Exemplary embodiments include methods for adjusting transmission timing of a wireless communication device (UE) operating in a network including first and second base stations (BS). The methods include determining a first allowable timing adjustment range corresponding to an uplink (UL) connection between the UE and the first BS, and determining a second allowable timing adjustment range corresponding to a supplementary uplink (SUL) connection between the UE and the second BS. The SUL connection is not associated with a DL connection between the UE and the second BS. The methods include determining if a single timing advance (TA) value can be used to adjust the UE's transmission timing to satisfy both the first and second ranges, and performing a corrective action if it is determined that a single TA value cannot be used. Embodiments also include first and second BS, and UEs, configured to perform the exemplary methods.

This application provides a pilot transmission method, including: determining, by a first terminal device, a target first pilot and a target second pilot group corresponding to the target first pilot, where the target first pilot is used by a network device to perform terminal device detection, and the target second pilot group includes at least two second pilots; and sending, by the first terminal device, the target first pilot and the target second pilot group to the network device in a time unit, where each second pilot in the target second pilot group is repeatedly sent on at least two symbols of the time unit, and the target second pilot group is used by the network device to perform frequency offset estimation.

Systems and methods for a non-data-aided (NDA) approach to advanced OFDM timing are provided. This approach allows for accurate OFDM symbol timing and synchronization by avoiding inter-symbol interference (ISI) in multipath environments where an earliest arriving signal may not be the strongest signal. The NDA approach may rely on generating and applying a bias correction to a combined correlation result of the multi-path signals.

A detection method for a MIMO system receiver in which a linear detection is carried out in order to provide an equalised vector. This equalised vector is represented in a reduced basis obtained from the reduction of the channel matrix. It undergoes an iterative noise cancellation process in the representation according to the reduced basis. Upon each iteration, a search is carried out for the component of the equalised vector in the reduced basis located the furthest from an area unperturbed by noise surrounding the product constellation with a tolerance margin, and the point representative of the equalised vector of this area by subtracting therefrom a noise vector in the direction of this component, the module whereof is equal to a fraction of the tolerance margin. The iterative cancellation converges when the equalised vector belongs to the area unperturbed by noise.

Methods, systems, and devices for wireless communications are described to enable base station and a user equipment (UE) to mitigate interference when using full-duplex communications. For example, a base station communicating with a UE via full-duplex communications may indicate for the UE to align the time of its uplink transmissions with the time the UE receives downlink transmissions. Additionally or alternatively, the base station may indicate a timing alignment window for the UE, where the window may consist of an allowed time period the UE may use to select a time to begin uplink transmissions. In some examples, the base station may select a cyclic prefix for full-duplex communications, where the cyclic prefix may be longer than a cyclic prefix used for other communications. Further, the base station may select uplink frequency and downlink frequency bands separated by a defined guard band for full-duplex communications.

Systems and methods are disclosed and include a method that includes adding a training symbol prefix to an OFDM symbol frame, the prefix including a plurality of training symbols, each including N sub-symbol fields. N/2 of the sub-symbol fields are zero valued, and N/2 of the sub-symbol fields carry corresponding symbols of a N/2 sub-symbol pseudo random training symbol. A first half of the pseudo random training symbol is symmetrical to a second half of the pseudo random training symbol. An OFDM N-sub-carrier transmission carries the prefix as signal power on a first N/2 of its N sub-carriers and suppresses signal power on a second N/2 of the sub-carriers. The first N/2 and second N/2 sub-carriers alternate in the frequency domain.

This application discloses a reference signal transmission method and apparatus. The method includes: generating one or more OFDM symbols, where at least one OFDM symbol includes a PTRS resource block, the PTRS resource block includes at least two of three sequences: a PTRS sequence of Y elements, X elements after the PTRS sequence, and Z elements before the PTRS sequence, and the PTRS resource block occupies a plurality of consecutive resource elements REs, where X, Y, and Z are all integers; and sending the one or more OFDM symbols. According to the foregoing method and apparatus, inter-carrier interference is reduced, thereby improving spectral efficiency.

Systems and methods are disclosed and include a method that includes adding a training symbol prefix to an OFDM symbol frame, the prefix including a plurality of training symbols, each including N sub-symbol fields. N/2 of the sub-symbol fields are zero valued, and N/2 of the sub-symbol fields carry corresponding symbols of a N/2 sub-symbol pseudo random training symbol. A first half of the pseudo random training symbol is symmetrical to a second half of the pseudo random training symbol. An OFDM N-sub-carrier transmission carries the prefix as signal power on a first N/2 of its N sub-carriers and suppresses signal power on a second N/2 of the sub-carriers. The first N/2 and second N/2 sub-carriers alternate in the frequency domain.

Embodiments of the present application provide a random access sequence generation method, and an apparatus. The method includes: generating, by a base station, notification signaling, where the notification signaling includes indication information, the indication information is used to instruct user equipment UE to select a shift sequence number from a range of 0 to (n.sub.shift.sup.RAn.sub.group.sup.RA+n.sub.shift.sup.RA+n.sub.shift.sup.RA+.sub.shift.sup.RA1), the shift sequence number is an integer, n.sub.shift.sup.RA is a quantity of UE candidate sequence shifts in a group, n.sub.group.sup.RA is a quantity of groups, n.sub.shift.sup.RA is a quantity of UE candidate sequence shifts in the last length that is insufficient for a group, n.sub.shift.sup.RA is a quantity of UE candidate sequence shifts in first remaining sequence shifts, and .sub.shift.sup.RA is a quantity of UE candidate sequence shifts in second remaining sequence shifts; and sending, by the base station, the notification signaling to the UE, so that the UE generates a random access sequence according to the indication information.

DM-RS symbols may be inserted in the beginning of a subframe, or in two parts of the subframe. In one aspect, a method, a computer-readable medium, and an apparatus for dynamically conveying DM-RS information are provided. The apparatus may be a base station. The apparatus may determine the number of DM-RS symbols and/or the locations within a subframe for transmission of the DM-RS symbols. The apparatus may transmit the number of the DM-RS symbols and/or the locations within the subframe for transmission of the DM-RS symbols to a UE. In another aspect, a UE may receive the number of DM-RS symbols and/or the locations within a subframe for transmission of the DM-RS symbols from a base station. The UE may decode the DM-RS symbols from the subframe based on the number of the DM-RS symbols and/or the locations within a subframe for transmission of the DM-RS symbols.