Embodiments of efeMTC synchronization signals for enhanced cell search and enhanced system information acquisition are described. In some embodiments, an apparatus of a base station (BS) is configured to generate a length-x sequence for an efeMTC synchronization signal, the length-x sequence configured for repetition in frequency domain within 6 physical resource blocks (PRB). In some embodiments, to generate the length-x sequence, the BS may be configured to select any one index of the set of root indices {1, 2, 63}, excluding the root indices 25, 29 and 34, to correspond to a different physical-layer cell identity (PCID). In some embodiments, the BS may be configured to encode RRC signaling to include a System Information Block (SIB) comprising configuration information for transmission of the efeMTC synchronization signal, and transmit the length-x sequence as the efeMTC synchronization signal in frequency resources according to the SIB.

A base station for transmitting a synchronization signal from N transmission antennas (N>=2) in orthogonal frequency division multiple access includes a signal sequence generation unit configured to generate a synchronization signal sequence to be used for the synchronization signal in a frequency domain; a subcarrier mapping unit configured to divide a transmission band of the synchronization signal into K frequency blocks (K>=2) and map the synchronization signal sequence into one or more subcarriers in the K frequency blocks; a precoding unit configured to generate N precoding vectors to be multiplied by the synchronization signal sequence in the frequency domain and multiply the synchronization signal sequence to be transmitted from an n-th antenna (1<=n<=N) by at least an n-th precoding vector; and a transmission unit configured to transmit the synchronization signal from the N transmission antennas.

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.

Wireless communications for a plurality of cell groups are described. Uplink transmissions, such as uplink transport blocks, hybrid automatic repeat request (HARQ) transmission, and/or channel state information transmission, may be based on one or more time alignment timers associated with a cell group.

Apparatuses, methods, and systems are disclosed for transmitting a physical downlink shared channel after losing uplink synchronization. One method includes transmitting a physical downlink control channel order. The method includes transmitting a physical downlink shared channel transmission. The physical downlink control channel order and at least a portion of the physical downlink shared channel transmission are transmitted after a remote unit loses an uplink synchronization and before the remote unit completes a physical random access channel procedure. The method includes receiving feedback information corresponding to the physical downlink shared channel transmission.

Systems, apparatuses, and methods are described for wireless communications. A wireless device may distribute power for various transmission types based on a priority, which may be received from a base station.

A method and system for acquiring mmWave carrier in a wireless communication network is disclosed. In one embodiment, an MS acquires a low frequency carrier and then acquires the high frequency carrier. Since the low frequency carrier and the high frequency carrier are transmitted by same BS, the BS provides assistance information on the acquired low frequency carrier to the MS to acquire a synchronization signal which is transmitted on a high frequency carrier using beamforming. The assistance information includes synchronization signal beam time slots, synchronization signal beams which the MS needs to search, beam ID and so on. Based on the assistance information, the MS monitors the high frequency carrier to search and acquire the synchronization beam signal transmitted on the high frequency carrier. The MS determines the beam ID of the received synchronization beam signal and reports to the BS on the low frequency carrier.

Provided is a method and apparatus for using an offset between a synchronization signal block and a resource block grid. The method may include receiving, by a user device, a synchronization signal (SS) block comprising a synchronization signal and a physical broadcast channel (PBCH), determining, from the PBCH, a value of a subcarrier offset between the SS block and an RB grid, determining, based on the value of the subcarrier offset and a frequency location of the SS block, the RB grid, and decoding, based on the determined RB grid, one or more of a reference signal, a control channel, or a data channel.

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.

Embodiments of the present invention disclose a data processing method and apparatus, and belong to the field of communications technologies. The method includes: generating a physical layer protocol data unit PPDU, where the PPDU includes a preamble field, a data field, and a middle preamble field, and the preamble in the PPDU includes information used to indicate an insertion frequency of the middle preamble in the data field in the PPDU; and sending the PPDU. The insertion frequency of the middle preamble in the data field is indicated by using a specified field in the preamble. In this way, in different scenarios, the middle preamble may be inserted into the data field at different frequency, thereby reducing overheads of an inserted pilot and improving data transmission performance.