A duplex communication method, base station, and terminal

Abstract

The present application discloses a bidirectional communication method and device. In the present application, one of the uplink control channel and the downlink control channel is transmitted in the first sub-band and the third sub-band of the available continuous frequency band respectively, and control channels in different directions are transmitted in the first sub-band and the third sub-band at the same time; in the second sub-band of the available continuous frequency band, uplink data and downlink data are transmitted in a time-division multiplexing manner; wherein, the first sub-band and the third sub-band are located at both ends of the available continuous frequency band. Applying the present application can improve the spectrum utilization rate and performance of the wireless communication system.

Description

[0001] This application is a divisional application of the invention patent application with the application date of November 13, 2015 and the application number of 201510779297.0. Technical Field

[0002] This application relates to the field of wireless communication technologies, and particularly to a duplex communication method, a base station, and a terminal. Background Art

[0003] The rapid development of the information industry, especially the growing demands from the mobile Internet and the Internet of Things (IoT), has brought unprecedented challenges to future mobile communication technologies. For example, according to the report ITU-R M.[IMT.BEYOND 2020.TRAFFIC] of the International Telecommunication Union (ITU), it is expected that by 2020, the mobile traffic will increase nearly 1000 times compared with 2010 (the 4G era), and the number of connected terminal devices will also exceed 17 billion. As a large number of IoT devices gradually penetrate into the mobile communication network, the number of connected devices will be even more astonishing. To address these unprecedented challenges, the communication industry and academia have launched extensive research on fifth-generation mobile communication technologies (5G) for the 2020s. Currently, in the report ITU-R M.[IMT.VISION] of the ITU, the framework and overall goals of future 5G are being discussed, which details the demand outlook, application scenarios, and various important performance indicators of 5G. In response to the new requirements in 5G, the report ITU-R M.[IMT.FUTURE TECHNOLOGY TRENDS] of the ITU provides relevant information on 5G technology trends, aiming to solve significant problems such as a significant increase in system throughput, consistency of terminal experience, scalability to support IoT, latency, energy efficiency, cost, network flexibility, support for emerging services, and flexible spectrum utilization.

[0004] The duplex mode in wireless communication refers to the processing method of two-way data communication between the uplink and the downlink, which is an important basis for the design of the wireless communication air interface. The research and development of 5G is no exception. Currently, Frequency Division Duplex (FDD) and Time Division Duplex (TDD) are two main duplex modes and are widely used in the fields of broadcast audio and video as well as civil communication systems, such as the Long-Term Evolution (LTE) system corresponding to the Evolved Universal Terrestrial Radio Access (E-UTRA) protocol formulated by the 3rd Generation Partnership Project (3GPP), the IEEE802.11a / g Wireless Local Area Network (WLAN), etc.

[0005] In the FDD mode, the uplink and the downlink communicate using paired frequency resources that meet a certain duplex spacing, while in the TDD mode, the uplink and the downlink share the same frequency resources, and the uplink communication and the downlink communication are divided by different time resources. Different duplex modes will lead to different designs of the physical layer of the air interface such as the frame structure. Taking LTE as an example, two frame structures applicable to the FDD mode and the TDD mode are specified in LTE.

[0006] The frame structure of FDD is as Figure 1 shown. A 10ms wireless frame consists of 10 subframes with a duration of 1ms each, and each subframe consists of two time slots with a duration of 0.5ms. The uplink communication and the downlink communication are carried out on different frequency resources.

