Radio unit (RU) power information feedback to distributed unit (DU) in open radio access network (ORAN) for terminal initial access

Abstract

In an Open Radio Access Network (ORAN) communication system including Radio Units (RUs), Distributed Units (DUs), and a central unit (CU), the DU to determines a power parameter identified in a system broadcast message that is broadcasted by the RU. In some situations, the power information is received from at the DU from the RU over a fronthaul. The power information is based on received power conditions of transmissions from terminals within the RU service area. The DU sets the reference power parameter such that received power level of initial access signals transmitted from terminals using the power parameter facilitate reception at the RU at a target power level. A terminal receives the system broadcast message and applies the power parameter to set a transmission power level of an initial access request transmission, such as a connection request message transmitted over the Random-Access Channel (RACK) to the RU.

Description

RADIO UNIT (RU) POWER INFORMATION FEEDBACK TO DISTRIBUTED UNIT (DU) IN OPEN RADIO ACCESS NETWORK (ORAN) FOR TERMINAL INITIAL ACCESSCLAIM OF PRIORITY

[0001] The present application claims priority to Provisional Application No. 63 / 568,138, entitled “Method to Improve the Initial Access in ORAN Systems”, filed March 21 , 2024, assigned to the assignee hereof and hereby expressly incorporated by reference in its entirety.FIELD

[0002] This invention generally relates to wireless communications and more particularly to Radio Unit (RU) power information feedback to a Distributed Unit (DU) in an Open Radio Access Network (ORAN) for terminal initial access.BACKGROUND

[0003] Wireless communication systems provide wireless communication services to terminals and can be organized into three functional blocks including a Radio Unit (RU), a Distributed Unit (DU) and a Centralized Unit (CU). The RU transmits, receives, amplifies, and digitizes radio frequency signals and typically located near, or integrated into, the antenna. The RU transmits downlink signals to terminals and receives uplink signals from the terminals. The DU and CU perform computations and / or processing to send and receive digitalized radio signals to and from the core network. The DU is typically located at or near the RU and the CU may be closer to the core network. The infrastructure or connection between the RU and the DU is often referred to as fronthaul and the infrastructure or connection between the DU and the CU is often referred to as a midhaul. Although such an architecture can be utilized with proprietary equipment in Radio Access Network, the functionality can be exploited in an Open Radio Access Network (ORAN). An ORAN is a nonproprietary version of the Radio Access Network(RAN) where interoperation between cellular network equipment provided by different manufacturers. The ORAN structure allows for a standard interface between the Rll and DU such that different vendors may provide equipment for the two functional blocks.SUMMARY

[0004] In an Open Radio Access Network (ORAN) communication system including Radio Units (RUs), Distributed Units (DUs), and a central unit (CU), the DU to determines a power parameter identified in a system broadcast message that is broadcasted by the RU. In some situations, the power information is received from at the DU from the RU over a fronthaul. The power information is based on received power conditions of transmissions from terminals within the RU service area. The DU sets the reference power parameter such that received power level of initial access signals transmitted from terminals using the power parameter facilitate reception at the RU at a target power level. A terminal receives the system broadcast message and applies the power parameter to set a transmission power level of an initial access request transmission, such as a connection request message transmitted over the Random- Access Channel (RACH) to the RU.BRIEF DESCRIPTION OF THE DRAWINGS

[0005] FIG. 1 A is a block diagram of an Open Radio Access Network (ORAN) system for an example where a Radio Unit (RU) sends power information to a Distributed Unit (DU) and the DU adjusts power parameters based on the power information.

[0006] FIG. 1 B is a block diagram of an ORAN system for an example where the DU sets a power parameter in SIB1s transmitted from different RUs to different values based on power information specific to each RU.

[0007] FIG. 2 is a block diagram of an example of a RU connected to the DU suitable for use in the example of FIG. 1 A and FIG. 1 B.

[0008] FIG. 3 is a block diagram of an example of a UE device suitable for use as a terminal device.

[0009] FIG. 4 is a messaging diagram for an example where the RU provides power information to the DU.

[0010] FIG. 5A is a flowchart of an example of power management performed at an RU of an ORAN system for initial network access transmissions from terminals.

[0011] FIG. 5B is a flowchart of an example of performing power information determination and reporting at an RU where the RU monitors conditions and reports the power information to the DU in response to a power information request received from the DU.

[0012] FIG. 6 is a flow chart of an example of power management performed at a DU of an ORAN system for initial network access transmissions from terminals.DETAILED DESCRIPTION

[0013] As discussed above, a RAN may be organized into three functional blocks including a Radio Unit (RU), a Distributed Unit (DU) and a Centralized Unit (CU) wherein the RU wirelessly transmits downlink signals to and wirelessly receives uplink signals from terminals. A terminal communication device (terminal), such as a remote terminal and a relay terminal, is a communication device on the terminal side of the communication system and is sometimes referred to as user equipment (UE), a UE device, a terminal device, wireless mobile device, wireless communication device and other terms. Some examples of a terminal communication device include a mobile phone, a smart phone, a personal digital assistant (PDA), tablet, and laptop computer. In some situations, the terminal communication device is a machine type communication (MTC) communication device or Internet-of-Things (loT) device. In addition, the terminal communication device may be, or may be a part of, a wearable device or a vehicle where the vehicle may be a terrestrial vehicle, watercraft, or aircraft (including unmanned aerial vehicles). The terminal communication device, therefore, isany fixed, mobile, or portable equipment that performs the functions of the terminal device described herein.

