Abstract This paper introduces a scheme for collecting and reporting physical layer measurement values. First, a physical layer measurement model is given, then the selection of measurement parameters is explained, and finally, the entire framework and process for collecting and reporting physical layer measurement results in radio resource management and operation maintenance are described in detail. 1. Introduction Measurement is an important function of the TD-SCDMA system. The measurement results reported by the physical layer can be used by the radio resource control sublayer to trigger events such as cell selection/reselection and handover, and can also be used by the operation and maintenance part of the system to observe the system's operating status. The system's measurement can be described by the measurement model shown in Figure 1. Point A is the entry point for various measurement samples. The physical layer collects the measurement samples and generates various measurement parameters, which are output from point B. The measurement parameters output from point B are filtered by the physical layer to extract the required measurement parameters, which are then output from point C. Layer 3 filtering processes and filters the measurement data from the lower layer according to the requirements of the peer layer, and the results are output from point D. The reporting criterion evaluator compares the value from point D with some threshold values ​​(point D′) to determine whether to send the measurement report through the Uu port or the Iub port. If the conditions are met, such as the timeout period (periodic measurement report) or the occurrence of a trigger event (event-triggered measurement report), the evaluator constructs a measurement report according to the format required by the peer layer entity, based on the protocol requirements, and outputs it from point E. Point E can be regarded as the Uu interface (UE-NodeB) or the Iub interface (NodeB-RNC). The measurement values ​​reported by the TD-SCDMA physical layer in this scheme are output from point E to the physical layer measurement interface. [align=center]Figure 1 Measurement Model[/align][align=left] 2. Selection of Measurement Parameters Referring to the 3GPP TS25.225 protocol, measurement parameters can be divided into UE (User Equipment) side measurement parameters and network side measurement parameters. 2.1 Selection of UE Side Measurement Parameters The UE side mainly measures the following parameters: ● Interference signal code power (ISCP) in a given time slot, which is equal to the power of all training codes (midamble) received in a given time slot minus the useful signal code power, used to measure the interference of other user signals to this user signal in the time slot. ● P-CCPCH Received Signal Code Power (P-CCPCH RSCP): The signal code power received on the P-CCPCH of the local cell or a neighboring cell. ● UTRAN Carrier Frequency Received Signal Strength Power (RSSI): The broadband power measured on a given frequency and time slot. ● Signal-to-Interference Ratio (SIR): SIR = RSCP / Interference × SF, where RSCP is the received signal code power on the configured channel, Interference is interference added to the signal that cannot be eliminated by the receiver, and SF is the spreading factor used. ● Transmission Channel Block Error Rate (BLER): The statistical measure of bad data blocks received per unit time on a given transmission channel. ● UE Transmit Power: The transmit power of the UE on a given carrier frequency and time slot. ● SFN-CFN Observation Time Difference: The time difference between the system frame number of a given neighboring cell and the connection frame number of the UE. ●SFN-SFN observation time difference, i.e., the timing difference of received frames measured by the UE from two UTRAN cells (serving cell and target cell). ●Timing advance (TADV), TADV=TRX-TTX, where TRX is the start time of the uplink time slot calculated by the UE from the received signal based on a certain downlink time slot. TTX is the start point of the time slot actually used by the UE in the same uplink time slot. 2.2 Analysis of cell measurement parameters The selected cell measurement parameters include: ●RSCP (received signal code power), the power of a certain signal code received on physical channels such as DPCH, PRACH or PUSCH. ●ISCP. ●Total received broadband power, i.e., the received power (including signal and noise) within the bandwidth of the pulse shaping filter. [/align][align=left] 3. Measurement acquisition and reporting structure framework The acquisition and reporting of measurement values ​​is completed by two parts: radio resource management (RRM) and operation and maintenance (OAM), and its framework is shown in Figure 2. Figure 2. Measurement Acquisition and Reporting Framework[/align][align=left] 3.1 OAM Section The measurement value acquisition and reporting function of the OAM section is jointly completed by three parts: the background control Server module, the front-end main control Manager module, and the front-end execution Agent module, through a message mechanism. OAM is responsible for initiating measurement tasks for UEs or cells, acquiring measurement values ​​from RRM, and displaying, storing, and maintaining the measurement results. The Server module is responsible for setting up, initiating, and stopping measurement tasks, providing a visual user interface, and receiving, displaying, storing, and maintaining measurement results. The Manager module is a subtask residing on the Operation Maintenance Processor (OMP) board. It is responsible for forwarding measurement task requests from the Server to the corresponding Agent process and forwarding measurement request responses from the Agent to the Server. The Agent module is a subtask residing on each Call Main Processor (CMP) board. It is responsible for receiving measurement task requests forwarded by the Manager and reporting the measurement results reported by the RRM to the Manager. 3.2 The RRM part is shown in Figure 2. The RRM part involved in the measurement is also a subtask residing on the CMP board. The RRM is divided into an algorithm module and a measurement module. The algorithm module (AM) implements the RRM's functions such as call admission control, dynamic channel allocation, handover control, load congestion control, power control, cell selection and reselection, and radio bearer control; the measurement control module (MCM) implements the RRM's measurement functions. The RRM is responsible for initiating measurements on the Uu or Iub interface. After the interface reports the measurement report, it processes the collected measurement reports and combines them into UE measurement information or cell measurement information format and reports them to the OAM. 4. Measurement Value Acquisition and Reporting Process The measurement value acquisition and reporting process is shown in Figure 3. The scheme designs two processing methods (physical layer periodic reporting and event-triggered measurement reporting). In actual systems, these two methods are generally used in combination. Figure 3 Measurement Value Acquisition and Processing Process The physical layer periodic reporting method involves the OAM initiating a measurement request. The RRM processes requests and initiates measurements, with the physical layer periodically reporting the data. Event-triggered measurement reporting does not involve OAM measurement request initiation; instead, the physical layer proactively reports the measurement report to the RRM's measurement module when a trigger event occurs. 