[0007] The frame structure adopted by the TDD mode is as Figure 2 shown. Similar to the FDD mode frame structure, a 10ms wireless frame consists of ten subframes with a duration of 1ms. The difference is that in the TDD mode, the uplink communication and the downlink communication share the same frequency resources and are distinguished by time resources. For example Figure 2 in the configuration, subframes 0 and 5 are used for downlink communication, and subframes 2, 3, 4, 7, 8, and 9 are used for uplink communication. To ensure that the downlink communication does not affect the uplink communication, the frame structure of the TDD mode introduces special subframes, that is Figure 2Subframe 1 and subframe 6 in it. The special subframe consists of three domains: Downlink Pilot Time Slot (DwPTS), Guard Period (GP), and Uplink Pilot Time Slot (UpPTS). In the frame structure of the TDD mode, subframe 1, 5, and DwPTS are always used for downlink transmission, while UpPTS and the subsequent subframes are always used for uplink transmission. GP is the guard interval between downlink communication and uplink communication to ensure that uplink data communication will not be affected by downlink communication. The TDD mode in LTE can be flexibly configured to support services with asymmetric downlink and uplink data communication. Table 1 shows various configurations of the TDD mode in LTE, where D indicates that the subframe is used for downlink communication, U indicates that the subframe is used for uplink communication, and S indicates the special subframe.

[0008] Table 1: Uplink and Downlink Configurations of the TDD Mode in LTE

[0009]

[0010] The above two duplex modes each have their own advantages and disadvantages. Specifically: The FDD mode needs to complete uplink and downlink data communication in paired frequency bands. The uplink and downlink frequency pairing needs to meet a certain duplex interval. When 5G develops towards high frequencies and large bandwidths, from the perspective of spectrum division, it is likely to lead to spectrum fragmentation and is not conducive to spectrum management. While the TDD mode uses the same frequency band to complete uplink and downlink data communication. Therefore, the TDD mode has an advantage in the flexibility of frequency resource utilization, can support more asymmetric services, and has a higher spectrum utilization efficiency; Since FDD has paired spectra, there are always available uplink and downlink resources. Then, the scheduling and terminal feedback of uplink control signaling can be relatively timely, such as the acknowledgment messages (ACK / NACK, Acknowledge / Non-Acknowledge) of Hybrid Automatic Retransmission Request (HARQ) and Channel State Information (CSI, Channel state information), thus reducing the feedback delay of the air interface and improving the scheduling efficiency. However, different uplink and downlink time slot configurations in TDD will make the related design more complex; In addition, the TDD mode has the advantage of channel reciprocity between uplink and downlink, which can greatly simplify the acquisition of CSI.

[0011] In 5G, large-scale MIMO technology may be adopted to further improve spectral efficiency. A large number of antennas are equipped at the base station side. Then, in the FDD mode, a large amount of resources are required for downlink physical channel training and feedback of channel state information. By utilizing the channel reciprocity in the TDD mode, the overhead of training and feedback can be significantly reduced. Therefore, the TDD mode is more attractive for large-scale MIMO technology. However, in 5G, there are also requirements for low latency, which requires further shortening the air interface transmission time interval (Transmission Time Interval, TTI) and more timely control signaling, which will make the design of the TDD mode more complex.

[0012] As can be seen from the above analysis, the FDD mode and the TDD mode have their own advantages and disadvantages. Facing the richer application scenarios and the use of new frequency bands in 5G, it is necessary to design a new duplex mode to integrate the advantages of the FDD mode and the TDD mode in order to better ensure the spectral utilization rate and network performance of 5G. Summary of the Invention

[0013] The technical problem to be solved by the present invention is that the FDD mode and the TDD mode in a wireless communication system operate independently and cannot be combined with each other, thus restricting the spectral utilization rate and performance of the wireless communication system. For this reason, the present invention provides a duplex communication method, a base station, and a terminal based on the in-band frequency band.

[0014] A bidirectional communication method provided by the present application includes:

[0015] Transmitting one of the uplink control channel and the downlink control channel in the first sub-band and the third sub-band of the available continuous frequency band respectively, and transmitting control channels in different directions in the first sub-band and the third sub-band at the same time;

[0016] Transmitting uplink data and downlink data in the second sub-band of the available continuous frequency band in a time-division multiplexing manner;

[0017] Wherein, the first sub-band and the third sub-band are located at both ends of the available continuous frequency band.

[0018] Preferably, there is a guard band between the first sub-band and the second sub-band, and there is a guard band between the second sub-band and the third sub-band, and no signal is transmitted in the guard band.