[0014] Some distributed RAN systems, such as ORAN systems, apply the standard communication specifications originally designed for conventional RANs where a gNB provides at least some of functions of both the RU and DU. As a result, the distributed architecture of an ORAN system may experience drawbacks. In one particular example, 3GPP communication specification techniques facilitating efficient power control for initial terminal access experience limitations due to the separation of conventional functions of the gNB between the RU and DU and due to including an interface between the two infrastructure blocks.

[0015] The limitations revolve around the critical aspect of terminal (User Equipment (UE)) power control during the initial access phase in cellular networks, particularly within the context of Open Radio Access Networks (ORAN). Initial network access of a terminal involves an attempt by the terminal to establish a connection with the network by transmitting a Random-Access Channel (RACH) preamble sequence. A significant challenge in this process is determining the optimal transmit power level for the RACH preamble. Without precise power level settings, there is a risk of either insufficient of excessive transmission power. If the power is too low, the terminal may suffer multiple failed access attempts, or it may take too long to access the network, thus impairing the performance for low-latency applications. A transmission power that is too high results in unnecessary battery drain and potential interference with other transmissions.

[0016] Conventional networks with base stations (gNBs) implement a power-ramping mechanism, allowing the terminal to transmit the RACH preamble sequence multiple times with incrementally increased transmit power. This approach relies on the powerRampingStep parameter from the System Information Block Type 1 (SIB1 ) to adjust the transmission power in steps. The initial transmit power is chosen based on an estimation by the terminal of the downlink path loss which is based on a received signal strength of a synchronization signal block (SSB). Using the pathloss estimation, the terminal attempts to set the transmission power of the RACH preamble to align with the target RACH preamble reception power defined by the network. The techniqueassumes that the path loss experienced in the uplink is the same, or nearly the same, as the pathloss in the downlink. To estimate the pathloss (PL), the terminal compares the measured received signal strength of the SSB to the transmission power of the SSB provided to the terminal by a ss-PBCH-BlockPower parameter included in a System Information Block 1 (SIB1 ) broadcast message. The initial RACH preamble sequence transmission power (PPRACH) selected by the terminal is based on the estimated downlink path loss (PL) and the target RACH preamble reception power (Prach-rec) set by the network. The RACH preamble power (PPRACH) is dictated by the equation PPRACH = rn in(Pmax, Prach-rec + PL), where Pmax is the maximum transmission power of the terminal set by the network and based on capabilities of the terminal.

[0017] In conventional base station (gNB) configurations, the scheduler can allocate power for each resource element based on precise knowledge of the transmission power for each channel. ORAN architectures, however, lack direct control over these power settings which leads to the use of approximate power values in the SIB1 configuration. This approximation results in the terminal having an inaccurate estimate of the required RACH power. As a result, the terminal might transmit at a higher power than necessary during RACH attempts, wasting energy and potentially causing interference. Moreover, the imprecision in power calculation can increase the number of RACH attempts needed to achieve successful access, congesting the RACH channel with repeated attempts by the terminal and other terminals, thereby degrading the overall efficiency of connection setups in ORAN networks.

[0018] For the techniques discussed herein, however, the DU adjusts, or otherwise sets, the transmission power of the reference signal and sets power parameters, such as the ss-PBCH-BlockPower parameter, in the SIB1 based on power information related to signal reception at the RU. In some examples, the RU provides power information to the DU and the DU adjusts, or otherwise sets, the transmission power of the reference signal and sets power parameters, such as the ss-PBCH-BlockPower parameter, in the SIB1 based on the power information. As a result, the optimal transmit power for a terminal during the initial access phase can be determined for an ORAN system, enhancing the performance of initial access by reducing unnecessary powerexpenditure, minimizing interference, and streamlining the connection process to accommodate the dynamic nature of radio network environments.

[0019] In another example, the DU sets a power parameter in a first SIB1 broadcasted by a first RU based on power information related to reception at the first RU and sets the power parameter in a second SIB1 in a first SIB1 broadcasted by a second RU based on power information related to reception at the second RU. Accordingly, the SIB1 transmitted from RUs may have different power parameters due to a difference in conditions and / or difference in equipment at the RUs.

