What is the difference between referenceSignalPower in sib 2 and system settings?

This reference signal strength is not set, it is in the measurement report. Uplink power control is very important in wireless systems. Through uplink power control, the mobile station in the cell can not only ensure the quality of uplink data, but also reduce the interference to the system and other users as much as possible, and prolong the service life of the mobile station battery. In LTE, uplink data between different users in the same cell is designed to be orthogonal to each other. Therefore, compared with WCDMA, the management of uplink interference in a cell is much easier, and the uplink power control in LTE is slower than the fast power control in WCDMA. Through power control, LTE is mainly used to adapt uplink transmission to different wireless transmission environments, including path loss, shadow, fast fading, interference from other users within and between cells, etc. In LTE, for the same MCS (modulation and coding scheme), the power spectral density (PSD, that is, power per bandwidth) of different UEs arriving at the eNodeB is approximately equal. ENodeB allocates different transmission bandwidth and modulation coding mechanism MCS for different UEs, so that UEs under different conditions can obtain corresponding different uplink transmission rates. The objects of LTE power control include PUCCH, PUSCH, SRS, etc. Although the data rates and importance of these uplink signals are different, their specific power control methods and parameters are also different. But the principle is basically the same, which can be summarized as follows: (The power control of uplink access, such as RA preamble and RA Msg3, will be different and will be described in the corresponding access section): the power spectral density of UE transmission (i.e. power per RB) = open-loop industrial control point+dynamic power offset. Where the open-loop industrial control point = nominal power P0+ open-loop loss compensation α×(PL). The nominal power P0 is divided into two parts: the cell nominal power and the UE-specific nominal power. The eNodeB semi-statically sets the nominal powers P0_PUSCH and P0_PUCCH for all UE in the cell, and broadcasts these values through SIB2 system messages (P0-nominalpusch, P0-nominalpucch); The range of P0_PUSCH is-126dBm to ++24 dBm (all refer to each RB). The range of P0_PUCCH is-126 dBm to-96 dBm. In addition, each UE may also have a UE-specific nominal power offset, which is sent to the UE through dedicated RRC signaling (P0-UE-PUSCH, P0-UE-PUCCH). The unit of P0_UE_PUSCH and P0 _ UE _ PUSCH is dB, and the values are between -8 and +7, which are the offsets of different UEs to the system nominal powers P0_PUSCH and P0 _ UE _ PUSCH. It should be noted that the value of P0_PUSCH used for semi-static scheduled uplink transmission is also different (SPs-configul: P0-nominalpusch-persistent). Semi-static scheduling is applied to VoIP and so on. Generally, it is desirable to minimize the system overhead caused by signaling transmission, including retransmission of the required PDCCH signaling. Therefore, for SPS semi-static uplink transmission, higher transmission power can be applied to achieve a better BLER (Block Error Rate) operating point. Open-loop path loss compensation PL downlink path loss estimation based on UE. The UE estimates the path loss by measuring the downlink reference signal RSRP and subtracting it from the known RS signal power. The original transmission power of RS signal is broadcast in SIB2 in PDSCH-Config common: reference signal power, ranging from-60dBm to 50dBm. In order to counteract the influence of fast fading, UE usually averages the downlink RSRP within a time window. The length of time window is generally between 100ms and 500 ms. For PUSCH and SRS, eNodeB determines the weight of path loss in UE uplink power control through parameter α. For example, for the UE at the edge of the cell, if its transmission power is too high, it will cause interference to other cells, thus reducing the capacity of the whole system. This can be controlled by alpha. α is semi-statically set in the system message (UplinkPowerControlCommon: alpha). For PUCH, because different PUCH users are code division multiplexing, the value of α is 1, which can better control the interference between different PUCH users. Dynamic power offset includes two parts, power adjustment △TF based on MCS and closed-loop power control. Power adjustment based on MCS can make UE dynamically adjust the corresponding transmission power spectral density according to the selected MCS. The MCS of the UE is scheduled by the eNodeB. By setting the transmission MCS of the UE, the transmission power density spectrum of the UE can be quickly adjusted to achieve the effect similar to fast power control. The specific formula of △TF is in section 5. 1. 1 of 36.2 13. The eNodeB can also turn off or turn on MCS-based power adjustment on a per-UE basis, and this can be achieved through dedicated RRC signaling (enabling incremental MCS). The MCS-based power adjustment in PUCCH is as follows: LTE system will define the power offset (uplink) relative to format 1a for each PUCCH format.