[0019] Preferably, the size of the guard band is set according to the interference level between adjacent sub-bands and the out-of-band leakage suppression method adopted.

[0020] Preferably, the method further includes: the base station adjusts the size of the guard band through at least one of the following guard band modes:

[0021] Insert an additional guard band within at least one sub - band;

[0022] Adjust the center frequency point of at least one sub - frame in the data channel on the second sub - band.

[0023] Preferably, the method further includes: the base station dynamically adjusts the guard band mode according to the received signal strength of the uplink data, and indicates the guard band mode currently used by the terminal through a predefined method, or a broadcast channel, or a downlink control channel.

[0024] Preferably, the method further includes: the base station stores the correspondence between the guard band mode and its index in a look - up table, and indicates the guard band mode currently used by the terminal by indicating the index of the corresponding mode to the terminal.

[0025] Preferably, in the guard band mode of inserting an additional guard band within the sub - band, the adjusted parameters include: the position and size of the additional guard band inserted in the control channel and / or data channel;

[0026] In the guard band mode of adjusting the center frequency point of the data channel, the adjusted parameter includes: the offset of the center frequency point of the data channel.

[0027] Preferably, the method further includes: the base station notifies the terminal of the positions and bandwidths of each sub - band within the available continuous frequency band, as well as the configuration of the uplink and downlink communications in the data channel, and communicates with the terminal according to the agreed configuration.

[0028] Preferably, the downlink control channel is used to transmit downlink control signaling, and the downlink control signaling includes at least one of the following information: resource allocation information, coding and modulation information, hybrid automatic repeat request information, uplink transmission authorization, uplink transmission power control indication;

[0029] The uplink control channel is used to transmit uplink control signaling, and the uplink control signaling includes at least one of the following information: scheduling request, hybrid automatic repeat confirmation / non - confirmation information, channel state information;

[0030] The second sub - band is used to transmit uplink data and downlink data, and is also used to transmit at least one of the following channels: synchronization channel, broadcast channel for transmitting system information, and uplink random access channel.

[0031] Preferably, the first sub - frame of each radio frame is used for downlink transmission.

[0032] Preferably, the method further includes: the base station sends an uplink handover indication and / or a downlink handover indication on the downlink control channel to change the transmission direction of the sub - frames in the data channel.

[0033] Preferably, the method further includes: transmitting an uplink handover indication at least once in a downlink control channel of each radio frame, and at least one subframe in a data channel is used for uplink data communication.

[0034] Preferably, the method further includes: inserting a guard interval when the channel switches from downlink transmission to uplink transmission, and no signal is transmitted in the guard interval.

[0035] Preferably, the method further includes: inserting a special subframe when the downlink transmission switches to the uplink transmission;

[0036] The special subframe includes: a downlink special time slot, a guard interval, and an uplink pilot time slot, where:

[0037] The downlink special time slot is used for downlink communication, and the transmitted content includes at least one of the following information: a downlink data channel, a physical synchronization channel, and a physical broadcast channel;

[0038] The uplink pilot time slot is used to carry a sounding pilot signal;

[0039] No signal is transmitted in the guard time slot.

[0040] Preferably, a filter-based or filter bank-based single-carrier or multi-carrier modulation method is used on each sub-band;

[0041] The filter-based or filter bank-based single-carrier or multi-carrier modulation method includes at least one of the following modulation methods: filter bank multi-carrier FBMC based on subcarrier filtering, Filtered-OFDM based on band filtering, and single-carrier filter bank multi-carrier SC-FBMC based on band filtering.

[0042] Preferably, the method further includes: adjusting the frequency domain focusing of the filter or filter bank to match the size of the guard band.

[0043] Preferably, the method further includes: dividing a second sub-band into at least two sub-bands, and using different physical layer parameters of filter-based or filter bank-based single-carrier or multi-carrier modulation for different sub-bands.

[0044] Preferably, one of the uplink control channel and the downlink control channel is respectively transmitted in the first sub-band and the third sub-band of the available continuous frequency band, including: alternately transmitting the downlink control channel and the uplink control channel in the first sub-band, and at the same time, transmitting a control channel in the third sub-band in a direction different from that of the first sub-band.