[0020] FIG. 1 A is a block diagram of an Open Radio Access Network (ORAN) system 100 for an example where a Radio Unit (RU) 102 sends power information 104 to a Distributed Unit (DU) 106 and the DU 106 adjusts power parameters based on the power information 104. The ORAN system 100 of FIG. 1A includes the RU 102, DU 106 and a Centralized Unit (CU) 108 where the RU 102 is connected to the DU 106 through fronthaul 110 with an open interface. The ORAN system 100 may include several DUs where each DU may be connected to more than one RU. The CU 108 may manage multiple DUs and is connected to the core network 112. Generally, the RU 102 performs radio transmission and reception functions to facilitate communication with one or more terminals 114 and the DU 106 performs higher layer functions, such as Medium Access Control (MAC) and Radio Link Control (RLC). In some situations, the DU may perform higher layer physical (PHY) layer function while the RU perform lower PHY layer operations. Several fronthaul split options have been proposed that provide different ways to divide the functions of the ORAN between the RU and the DU. For the examples herein, the DU 106 at least performs functions related to setting the transmission power level for SSB transmissions from the RU 102 and functions relating to generating SIB1 messages and, therefore, may use any split option consistent with such functionality. One suitable example is the widely used standardized split option 7- 2x where the precoding operation is performed at RU. A scheduler in the DU, however, control the precoder / beamforming weights at RU. The open structure and standard interface between the RU 102 and the DU 106 allows for the use of different equipment manufacturers providing an advantage to conventional systems using a base station(e.g., gNB) to perform the functions of both the RU and DU. Conventional ORAN systems, however, are limited in that the distributed architecture does not allow for the dynamic and precise power control typically employed by the integrated structure of a base station (gNB). When a terminal attempts to access the network using the Random Access Channel (RACH) procedure, for example, the terminal is provided a reference power which is only an estimate determined by the DU and where the estimate is used to set the transmission power of the initial transmission to the RU. For the examples herein, however, the RU 102 provides power information 104 to the DU 106 allowing the DU 106 to set the signal reference power and report the power level to the terminals in a system broadcast message broadcasted by the RU 102.

[0021] The power information 104 is determined by the RU 102 based on current conditions which may be related to the terminal transmission power capability and path loss. The power information provided to the DU 106 allows the DU 106 to determine the appropriate transmission power of the SS Block (SSB) 116 broadcasted from the RU 102. The power information 104 is related to the maximum allowed transmission power from the terminals which is typically referred to as Pmax. For the examples, the RU 102 sends power information indicative of a recommended ss-PBCH-BlockPower value to the DU. In some situations, the RU autonomously sends the power information while in other situations, the RU only sends the power information when requested by the DU. In one example, the RU measures the received power of signals transmitted by terminals and compares the measured power to the target power for signal reception to determine the power information.

[0022] After receiving the power information 104, the DU 106 sets, or otherwise adjusts, the Synchronization Signal Block (SS Block) (SSB) transmission power (reference signal power) based on the power information 104. The DU 106 also generates the SIB1 118, which will be broadcasted by the RU 102, to include the ss- PBCH-BlockPower value 120 indicative of the reference signal power of the SSB.

[0023] For the example, the terminal 114 engages in an initial access mechanism to connect to the network. The terminal 114 first acquires time and frequency synchronization, cell identification, and system information for the cell of the RU 102. The SSB / Physical Broadcast Channel (PBCH) 116 are broadcast from the RU 102,where the SSB includes a primary synchronization signal (PSS) and a secondary synchronization signal (SSS). A master information block (MIB) is broadcast within the PBCH. The MIB provides information that allows the terminal 114 to receive and decode the SIB1 118. The RU 102 broadcasts the SIB1 118 over the Physical Downlink Shared Channel (PDSCH) in accordance with the MIB parameters. The terminal 114 receives and decodes the SIB1 118 and retrieves the power parameters including the ss-PBCH- BlockPower value 120 indicative of the reference signal power. The terminal then determines the pathloss (PL) based on the measured RSRP of the SSB 116 and the reference signal power (transmission power of SSB) where PL - Reference Signal Power -RSRP, where the Reference Signal Power is obtained from the SIB1 parameter ss-PBCH-BlockPower and RSRP is the higher layer filtered Reference Signal Received Power. The received power parameters in the SIB1 also include a target received power (Prach-rec) for RACH preamble transmissions from the terminal to the RU. The target received power (Prach-rec) is the desired power level for the RACH preamble to be received at the RU. After determining the path loss (PL), the terminal determines the transmission power (PPRACH) for the RACH preamble which is equal to the minimum value between the maximum allowable transmission power of the terminal (Pmax) and the target received power adjusted for pathloss (e.g., PPRACH = rn in(Pmax, P rach-rec + PL)). The terminal transmits the RACH preamble 122 at the PPRACH power level in accordance with SIB1 parameters to start the RACH process to access the network. In accordance with conventional techniques, the terminal retransmits the RACH preamble with incrementally increasing transmission power in accordance with the powerRampingStep parameter in the SIB1 if the RACH preamble did not successfully initiate the RACH process.

[0024] FIG. 1 B is a block diagram of an ORAN system 100 for an example where the DU 106 sets a power parameter in SIB1s 118, 124 transmitted from different RUs 102, 126 to different values based on power information 104, 128 specific to each RU 102, 126. For the example of FIG. 1 B, therefore, the DU is connected to at least two RUs 102, 126 and has power information related to the reception of signals at each RU 102, 126. The power information may be sent dynamically to the DU from each RU in accordance with the techniques discussed with reference to FIG. 1A. In other situations,the power information may be stored at the DU at the time the RU is connected in the system 100. For example, the specific receiver sensitivity as reported by the manufacturer of the RU or as measured may be stored in memory and associated with the RU.

