Sounding Reference Signal 5G (New Radio)

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Introduction to Sounding Reference Signal 5G NR

Sounding Reference Signal (SRS) is a signal transmitted on the uplink channel in 5G. SRS can be used to estimate channel state information and eigenmodes of the radio channel, which are used for signal transmission. A Sounding Reference Signal is a fixed periodic transmission in the downlink, a signal that is sent by the eNB to all of its UEs. It allows UEs equipped with an SRS capability to measure channel quality; this information is then used by UEs to configure and adjust transmit power levels, optimize duplex configurations, and select transmission modes. Sound Reference Signal (SRS) is a special mandatory transmission that every base station or wireless network component must use when transmitting. This signal can be utilized by neighboring cells to estimate the strength of received signals and channels. The SRS is a useful mechanism for Listen-Before-Send (LBS) operation and is critical for the evaluation of UL/DL CoMP operation in 5G as well. With the global growth in the number of connected devices, there has been an increased demand for more mobile networks and more spectrum to meet these growing requirements. The 5G system calls for a massive increase in data transmission capacity and therefore requires efficient use of the available spectrum including its higher bandwidths. The sounding reference signal is a new feature provided by 3GPP to facilitate interference measurement at eNB/RAN nodes. 

SRS Sounder

The sounder as defined by 3GPP is a periodic sequence sent by each cell or RRH to assist other cells in estimating their channel quality to serve as reference signals for channel estimation and cancellation (CIC). The Sounding Reference Signal (SRS) is a signal transmitted over the uplink shared channel (UL-SCH) in a 5G network. Similar to the Transport Block Size Indicator (TBSI), it can be used by eNodeBs and UE devices to facilitate synchronization, although it differs in that it has additional channels for precise timing and frequency alignment. The use of this signal allows the eNodeBs to synchronize the devices, even when they have no measurements from previous transmissions. The Sounding Reference Signal (SRS) is a virtual signal transmitted by a transmitter, which can be used to estimate radio link and environment conditions.

SRS Transmission

The SRS is transmitted at regular intervals, usually every 10 ms, over an OFDM symbol. The SRS symbol contains information on the relative timing and power of the main signals that should be aligned to the 1/8th cycle. The sounding reference signal (SRS) is a type of physical uplink control channel. As such, it does not carry user traffic and can be used for ranging by the terminal to synchronize timing and frequency on the serving cell This can improve handover performance, especially when there are multiple serving cells in the same sector. The Sounding Reference Signal (SRS) is a downlink element of the sounding procedure. COST-206 covers this task in 3GPP technical specification 32.211. An SRS is a 13-subframe secondary synchronization signal sent to all UEs at specific times within each NFR2 frame, with 0.6 ms spacing between subframes, according to the UE’s measurement configuration and the cell re-selection configuration in use by that UE. For both UP-DL and DOWNLINK channels, an SRS subframe comprises one assigned slot and two optional slots if they exist according to the UE’s measurement configuration; where an assigned slot is effectively identical to a normal scheduled OFDMA/SC-FDMA/SC-CDMA (SS) slot, and an optional slot is treated as long as one OFDMA/SC-FDMA/SC. The Sounding Reference Signal provides a reference carrier and a set of basis signals for each cell. The elevation angle, azimuth angle, and power levels of the reference carrier are predetermined for each cell. The Sounding Reference Signal is transmitted on some subcarriers to convey system information throughout the cell.

The Sounding Reference Signal (SRS) is provisioned on the downlink of carrier aggregation transceivers in Release 14 NR (new radio) devices. An SR's carrier is transmitted by a UE at a constant DFT-SRS transmission periodicity. The signal can be used for acquisition, range and time synchronization measurements, detection of radio link failure, identification of an SCell from other Cells in an SCell pool, measurement of signal quality and signal bandwidth characteristics, generation of a reference for timing advance adjustment and cell initial estimation. The SRS contains only one physical layer tone that is orthogonal to all other carriers in a transmission block. The Sounding Reference Signal (SRS) is a downlink signal used to feed channel-sounding information to the UE. It consists of one or more repetitions, each containing a long access field, short access field, and the data field. The SRS is transmitted during the Physical Uplink Control Channel (PUCCH) or on PUCCH resources in uplink subframes. SRS is an advanced-sounding reference signal (SRS). It is considered the primary synchronization signal and is used to estimate either the time-alignment of a receiver or frequency-offset products in the synchronization, channel estimation and equalization stages of all multi-antenna receivers. 

5G SRS NR

The SRS 5G is a key component of the 5G standard, which features a massive increase in bandwidth, flexibility, and speed over current 4G technology. It will enable low latency and interference-free connectivity, support for massive numbers of devices, bigger data transfer rates, and higher quality streaming. Sounding Reference Signal 5G (SRS 5G) is a frequency-division duplex (FDD) uplink sounding reference signal for the 5G technology. It is used for mobile device measurements, with the related primary SC4 basic radio performance test emission measure (BPM) featured in TS38.101. SRS 5G is the most advanced sounding reference signal for 5G mobile communications. It is designed to provide a consistent user experience across all 3GPP bands and mode types. SRS 5G features a wide-bandwidth waveform, allowing it to be transmitted simultaneously with other signals and channels at different frequency bands. The Sounding Reference Signal (SRS) is a reference signal which is transmitted in the 5G mobile radio interface, to facilitate measurements of the channel quality of a 5G base station. The SRS uses 3GPP LTE-like standards, to enable compatibility with earlier LTE deployments and allow for early adoption. The SRS 5G is a sounding reference signal that is transmitted by cellular phones. The SRS transmission occurs periodically on a non-primary set of carriers and at appropriate power levels, such that an eNodeB can measure the quality of its synchronization to the User Equipment (UE) that it is serving. SRS for 5G is the signal that helps to build blocks to get ready for 5G. It contains information about signal characteristics like downlink (DL) and uplink (UL) clusters, subframe number, eNodeB identifier, and channel bandwidth. The SRS 5G is a sounding reference signal that is used in conjunction with the Extended Measurement Period.

SRS NR Purpose

The purpose of this sounding (which implements the third stage of 5G) is to provide a common measurement channel for all UEs that are measuring at the same time. This feature will allow both new and legacy UE categories to use the same measurement channel when testing against 3GPP specifications related to 5G NR physical layer measurements, including RN TRP, PUSCH N3 power level, etcetera. 5G will require a large number of SRS (sounding reference signals) which are reported in the measurement report that is sent back to the user equipment (UE). 

NR SRS Composition

The sounding reference signal (SRS) is made up of OFDM symbols where the resources are protected by CRC protection and scrambling. Based on the application and device requirements, there is an additional level of protection against interference from other cells. This protection can be through either physical layer or transport layer methods. SRS 5G is a short-term solution for the 5G networks due to its low complexity and implementation cost, which has been widely used as a reference signal in the existing LTE network. In this paper, we will first introduce the principle of SRS 5G and its features. Then, we will analyze the performance of SRS 5G with different waveforms and PAPR, which shows that the proposed method can effectively improve the performance of SRS 5G. Finally, we will compare our method’s performance with other methods using the simulation results. SRS 5G is a coordinated sounding procedure used to check radiofrequency interference among cells in a mobile phone system. It is the first step of test transmission. For each cell, transmitters are used to send a signal onto the air interface. SRS 5G is used by base stations to verify that they can communicate with their neighboring base stations.

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