[0045] Preferably, there is a guard interval between the downlink control channel and the uplink control channel in the same sub-band, and no signal is transmitted in the guard interval.

[0046] Preferably, the first sub-band and the third sub-band have the same alternating frequency for transmitting control channels, which is notified to the terminal in a predefined manner, by the base station through a downlink control channel, or through a broadcast channel in the first sub-frame.

[0047] Preferably, the method further includes: the base station transmits control signaling in a data channel within the second sub-band, and notifies the terminal whether to transmit control signaling in the data channel within the second sub-band through a downlink control channel within the first sub-band or a broadcast channel within the second sub-band;

[0048] Among them, the manner in which the base station transmits control signaling in the data channel within the second sub-band includes at least one of the following manners: using a part of the time-frequency resources of the downlink sub-frame within the data channel to transmit the signaling within the downlink control channel, and using a part of the time-frequency resources of the uplink sub-frame within the data channel to transmit the signaling within the uplink control channel.

[0049] This application also provides a base station, including: a control transmission module and a data transmission module, where:

[0050] The control transmission module is used to transmit one of the uplink control channel and the downlink control channel in the first sub-band and the third sub-band of the available continuous frequency band respectively, and transmit control channels in different directions within the first sub-band and the third sub-band at the same time;

[0051] The data transmission module is used to transmit uplink data and downlink data in a time-division multiplexing manner in the second sub-band of the available continuous frequency band;

[0052] Among them, the first sub-band and the third sub-band are located at both ends of the available continuous frequency band.

[0053] This application also provides a terminal access method, including:

[0054] The terminal completes the cell search process by receiving the synchronization channel and the broadcast channel at the center position of the second sub-band, and obtains the system configuration information by reading the physical broadcast channel, where the time-frequency positions of the synchronization channel and the broadcast channel are pre-configured in the frame structure; the system configuration information includes at least one of the following information: system bandwidth, uplink and downlink communication configuration, guard band configuration, control channel hopping configuration;

[0055] The terminal obtains the center frequency point position and bandwidth of the uplink and downlink control channels, the center frequency point position and bandwidth of the service channel, and the uplink and downlink data communication configuration through the system configuration information in the physical broadcast channel;

[0056] The terminal obtains the system configuration information carried on the downlink data channel through the downlink control channel, and initiates and completes the uplink access according to the configuration information;

[0057] The terminal communicates with the base station according to the agreed-upon uplink and downlink communication configurations.

[0058] Preferably, the terminal obtains the uplink and downlink communication configurations, guard band configurations, and control channel hopping configurations by receiving the indexes required for the lookup table from the base station.

[0059] Preferably, the terminal determines the positions of acknowledgments / non-acknowledgments (ACK / NACK) of hybrid automatic repeat request (HARQ) for uplink and downlink based on the subframe positions in the data channel used for uplink and downlink data communication.

[0060] Preferably, the terminal determines the positions of ACK / NACK of uplink and downlink HARQ based on a fixed HARQ round-trip time (RTT).

[0061] This application also provides a terminal device, which includes: a cell search module, a configuration information acquisition module, an access module, and a communication module, where:

[0062] The cell search module is used to complete the cell search process by receiving the synchronization channel and broadcast channel at the center position of the second sub-band, and obtain the system configuration information by reading the physical broadcast channel. The time-frequency positions of the synchronization channel and the broadcast channel are pre-configured in the frame structure; the system configuration information includes at least one of the following information: system bandwidth, uplink and downlink communication configurations, guard band configurations, and control channel hopping configurations;

[0063] The configuration information acquisition module is used to obtain the center frequency point positions and bandwidths of the uplink and downlink control channels, the center frequency point positions and bandwidths of the service channels, and the uplink and downlink data communication configurations through the system configuration information in the physical broadcast channel.

[0064] The access module is used to obtain the system configuration information carried on the downlink data channel through the downlink control channel, and initiate and complete uplink access according to the configuration information.