[0025] For the example of FIG. 1 B, the DU generates a first SIB1 118 with a power parameter 120 based on power information 104 related to reception at the first RU 102. The power parameter 120 for the example is the ss-PBCH-BlockPower parameter. The first SIB1 118 is sent to the first RU 102 and then broadcasted by the first RU to the terminals 114 in the service area of the first RU. The DU also generates a second SIB1 124 with a power parameter 130 based on power information 128 related to reception at the second RU 126. The power parameter 130 for the example is the ss-PBCH- BlockPower parameter. The second SIB1 124 is sent to the second RU 126 and then broadcasted by the second RU 126 to the terminals 132 in the service area of the second RU 126.

[0026] FIG. 2 is a block diagram of an example of a RU 102 connected to the DU 106 suitable for use in the example of FIG. 1A and FIG. 1 B. The RU 102 includes electronics 204, a transmitter 206, a receiver 208, and the antenna system 210, and a communication interface 212, as well as other electronics, hardware, and code. The RU 102 converts radio signals from the antenna into a digital signal for transmission over packet networks and handles digital front end (DFE) and the lower PHY layer operations and may perform digital beamforming in some situations.

[0027] The RU 102 is any fixed, mobile, or portable equipment that performs the functions described herein. The various functions and operations of the blocks described with reference to the RU 102 may be implemented in any number of devices, circuits, or elements. Two or more of the functional blocks may be integrated in a single device, and the functions described as performed in any single device may be implemented over several devices. The RU 102 may be a fixed device or apparatus that is installed at a particular location at the time of system deployment. Examples of such equipment include fixed radio transceivers and fixed transceiver stations. In some situations, the RU 102 may be mobile equipment that is temporarily installed at aparticular location. Some examples of such equipment include mobile transceiver stations that may include power generating equipment such as electric generators, solar panels, and / or batteries. Larger and heavier versions of such equipment may be transported by trailer. In still other situations, RU 102 may be a portable device that is not fixed to any particular location. The RU 102 may perform downlink functions, including for example, lower PHY layer tasks, such as the Beamforming, IFFT, adding CP, DAC and up-conversion. The RU 102 may perform uplink functions, including for example, down-conversion, ADC, CP removal and FFT processing.

[0028] The electronics 204 include any combination of hardware, software, and / or firmware for communicating with and controlling other RU components to execute the functions described herein as well as facilitating the overall functionality of the RU 102. The electronics 204, therefore, cooperatively operate with other RU 102 components to initiate tasks and perform the operations and functions of the RU 102. An example of suitable electronics 204 includes code running on a microprocessor or processor arrangement connected to memory 214. The transmitter 206 includes electronics configured to transmit wireless signals. In some situations, the transmitter 206 may include multiple transmitters. The receiver 208 includes electronics configured to receive wireless signals. In some situations, the receiver 208 may include multiple receivers. The receiver 208 may receive signals through multiple antennas or through a selected antenna of the antenna system 210. The antenna system 210 may include separate transmit and receive antennas in some situations.

[0029] The transmitter 206 and receiver 208 in the example of FIG. 2 perform radio frequency (RF) processing including modulation and demodulation. The receiver 208, therefore, may include components such as low noise amplifiers (LNAs) and filters. The transmitter 206 may include filters and amplifiers. Other components may include isolators, matching circuits, and other RF components. These components in combination or cooperation with other components perform the base station functions. The required components may depend on the particular functionality required by the base station 200.

[0030] The transmitter 206 includes a modulator (not shown), and the receiver 208 includes a demodulator (not shown). The modulator modulates the signals to betransmitted as part of the downlink signals and can apply any one of a plurality of modulation orders. The demodulator demodulates any uplink signals received at the base station 200 in accordance with one of a plurality of modulation orders. The electronics 204 in conjunction with the transmitter 206 apply a precoder matrix to signals transmitted through the multiple antennas 210.

[0031] The RU 102 includes a communication interface 212 for communicating with the DU 106. The communication interface 212 is connected to the fronthaul 110. In some situations, the link between RU and DU may include at least some wireless portions. The communication interface 212, therefore, may include wireless communication functionality and may utilize some of the components of the transmitter 206 and / or receiver 208.

[0032] The electronics 204, in conjunction with the receiver 208, measure and evaluate signals transmitted by terminals (UE devices). The electronics 204 and the receiver 208, therefore, can receive, measure, and evaluate uplink signals including reference signals transmitted by terminals. Signal measurements and evaluations can be stored in a memory 214 and used to determine received power levels. The electronics 204, in conjunction with the transmitter 206 and antenna system 210, process outgoing signals to precode signals transmitted to terminals (UE devices).

