The application provides a short training sequence design method and apparatus. The method includes: determining a short training sequence, where the short training sequence may be obtained based on an existing sequence, and the short training sequence with comparatively good performance may be obtained through simulation calculation, for example, by adjusting a parameter, and sending a short training field on a target channel, where the short training field is obtained by performing inverse fast Fourier transformation IFFT on the short training sequence, and a bandwidth of the target channel is greater than 160 MHz.

In one embodiment, an apparatus includes: a radio frequency (RF) front end circuit to receive and downconvert a RF signal to a second frequency signal, the RF signal comprising an orthogonal frequency division multiplexing (OFDM) transmission; a digitizer coupled to the RF front end circuit to digitize the second frequency signal to a digital signal; and a baseband processor coupled to the digitizer to process the digital signal. The baseband circuit comprises a first circuit having a first plurality of correlators having an irregular comb structure, each of the first plurality of correlators associated with a carrier frequency offset and to calculate a first correlation on a first portion of a preamble of the OFDM transmission.

The user devices in managed networks, such as 5G and 6G networks, are required to adapt their uplink transmissions to the base station’s resource grid, including the timing and frequency structure of the resource grid. Message-heavy legacy synchronization procedures can consume substantial resources. Therefore, a simpler, faster procedure is disclosed in which synchronization parameters are standardized where possible, timing signals are configured in minimal size where possible, and the user device collaborates with the base station to adjust the user device’s clock setting, clock rate, timing advance (to match the base station’s symbol boundaries), and Doppler correction (to match the base station’s subcarrier frequency), without exchanging data messages other than very brief timing signals. Such ultra-lean synchronization procedures may enable low-complexity synchronization in future high-frequency communications.

High-frequency communications in 5G and especially 6G will require precise synchronization of user devices with the base station, including periodically setting the user device clock time and clock rate to mitigate oscillator drift. The base station can assist user devices by periodically providing a timing signal containing a mid-symbol timestamp point, which is a signal that includes an abrupt change in phase or amplitude centered in the symbol-time. A receiver can analyze the timing signal and determine precisely the time of arrival of the timestamp point, and correct the receiver's clock to ensure that uplink messages will then arrive at the base station synchronized with the base station's resource grid. In addition, the base station can provide two timing signals in which the mid-symbol timestamp points are separated by a predetermined separation, thereby assisting the user devices in adjusting their clock rates.

Techniques are described for carrier frequency offset (CFO) and channel estimation of orthogonal frequency division multiplexing (OFDM) transmissions over multiple-input multiple-output (MIMO) frequency-selective fading channels. A wireless transmitter forms blocks of symbols by inserting training symbols within two or more blocks of information-bearing symbols. The transmitter applies a hopping code to each of the blocks of symbols to insert a null subcarrier at a different position within each of the blocks of symbols, and a modulator outputs a wireless signal in accordance with the blocks of symbols. A receiver receives the wireless signal and estimates the CFO, and outputs a stream of estimated symbols based on the estimated CFO.

Exemplary embodiments provide a method and apparatus for transmitting a synchronization signal for Device-to-Device (D2D) communication in a wireless communication system. The method includes: receiving, at a first UE, a D2D synchronization signal transmitted from a second UE, the D2D synchronization signal comprising a primary D2D synchronization signal (PD2DSS) and a secondary D2D synchronization signal (SD2DSS); determining a root index based on the received PD2DSS; and determining a type of a synchronization source based on the root index. The root index corresponds to an integer value X when the type of synchronization source is associated with D2DSSue_net. The root index corresponds to an integer value Y when the type of synchronization source is associated with D2DSSue_oon. Each of the integer value X and integer value Y is not an element of a set {25, 29, 34}.

Provided is a method and apparatus for receiving a reference signal. A wireless user device may determine, based on a synchronization signal (SS) block index and based on an index associated with a time interval, an initialization value associated with a reference signal for a physical broadcast channel (PBCH). The wireless user device may receive, based on the initialization value and based on a frequency domain shift value, the reference signal via at least one resource element (RE). The reference signal may be mapped, based on the frequency domain shift value, to the at least one RE. The wireless user device may receive the PBCH.

New sequences have been proposed and/or adopted for short Physical Uplink Control Channel communications between base stations and UEs. In an exemplary embodiment, a UE communicates with a base station based on sequence groups that include the new sequences, where the new sequences are allocated to different sequence groups based, at least in part, on correlations with other existing sequences included in individual sequence groups.

Provided are a preamble symbol receiving method and device, characterizing in that the method comprises the following steps: processing a received signal; judging whether the processed signal obtained contains the preamble symbol desired to be received; and if a judgement result is yes, determining the position of the preamble symbol and resolving signalling information carried by the preamble symbol, wherein the received preamble symbol comprises at least one time-domain symbol generated by a transmitting end using a free combination of any number of first three-segment structures and/or second three-segment structures according to a predefined generation rule, the first three-segment structure containing: a time-domain main body signal, a prefix generated based on the entirety or a portion of the time-domain main body signal, and a postfix generated based on the entirety or a portion of a partial time-domain main body signal, and the second three segment structure containing: the time domain main body signal, a prefix generated based on the entirety or a portion of the time domain main body signal, and a hyper prefix generated based on the entirety or a portion of the partial time domain main body signal.

According to embodiments described herein, a long delay-detector improves delay estimation performance for PRACH for many practical deployment scenarios. This, for example, reduces the risk that the timing advance of the UE is set incorrectly and hence reduces the risk that subsequent communication fails and that the UE spreads unnecessary interference to other communication in the system.