[0065] The communication module is used to communicate with the base station according to the agreed-upon uplink and downlink communication configurations.

[0066] The bidirectional communication method and device disclosed in this application transmit one of the uplink control channel and the downlink control channel in the first sub-band and the third sub-band of the available continuous frequency band respectively, and transmit control channels in different directions in the first sub-band and the third sub-band at the same time; and transmit uplink data and downlink data in the second sub-band of the available continuous frequency band in a time-division multiplexing manner, so that it is not necessary to allocate multiple segments of spectrum, and sub-bands can be directly divided within the continuous bandwidth, and out-of-band leakage suppression technology and guard bands are used to reduce interference between sub-bands, which can improve the spectrum utilization rate and performance of the wireless communication system. Description of the Drawings

[0067] Figure 1 It is a schematic diagram of the frame structure of the FDD mode in the existing LTE;

[0068] Figure 2 It is a schematic diagram of the frame structure of the TDD mode in the existing LTE;

[0069] Figure 3 It is a schematic diagram of the hybrid duplex mode within the frequency band of this application;

[0070] Figure 4 It is a schematic diagram for comparing the sub - carrier waveforms of FBMC and OFDM;

[0071] Figure 5 It is a schematic diagram for comparing the spectra of F - OFDM and OFDM;

[0072] Figure 6 It is a schematic diagram of a preferred frame structure of this application;

[0073] Figure 7 It is a schematic diagram of a preferred duplex frequency band division of this application;

[0074] Figure 8 It is a schematic diagram of a preferred data communication structure of this application;

[0075] Figure 9 It is a schematic diagram of a preferred flexible configuration of uplink and downlink data communication of this application;

[0076] Figure 10 It is a schematic diagram of a preferred hybrid duplex mode within the frequency band with a guard band inserted in the data channel of this application;

[0077] Figure 11 It is a preferred hybrid duplex mode with a guard band inserted in the control channel of this application;

[0078] Figure 12 It is a preferred hybrid duplex mode for adjusting the center frequency of the data channel of this application;

[0079] Figure 13 It is a schematic diagram of a preferred way of hopping transmission of the control channel of this application;

[0080] Figure 14 It is a schematic diagram of a preferred way of transmitting control signaling within the data channel of this application;

[0081] Figure 15 It is a schematic diagram of a preferred downlink HARQ timing of this application;

[0082] Figure 16 It is a schematic diagram of a preferred uplink HARQ timing of this application;

[0083] Figure 17 This is a preferred synchronization and broadcast channel configuration structure for this application;

[0084] Figure 18 This is a schematic diagram of the composition structure of a preferred base station device for this application;

[0085] Figure 19 This is a schematic diagram of the composition structure of a preferred terminal device for this application. Detailed implementation manners

[0086] To make the objectives, technical solutions and advantages of this application clearer and more understandable, the following examples are given with reference to the accompanying drawings to further elaborate on this application in detail.

[0087] This application proposes a two-way communication method for separating control and data within a frequency band, which is referred to as "In-band Hybrid Duplex" for convenience of description. "In-band" means that this application does not require the allocation of multiple spectrum segments and can directly divide sub-bands within a continuous bandwidth (un-paired spectrum), and uses out-of-band leakage suppression techniques (such as filter-based waveform modulation techniques) and guard bands to reduce interference between sub-bands. The basic schematic diagram of the in-band hybrid duplex solution of this application is as Figure 3 shown.

[0088] Figure 3 In the figure, the time-frequency resources for data transmission are divided into three parts in frequency. Among them, the two sub-bands at the edges are respectively used for transmitting the uplink control channel and the downlink control channel, and the sub-band in the middle is used for transmitting data (also referred to as the "data sub-band" hereinafter). To prevent interference between the data channel and the control channel, guard bands are inserted between the sub-bands. The control channel and the data channel perform duplex communication in a manner similar to frequency division duplex, while the data channel is transmitted in a manner similar to time division duplex, that is, the uplink data and the downlink data share the same frequency band, but are distinguished in time. A guard interval is inserted when the downlink data transmission is switched to the uplink data transmission for the switching protection time from downlink to uplink and to prevent serious interference caused by time division multiplexed downlink transmission to uplink reception.