[0033] The DU 106 performs processing for the lower layers of the protocol stack, including Radio Link Control (RLC) and Medium Access Control (MAC), as well as some higher layer PHY layer tasks. The DU 106 manages the data link between the terminal and the network by handling real-time radio signal processing and is typically located close to the RU 102. The DU 106 is controlled by the Central Unit (CU) 108 to ensure efficient data transmission and reduced latency. The DU 106 includes a communication interface 215 that facilitates communication with the RU 102 over the fronthaul 110.

[0034] The DU 106 is any fixed, mobile, or portable equipment that performs the functions described herein. The various functions and operations of the blocks described with reference to the DU 106 may be implemented in any number of devices, circuits, or elements. Two or more of the functional blocks may be integrated in a singledevice, and the functions described as performed in any single device may be implemented over several devices. The DU 106 may be a fixed device or apparatus that is installed at a particular location at the time of system deployment. In some situations, the DU 106 may be mobile equipment that is temporarily installed at a particular location.

[0035] The electronics 216 include any combination of hardware, software, and / or firmware for communicating with and controlling other DU components to execute the functions described herein as well as facilitating the overall functionality of the DU 106. The electronics 216, therefore, cooperatively operate with other DU 106 components to initiate tasks and perform the operations and functions of the DU 106. An example of suitable electronics 216 includes code running on a microprocessor or processor arrangement connected to memory 218. The

[0036] The DU 106 includes a communication interface 220 for communicating with the CU 108. The communication interface 220 is connected to midhaul to the CU 108.In some situations, a single communication interface can perform the functions of the communication interface 212 and the communication interface 220.

[0037] FIG. 3 is a block diagram of an example of a UE device 300 suitable for use as a terminal device 114. In some examples, the UE device 300 is any wireless communication device such as a mobile phone, a transceiver modem, a personal digital assistant (PDA), a tablet, or a smartphone. In other examples, the UE device 300 is a machine type communication (MTC) communication device or Internet-of-Things (loT) device. The UE device 300, therefore is any fixed, mobile, or portable equipment that performs the functions described herein. The various functions and operations of the blocks described with reference to UE device 300 may be implemented in any number of devices, circuits, or elements. Two or more of the functional blocks may be integrated in a single device, and the functions described as performed in any single device may be implemented over several devices.

[0038] The UE device 300 includes at least electronics 302, a transmitter 304 and a receiver 306. The electronics 302 include any combination of hardware, software, and / or firmware for communicating with and controlling other UE device components toexecute the functions described herein as well as facilitating the overall functionality of a communication device. The electronics 302, therefore, cooperatively operate with other UE device components to initiate tasks and perform the operations and functions of the UE device 300. An example of suitable electronics 302 includes code running on a microprocessor or processor arrangement connected to memory 310. The transmitter 304 includes electronics configured to transmit wireless signals. In some situations, the transmitter 304 may include multiple transmitters. The receiver 306 includes electronics configured to receive wireless signals. In some situations, the receiver 306 may include multiple receivers. The receiver 306 and transmitter 304 receive and transmit signals, respectively, through antenna 308. The antenna 308 may include separate transmit and receive antennas. In some circumstances, the antenna 308 may include multiple transmit and receive antennas.

[0039] The transmitter 304 and receiver 306 in the example of FIG. 3 perform radio frequency (RF) processing including modulation and demodulation. The receiver 306, therefore, may include components such as low noise amplifiers (LNAs) and filters. The transmitter 304 may include filters and amplifiers. Other components may include isolators, matching circuits, and other RF components. These components in combination or cooperation with other components perform the communication device functions. The required components may depend on the particular functionality required by the communication device.

[0040] The transmitter 304 includes a modulator (not shown), and the receiver 306 includes a demodulator (not shown). The modulator can apply any one of a plurality of modulation orders to modulate the signals to be transmitted as part of the uplink signals. The demodulator demodulates the downlink signals in accordance with one of a plurality of modulation orders.

[0041] The UE device 300 is capable of transmitting and receiving sidelink signals to and from other UE devices as well as communicating with base stations. The electronics 302, in conjunction with the receiver 306, measure an evaluate signals transmitted by other devices, such as base stations and UE devices. The electronics 302 and the receiver 306, therefore, can receive, measure, and evaluate downlinkreference signals transmitted by a base station. Signal measurements and evaluations can be stored in the memory 310.

[0042] FIG. 4 is a messaging diagram for an example where the RU provides power information to the DU 106. One or more of the events and / or transmissions may be omitted, combined, performed in parallel, or performed in a different order than that described herein or shown in FIG. 4. In still further examples, additional events and / or transmissions may be added that are not explicitly described in connection with the example discussed with reference to FIG. 4.

[0043] At event 402, the RU 102 determines the power information. The RU 102 monitors network conditions and transmission power levels of neighboring cells and determines the power information. The RU 102 may also monitor environmental conditions affecting signal transmission power and dynamically update the power information based on those conditions. The RU 102 may determine the received power levels of signals transmitted by terminals and base the power information on the received power levels and the target power levels. In some situations, the power information is based on, or includes, parameters indicative of thermal noise and background interference caused by other terminal devices (intercell and intracell) at the RU receiver. The power information may also include parameters impacting receiver sensitivity such as receiver and antenna design implementation. In one example, the power information is a recommended reference signal power for transmission of a synchronization signal block (SSB). The power information, therefore, may be a recommended ss-PBCH-BlockPower value indicative of the recommended reference signal power.

