Provided are a data frame structure of a wireless communication system, which follows a sharing protocol which may be operated to coexist with a system that operates in an unlicensed spectrum, such as a WiFi system, and the like in the wireless communication system using a licensed spectrum such as an LTE system and an operation method of the system, and a terminal and a device of a base station for the operation.

The invention relates to a method for communicating based on a flexible TDD configuration by introducing flexible subframes, selectively usable as a downlink or uplink subframe in a manner avoids a transition from a (non-)flexible downlink subframe n to a (non-)flexible uplink subframe n+1. Furthermore, the invention allows reducing the number and types of uplink transmissions that would be pending for a flexible subframe, by defining HARQ uplink feedback timings based on the HARQ uplink feedback timings for the static TDD configurations such that HARQ uplink feedback is never transmitted in a flexible subframe, and also by releasing configurations for periodic uplink transmissions such as, SPS-scheduled uplink data transmissions, periodic CSI report, uplink sounding, random access, and scheduling requests.

Flexible employment of frame configuration in light of the Doppler frequency change is proposed. According to the present invention, frame configuration for a predetermined frequency band may be changed. Changing frame configuration in the present invention may include changing subcarrier spacing.

The disclosure relates to a method (200) performed by a control system (2, 3, 4) that controls the usage of a first carrier, which first carrier is divided into transmission segments and each transmission segment consisting of N transmission time intervals, where N is greater than or equal to 2. The method (200) comprises the control system (2, 3, 4): configuring (202) a first wireless communication device UE1 to transmit data on a physical traffic channel using the first carrier by transmitting the data only during a first subset of the N transmission time intervals in each transmission segment, wherein the first subset of the N transmission time intervals consists of n transmission time intervals and n<N; configuring (204) the first wireless communication device UE1 to transmit control information on a physical control channel using the first carrier by transmitting the control information during only the first subset of transmission time intervals in each transmission segment; and scheduling (206) a downlink transmission for the first wireless communication device UE1 such that a transmission of a feedback signal by the first wireless communication device UE1 in response to the downlink transmission will occur only during one or more of the transmission time intervals included in the first subset of transmission time intervals in each transmission segment.

A method of link adaptation is described including establishing, using a first serving point, a multi-user full duplex mode wherein the multi-user full duplex mode enables a downlink to a first wireless device and an uplink from a second wireless device. The first serving point requests from the first wireless device a first channel quality indicator indicating channel quality between the serving point and the first wireless device in a full duplex time period and a second channel quality indicator indicating channel quality between the serving point and the first wireless device in non-full duplex time period. The full duplex mode is evaluated using the first and second channel quality indicators. At least one parameter of the full duplex mode is adjusted based on the evaluating.

Embodiments of the present disclosure disclose a time domain position determination method. The method includes: obtaining, by a terminal, first indication information and second indication information, the first indication information indicating a starting position of a Fixed Frame Period (FFP), the second indication information indicating a time domain length of the FFP; and determining time domain positions of the FFP based on the starting position of the FFP and the time domain length of the FFP. Embodiments of the present disclosure further disclose a time domain position determination apparatus, a terminal, a computer-readable medium, a chip, and a computer program product.

Systems and methods for synchronizing communications between a User Equipment (UE) and Base Station (BS) using a synchronization signal structure. The synchronization signal structure can include a sequence of Synchronization Signals (SS) including repetitions of a synchronization signal burst set. The synchronization signal burst set can include a plurality of synchronization signal bursts. The synchronization signal bursts can include a plurality of synchronization signal blocks, wherein the synchronization signal blocks can include a plurality of Synchronization Signals (SS).

The method includes transmitting by a first remote communication unit an upstream symbol with a first structure onto a first communication line at a reference time point t.sub.rf, wherein the reference time point t.sub.rf is determined based on a time of reception of a downstream symbol with the first structure t.sub.FDX_DS_RX and a first propagation delay over the first communication line t.sub.PD1, as t.sub.rf=t.sub.FDX_DS_RX−t.sub.PD1; transmitting by a second remote communication unit an upstream symbol with a second structure onto the second communication line at t.sub.TDD_US_TX=t.sub.rf−t.sub.PD2 during a time interval assigned for upstream transmission on the second communication line, wherein t.sub.PD2 is a second propagation delay over the second communication line, so that the upstream symbol with the second structure transmitted by the second remote communication unit arrives at the access node at the reference time point t.sub.rf.

Communication apparatus is disclosed which is suitable for communicating with a mobile communication device in a communication system which uses a plurality of radio frames wherein each radio frame is subdivided in the time domain into a plurality of subframes, each subframe is subdivided in the time domain into a plurality of slots, and each slot is subdivided in the time domain into a plurality of symbols. The communication apparatus operates a communication cell, generates discovery signals, for use in a cell search procedure, each discovery signal comprising a pair of synchronisation signals and a further signal, and transmits each synchronisation signal and the further signal in a respective symbol of a radio frame. The symbol in which the further signal is transmitted separated, in the time domain, by no more than half a radio frame from at least one of said pair of synchronisation signals.

Techniques are described for millimeter wave wireless communication. One method includes configuring a synchronization slot associated with a plurality of synchronization blocks, configuring a transmission of each synchronization block of the plurality of synchronization blocks based on the configured synchronization slot, assigning a synchronization region to a first frequency portion associated with a transmission beam of each synchronization block, assigning at least one of a data region or a control region to a second frequency portion associated with the transmission beam of each synchronization block, and transmitting a synchronization signal during the synchronization region and transmitting at least one of data signal during the data region or control information during the control region to a wireless node.