[0089] To reduce the loss of spectral efficiency caused by guard bands, the present invention adopts single-carrier or multi-carrier modulation based on filters or filter banks, including but not limited to Filter-bank Multicarrier (FBMC) technology based on sub-carrier filtering (Reference: "Analysis and design of OFDM / OQAM systems based on filter bank theory", IEEE Transactions on Signal Processing, Vol. 50, No. 5, 2002), Filtered-OFDM (F-OFDM) technology based on band filtering (Reference: "The effect of filtering on the performance of OFDM systems," IEEE Trans. Veh. Tech., vol. 49, no. 5, pp. 1877-1884, 2000.), Single-carrier Filter-bank Multicarrier (SC-FBMC) technology based on sub-filtering, etc. A common goal of these technologies is to filter the signal through filters to suppress out-of-band leakage, that is, the crosstalk between sub-bands is small, so the design of the guard band size can be adjusted according to the implementation of the filter. Among them, single-carrier or multi-carrier modulation based on filters or filter banks includes: single-carrier modulation based on filters, multi-carrier modulation based on filters, single-carrier modulation based on filter banks, and multi-carrier modulation based on filter banks.

[0090] By using FBMC, a signal waveform with good time-frequency focusing can be obtained, such as prototype filter functions based on the Isotropic Orthogonal Transform Algorithm (IOTA), the Extended Gaussian Function, and PHYDYAS in Europe. When using FBMC, a shaping filter with very good time-frequency domain focusing (Time / Frequency Localization, TFL) is used to perform pulse shaping on the signals of each subcarrier, which enables: FBMC can greatly suppress inter-symbol interference (ISI) caused by multipath without the need for a cyclic prefix. It can not only bring higher spectral efficiency and energy efficiency compared to OFDM, but also obtain good reception robustness under a larger time error, thus allowing for non-strictly synchronous transmission; thanks to good frequency focusing, FBMC can transmit signals within an extremely narrow frequency resource and maintain very low out-of-band leakage, thereby better suppressing inter-carrier interference (ICI) caused by Doppler or phase noise, etc. Therefore, FBMC can make the guard band required for implementing in-band hybrid duplex smaller, and the saved cyclic prefix overhead can compensate for the guard band overhead to a certain extent, thus making Figure 3 the in-band hybrid duplex mode shown competitive in 5G from the perspective of spectral efficiency.

[0091] Figure 4 The schematic diagram of the subcarrier frequency waveforms of FBMC using the PHYDYAS filter and orthogonal frequency division multiplexing (OFDM) technology using a rectangular window function is shown. It can be seen that compared with OFDM technology, FBMC has better frequency domain focusing, the attenuation rate of the frequency domain waveform is very fast, and it only has very low out-of-band leakage. Therefore, it is very suitable for Figure 3 the in-band hybrid duplex structure shown, which can effectively reduce adjacent channel interference while effectively reducing the frequency band occupied by the guard band and reducing the overhead brought by the guard band.

[0092] Figure 5The figure shows a schematic diagram of the spectrum comparison between F-OFDM and OFDM when the number of valid subcarriers is 64. The filter used in the F-OFDM technology is obtained by multiplying the sinc function with the Hanning window in the time domain. It can be seen that, compared with the OFDM technology, the out-of-band attenuation rate of the F-OFDM spectrum is significantly faster. After several subcarriers outside the frequency band, the out-of-band leakage will drop to a relatively low level. Therefore, it can reduce the spectrum efficiency loss caused by the guard band. Designing a better filter for F-OFDM can make the out-of-band attenuation faster, but a trade-off needs to be made with the complexity and signal distortion index.

[0093] Figure 3 The technical advantages of the in-band hybrid duplex structure shown are as follows:

[0094] 1. It does not require paired spectrum resources, and the resource scheduling and configuration of uplink and downlink communications are more flexible. Then, for the new frequency bands of 5G, large contiguous bandwidths can be allocated in an unpaired form, avoiding frequency band fragmentation.