[0044] At transmission 404, the RU 102 sends the power information over the fronthaul 110 to the DU 106.

[0045] At event 406, the DU 106 adjusts, or otherwise sets, the reference power level based on the power information received from the RU 102.

[0046] At transmission 408, the DU sends the SSB with the PBCH including the MIB to the RU 102 for broadcasting the SSB / PBCH and transmission 410. Terminals in the service area of the RU 102 can receive the broadcasted message 410. The DU 106, therefore, broadcasts the SSB / PBCH with the MIB via the RU 102.

[0047] At event 412, the terminal 114 receives and decodes the MIB and measures the received power level of the SSB. In accordance with conventional techniques, the terminal 114 receives the SSB, PBCH and MIB which provides the required information for the terminal to receive the SIB1 .

[0048] At event 414, the DU 106 generates the SIB1 that includes power parameters based on the power information received from the RU 102. For the example, the SIB1 , includes an ss-PBCH-BlockPower value indicative of the transmission power at which the SSB is broadcasted.

[0049] At transmission 416, the SIB1 is broadcasted via the RU 102. The DU 106 sends the SIB1 over the fronthaul to the RU 102 which broadcasts the SIB1 within the cell of the RU 102 at transmission 418.

[0050] At event 420, the terminal determines the path loss (PL) and the transmission power (PPRACH) of the RACH preamble that will be transmitted. The terminal 114 uses the information in MIB and PBCH to receive the SIB1. The power parameters in the SIB1 are used to determine the (PPRACH). The terminal calculates the path loss based on the difference of the ss-PBCH-BlockPower value and measured RSRP of the SSB. The path loss is added to the target received power value (Prach-rec) provided by the network to determine the required transmission power of the RACH preamble. The transmission power (PPRACH) of the RACH preamble is then determined from PPRACH = rnin(Pmax, Prach- rec + PL), where Pmax is the maximum transmission power of the terminal set by the network and based on capabilities of the terminal.

[0051] At transmission 422, the terminal 114 transmits the RACH preamble at the transmission power (PPRACH). The RU 102 receives and forwards the RACH preamble to the DU 106. The terminal 114 and the DU 106 perform the RACH procedure via the RU 102 at event 424.

[0052] FIG. 5A is a flowchart of an example of power management performed at an RU of an ORAN system for initial network access transmissions from terminals. Accordingly, the method can be performed by the RU 102 discussed herein. The method may be performed using any of several techniques involving any combination of software, hardware, and firmware. For example, software code running on electronicsincluding a processor, computer or other processor arrangement within the RU 102 may facilitate the generation, formatting, reception, and transmission of signals and messages as well as facilitating measurements, evaluations and determinations. One or more of the steps may be omitted, combined, performed in parallel, or performed in a different order than that described herein or shown in FIG. 5A. In still further examples, additional steps may be added that are not explicitly described in connection with the example discussed with reference to FIG. 5A.

[0053] At step 502, the RU 102 determines the power information. The RU monitors network conditions and transmission power levels of neighboring cells and determines the power information. The RU may also monitor environmental conditions affecting signal transmission power dynamically update the power information based on those conditions. The RU 102 may determine the received power levels of signals transmitted by terminals and base the power information on the received power levels and the target power levels. The power information, therefore, may be a recommended ss- PBCH-BlockPower value indicative of the recommended reference signal power.

[0054] At step 504, the RU 102 sends the power information over the fronthaul 110 to the DU 106.

[0055] At step 506, the RU broadcasts the SSB and PBCH including the MIB within the cell provided by the RU 102. The SSB / PBCH is received from the DU 106 and is broadcasted at the reference power level determined by the DU 106.

[0056] At step 508, the RU 102 broadcasts the SIB1 . The SIB1 is received from the DU 106 over the fronthaul 110 and includes power parameters based on the power information received from the RU 102. For the example, the SIB 1 , includes an ss- PBCH-BlockPower value indicative of the transmission power at which the SSB is broadcasted.

[0057] At step 510, the RU 102 receives the RACH preamble transmitted by the terminal at the transmission power (PPRACH). The RU 102 forwards the RACH preamble to the DU 106. At step 512, the RU 106 facilitates the RACH process between the terminal 114 and the DU 106.

[0058] FIG. 5B is a flowchart of an example of performing power information determination and reporting at an RU where the RU monitors conditions and reports thepower information to the DU in response to a power information request received from the DU 106. Accordingly, the method of FIG. 5B is an example of a method of performing steps 502 and 504 of FIG. 5A.

[0059] At step 520, the RU monitors network conditions and power transmissions. The RU also monitors environmental conditions affecting signal transmission power.

[0060] At step 522, the RU determines if the power information has changed based on the latest conditions. For example, if a recommended reference signal power has changed based on the measured conditions or network conditions, the RU determines the power information has changed. If there is no change in power information, the method returns to step 520 to continue monitoring conditions. Otherwise, the method proceeds to step 524.