4.1 RRM Measurement Value Acquisition and Reporting 4.1.1 RRM Initiation of Measurement The RRM measurement initiation process is shown in Figure 4, where AM represents the algorithm module and MCM represents the measurement module. [align=center] Figure 4 RRM Measurement Initiation Process[/align][align=left] Each algorithm module sends a measurement request message (MEAS_REQ) to the measurement module according to its needs, starts a timer to wait for a response, and the measurement module receives the MEAS_REQ within the timer's set time and immediately sends a measurement request message response (MEAS_ACK). If no MEAS_ACK is received within the timer's set time, the measurement request message is discarded and retransmitted. The measurement module parses the MEAS_REQ message and determines whether it is a Uu port measurement or an Iub port measurement based on the measurement algorithm. Based on the parsed information, it searches the database for the corresponding field information. If the corresponding measurement field is set to allowed, the following steps can be performed. The measurement module searches the database to obtain the measurement scheme and measurement parameter configuration, and combines them with the measurement request message sent by the algorithm module to form a measurement control message (MEAS_CTR), which is then sent to the corresponding measurement process (Uu or Iub measurement process) to initiate the measurement. 4.1.2 Physical Layer Measurement Reporting to RRM The reporting of measurement results can be periodic or triggered by specific events. The reporting process (see Figure 5) is as follows: [/align][align=center]Figure 5 RRM Measurement Value Reporting Process[/align] ● After receiving the measurement control message (MEAS_CTR), the Uu or Iub interface measurement process organizes the measurement report into a measurement report message (MEAS_REPORT) and sends it to the RRM measurement module when the timer expires (periodic measurement report) or the trigger event occurs (event-triggered measurement report). The measurement report includes the UE part and the cell part. ● Upon receiving the MEAS_REPORT, the measurement module first decodes it according to the predefined interface data structure. ● The measurement module then searches for the corresponding algorithm module according to the different measurement report types. ● Each corresponding algorithm module performs event triggering processing based on the decoded MEAS_RE_PORT. In the UE part, this includes: allocating or reconfiguring a dedicated physical channel for the user, reconfiguration, cell handover, etc.; in the cell part, this includes: judging changes in cell load status, judging changes in code table information, and accepting/releasing a new user. ● Each algorithm module then calls the interface function of the Agent in OAM to output the required measurement information. 4.2 OAM Measurement Acquisition and Reporting The OAM acquisition initiation process is as follows: The Server sends a measurement task message MEAS_REQ to the Manager process on the OMP board. The Manager process queries the database based on the task message, finds the corresponding CMP board, and forwards it to the Agent process on that board. After receiving the measurement task message, the Agent process judges whether the message is valid. If valid, it returns a success response MEAS_ACK to the Manager process; if invalid, it returns a parameter error response MEAS_ACK to the Manager process. The Manager process forwards the response MEAS_ACK to the Server, as shown in Figure 6. Measurement value reporting is implemented by the RRM calling the functions provided by OAM. The Agent reads the UE or cell measurement information reported by the RRM and sends it to the Manager. After receiving the measurement information data from the RRM, the Manager adds time information and sends it to the Server, as shown in Figure 7. [align=center]Figure 7 OAM Reporting Process[/align] 5. Conclusion The above-mentioned TD-SCDMA measurement acquisition and reporting scheme has been practically verified. It is feasible and has high processing efficiency. The advantages of this scheme are mainly: ● The measurement acquisition and reporting scheme is divided into an OAM module and an RRM module, with a clear structure and easy implementation. At the same time, the RRM is divided into a measurement module and an algorithm module. After the measurement value is reported, it is processed and distributed to each algorithm module. Each algorithm module can then trigger corresponding events. The coupling between modules is small, which facilitates functional expansion. ● The modules of the framework interact with each other through request-response message passing. By reasonably designing the interaction data structure and communication process, the process can be simplified. ● In the OAM part, dividing the front-end processing flow into the Manager central control part and the Agent execution part is an innovation. The task is divided into various sub-tasks residing on the CMP board by the central control, which facilitates the control of different sub-tasks residing on the CMP board. Meanwhile, this structure is easily expandable; adding subtasks only requires adding CMP boards and interface functions. It has no impact on other CMP boards or the subtasks residing on them. ● OAM and RRM obtain measurement results through interface function calls residing on the CMP board. This is a supplement to the request-response message passing communication mechanism and also an innovation. This approach allows each algorithm module to flexibly send measurement results to OAM when an event is triggered, rather than simply processing them uniformly, thus shielding the processing difficulties caused by the vastly different processing mechanisms of algorithm modules. It eliminates the need to define unified interface data and message body structures, instead using a one-to-one processing approach, which facilitates algorithm optimization. Editor: He Shiping