least four sleep modes (SM1, SM2, SM3, SM4) where O-RU energy use during the at least four sleep modes (eSM1, eSM2, eSM3, eSM4) is as follows: eSM4<eSM3<eSM2<eSM1.
10 . The control plane signaling method of claim 9 , wherein the transition from one sleep mode to another sleep mode comprises a sequential transition.
11 . The control plane signaling method of claim 9 , wherein 0-RU transition from an active state to 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.
12 . The control plane signaling method of claim 11 , wherein if the inactivity continues for a second period of inactivity (T2), where T2>T1 upon entering SM1, the O-RU transitions to SM2.
13 . The control plane signaling method of claim 12 , wherein if the inactivity continues for a third period of inactivity (T3), where T3>T2 upon entering SM2, the O-RU transitions to SM3.
14 . The control plane signaling method of claim 13 , wherein if the inactivity continues for a fourth period of inactivity (T4), where T4>T3 upon entering SM3, the O-RU transitions to SM4.
15 . The control plane signaling method of claim 14 , 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 the inactivity timer.
16 . 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 method comprising the 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.
17 . The control plane signaling method of claim 16 , wherein the bitmap defining a sleep state comprises a first bitmap, the methods comprising a second bitmap defining a length of a sleep cycle.
18 . The control plane signaling method of claim 17 , wherein the reserved octet in Section Type 0 is the 20th octet.
19 . The control plane signaling method of claim 18 , wherein the sleep states comprises at least four sleep modes (SM1, SM2, SM3, SM4) where O-RU energy use during the at least four sleep modes (eSM1, eSM2, eSM3, eSM4) is as follows: eSM4<eSM3<eSM2<eSM1.
20 . The control plane signaling method of claim 19 , 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 the inactivity timer.
21 . The control plane signaling method of claim 19 , wherein,
the second bitmap is determined by reference to a lookup table; and
location of PRBs across frequency are determined by startPrbc and numPrbc parameters.
22 . The control plane signaling method of claim 19 , wherein a timeOffset parameter is used to indicate a start time of a sleep mode relative to the current time instance where a sleep command is signaled.