[0061] At step 524, the RU determines whether a power information request has been received from the DU. If no request has been received, the method returns to step 520. Otherwise, the method proceeds to step 526 where the RU sends the updated power information to the DU.

[0062] In other examples, step 524 can be omitted and the RU reports updated power information to the DU when the power information changes. In still other examples, the power information may be reported in response to a request from the DU even if no change in power information has been detected.

[0063] FIG. 6 is a flow chart of an example of power management performed at a DU of an ORAN system for initial network access transmissions from terminals.Accordingly, the method can be performed by the DU 106 discussed herein. The method may be performed using any of several techniques involving any combination of software, hardware, and firmware. For example, software code running on electronics including a processor, computer or other processor arrangement within the DU 106 may facilitate the generation, formatting, reception, and transmission of signals and messages as well as facilitating measurements, evaluations and determinations. One or more of the steps may be omitted, combined, performed in parallel, or performed in a different order than that described herein or shown in FIG. 6. In still further examples, additional steps may be added that are not explicitly described in connection with the example discussed with reference to FIG. 6.

[0064] At step 602, the DU 106 receives power information from the RU 102. The power information, therefore, may be a recommended ss-PBCH-BlockPower value indicative of the recommended reference signal power.

[0065] At step 604, the DU 106 adjusts, or otherwise sets, the reference power level based on the power information received from the RU 102. For the example, the DU 106 sets the transmission power level of the SSB that will be broadcast from the RU 102.

[0066] At step 606, the DU 106 broadcasts the SSN / PBCH with the MIB via the RU. The DU sends the SSB with the PBCH including the MIB to the RU 102 over the front haul 110 and the RU 102 broadcasts the SSB / PBCH at the reference power level.

[0067] At event 608, the DU 106 generates the SIB1 that includes power parameters based on the power information received from the RU 102. For the example, the SIB1 , includes an ss-PBCH-BlockPower value indicative of the transmission power at which the SSB is broadcasted.

[0068] At step 610, the SIB1 is broadcasted via the RU 102. The DU 106 sends the SIB1 over the fronthaul to the RU 102 which broadcasts the SIB1 within the cell of the RU 102.

[0069] At step 612, the DU receives a RACH preamble via the RU. The RU forwards the RACH preamble transmitted by the terminal 114 at the RACH preamble at the transmission power (PPRACH).

[0070] At step 614, the terminal 114 and the DU 106 perform the RACH procedure via the RU 102.

[0071] To clearly illustrate this interchangeability of hardware, firmware and software, various illustrative components, blocks, modules, circuits, and steps have been described above generally in terms of their functionality. Whether such functionality is implemented as hardware, firmware or software, or a combination of these techniques, depends upon the particular application and design constraints imposed on the overall system. The described functionality may be implemented in various ways for each particular application, but such implementation decisions do not cause a departure from the scope of the present disclosure. In accordance with various embodiments, aprocessor, device, component, circuit, structure, machine, module, etc. can be configured to perform one or more of the functions described herein. The term "configured to" or "configured for" as used herein with respect to a specified operation or function refers to processors, devices, components, circuits, electronics, and equipment that are physically constructed, programmed, instructed and / or arranged to perform the specified operation or function. Furthermore, the various illustrative logical blocks, modules, devices, components and circuits described herein can be implemented within or performed by an integrated circuit (IC) that can include a general-purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), other electronics or combinations thereof. (ASIC), a field programmable gate array (FPGA) or other programmable logic device, or any combination thereof. The logical blocks, electronics, and circuits can further include antennas and / or transceivers to communicate with various components within the network or within the device. A general-purpose processor can be a microprocessor, but in the alternative, the processor can be any conventional processor, controller, or state machine. A processor can also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other suitable configuration to perform the functions described herein.

[0072] When implemented in software, the functions can be stored as one or more instructions or code on a computer-readable medium. Thus, the steps of a method or algorithm disclosed herein can be implemented as software stored on a computer- readable medium. Computer readable media includes both computer storage media and communication media including any medium that can be enabled to transfer a computer program or code from one place to another. A storage media can be any available media that can be accessed by a computer. By way of example, and not limitation, such computer-readable media can include RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to store desired program code in the form of instructions or data structures and that can be accessed by a computer.

[0073] Therefore, the methods and apparatus of this invention may take the form, at least partially, of program logic or program code (i.e., instructions) embodied in tangible media, such as a machine-readable storage medium. When the program code is loaded into and executed by a machine, such as a computer, the machine becomes an apparatus for practicing the invention. The methods and apparatus of the present invention may also be embodied in the form of program code that is transmitted over some transmission medium, such as over electrical wiring or cabling, through fiber optics, or via any other form of transmission. When the program code is received and loaded into and executed by a machine, such as a computer, the machine becomes an apparatus for practicing the invention. When implemented on a general-purpose processor, the program code combines with the processor to provide a unique apparatus that operates analogously to specific logic circuits.

[0074] Additionally, memory or other storage, as well as communication components, may be employed in embodiments of the present disclosure. It will be appreciated that, for clarity purposes, the above description has described embodiments of the present disclosure with reference to different functional units and processors. However, it will be apparent that any suitable distribution of functionality between different functional units, processing logic elements or domains may be used without detracting from the present disclosure. For example, functionality illustrated to be performed by separate processing logic elements, or controllers, may be performed by the same processing logic element, or controller. Therefore, references to specific functional units are only references to a suitable means for providing the described functionality, rather than indicative of a strict logical or physical structure or organization.

[0075] Clearly, other embodiments and modifications of this invention will occur readily to those of ordinary skill in the art in view of these teachings. The above description is illustrative and not restrictive. This invention is to be limited only by the following claims, which include all such embodiments and modifications when viewed in conjunction with the above specification and accompanying drawings. The scope of the invention should, therefore, be determined not with reference to the above description, but instead should be determined with reference to the appended claims along with their full scope of equivalents.

Claims

CLAIMS1 . A method comprising: determining, at a Distributed Unit (DU) of a system, a power parameter value based on power information related to signal reception at a Radio Unit (RU), the RU connected to the DU through a fronthaul; generating a System Information Block Type 1 (SIB1 ) comprising the power parameter value; broadcasting the SIB1 via the RU; receiving a Random Access Channel (RACH) preamble sequence transmission from a terminal via the RU, the RACH preamble transmission transmitted from the terminal at a power level at least partially based on the power parameter.

2. The method of claim 1 , wherein the system is an Open Radio Access Network (ORAN) system and the power information is received from the RU over the fronthaul.

3. The method of claim 1 , wherein the power information is stored in memory at the DU.

4. The method of claim 3, further comprising: determining, at the DU, another power parameter value based on other power information related to signal reception at another RU; generating another SIB1 comprising the another power parameter value; and broadcasting the another SIB1 via the another RU.

5. The method of claim 4, further comprising: receiving another preamble sequence transmission from another terminal via the another RU, the another RACH preamble transmission transmitted from the another terminal at another power level at least partially based on the another power parameter.

6. The method of claim 1 , wherein the power information comprises a recommended reference signal power for transmission of a synchronization signal block (SSB) via the RU, the power parameter value comprising an ss-PBCH-BlockPower value indicative of the recommended reference signal power.

7. The method of claim 6, further comprising broadcasting the SSB via the RU at the recommended reference signal power.

8. The method of claim 1 , wherein the power information is autonomously generated and reported by the RU.

9. The method of claim 1 , further comprising: transmitting a power information request to the RU, the power information generated and reported by the RU in response to the power information request.

10. The method of claim 1 , further comprising dynamically adjusting the power parameters of the SIB1 in response to changes in network load and interference patterns.

11. A method comprising: determining, at a Radio Unit (RU) of an Open Radio Access Networks (ORAN) system, power information; transmitting the power information to a Distributed Unit (DU) of the ORAN; receiving, at the RU, a System Information Block Type 1 (SIB1 ) comprising a power parameter value based on the power information; broadcasting the SIB1 from the RU; receiving a Random Access Channel (RACH) preamble sequence transmission from a terminal, the RACH preamble transmission transmitted from the terminal at a power level at least partially based on the power parameter value.

12. The method of claim 11 , wherein the power information is based on current network conditions and power settings of neighboring cells.

13. The method of claim 11 , wherein the power information is dynamically updated by the RU based on a monitoring of environmental conditions affecting signal transmission power, the transmitting comprising transmitting the power information when updated.

14. The method of claim 11 , wherein the power information comprises a recommended reference signal power for transmission of a synchronization signal block (SSB) via the Rll, the power parameter value comprising an ss-PBCH-BlockPower value indicative of the recommended reference signal power.

15. The method of claim 1 , further comprising broadcasting the SSB via the Rll at the recommended reference signal power.

16. The method of claim 11 , wherein the power information is autonomously generated and reported by the RU.

17. The method of claim 11 , further comprising: receiving a power information request from the DU, the transmitting in response to the power information request.

18. The method of claim 11 , further comprising dynamically adjusting the power parameters of the SIB1 in response to changes in network load and interference patterns.

19. A Radio Unit (RU) for operating in an Open Radio Access Networks (ORAN) system, the RU comprising: electronics configured to determine power information;a communication interface configured to transmit the power information to a Distributed Unit (DU) of the ORAN, the communication interface configured to receive, from the DU, a System Information Block Type 1 (SIB1 ) comprising a power parameter value based on the power information; a transmitted configured to broadcast the SIB1 from the RU; a receiver configured to receive a Random Access Channel (RACH) preamble sequence transmission from a terminal, the RACH preamble transmission transmitted from the terminal at a power level at least partially based on the power parameter value.

20. The RU of claim 19, wherein the power information comprises a recommended reference signal power for transmission of a synchronization signal block (SSB), the power parameter value comprising an ss-PBCH-BlockPower value indicative of the recommended reference signal power, the transmitter configured to transmit the SSB at the recommended reference signal power.

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