[0095] 2. The uplink and downlink control channels are transmitted across the entire frequency band. Therefore, a timing structure similar to that of HARQ in the FDD mode can be adopted, avoiding the problems of chaotic HARQ timing and low efficiency in the TDD mode.

[0096] 3. Through the enhancement of the Sounding Reference Signal (SRS) on the data subcarriers, the downlink channel estimation can be obtained by using the channel reciprocity through the channel estimation of the uplink channel. This feature can effectively reduce the overhead of channel training and feedback in large-scale MIMO systems and is very suitable for high-frequency band communications and large-scale MIMO technologies in 5G wireless communications.

[0097] To support the in-band hybrid duplex mode, the terminal needs to have the ability to process signals in different sub-bands simultaneously. Considering that current mobile communication devices can basically support both the FDD mode and the TDD mode, they all have the ability to process signals in different sub-bands and can also support the in-band hybrid duplex mode provided by this application. In addition, when using the in-band hybrid duplex mode, based on FBMC modulation, asynchronous transmission and unlicensed small packet data transmission can still work in the time-division duplex mode on the data subcarriers.

[0098] The technical solution of this application will be further described in detail through several preferred embodiments below.

[0099] Embodiment 1:

[0100] In this embodiment, we introduce a communication system based on in-band hybrid duplex mode in combination with specific system parameter settings. This embodiment assumes that the application scenario is a 5G mid-high frequency band communication scenario, such as a communication system operating in the millimeter wave band. To improve the system spectrum utilization rate and reduce out-of-band leakage, the system adopts new waveform multi-carrier modulation technologies with less out-of-band leakage and faster out-of-band attenuation, such as FBMC or F-OFDM. Assume that the system operates in the 28 GHz band, the system bandwidth is 150 MHz, and the sub-carrier spacing is 300 kHz. At this time, the duration of a multi-carrier symbol is about 3.33 us, and the size of the fast Fourier transform (FFT) used for multi-carrier modulation is 512. The structure of the radio frame in LTE is still used, that is, a radio frame is composed of sub-frames, and a sub-frame is composed of time slots. In this embodiment, a time slot is composed of 15 multi-carrier modulation symbols, with a duration of 0.05 ms; a sub-frame is composed of two time slots, with a duration of 0.1 ms; a radio frame is composed of 10 sub-frames, with a duration of 1 ms. The frame structure described in this embodiment is as Figure 6 shown, and the symbols in the figure refer to multi-carrier modulation symbols. It should be noted that this embodiment adopts the FBMC new waveform modulation technology, and this kind of technology can well suppress the inter-symbol interference (ISI) caused by the multi-path channel without adding a cyclic prefix (CP).

[0101] Figure 7 The schematic diagram of the spectrum structure of the solution provided in this embodiment is shown as follows. Define a sub-carrier on a multi-carrier symbol as a resource element (RE). A resource block contains 20 sub-carriers on 15 multi-carrier symbols, that is, it contains 300 REs, with a bandwidth of 6 MHz and a duration of 0.05 ms. Figure 7 The spectrum structure shown occupies a bandwidth of 150 MHz, and the available sub-carriers are 500.

[0102] As Figure 7 shown, the available bandwidth is divided into four parts according to functions, namely the uplink control channel, the downlink control channel, the data channel, and the guard band. 15 sub-carriers on both sides of the frequency band edge are respectively used for the transmission of the uplink control channel and the downlink control channel. 460 sub-carriers in the middle of the frequency band are used for data transmission. 5 sub-carriers are left between the control channel and the data channel as a protection interval to reduce or eliminate the mutual interference between the control channel and the data channel. As Figure 4 can be seen, the out-of-band leakage of the 5 empty sub-carriers can be rolled down to below 100 dB.

[0103] Considering the adoption of the new waveform modulation method, compared with the OFDM technology, the out-of-band leakage will be greatly reduced. Therefore, only a relatively small frequency band needs to be reserved as the guard band to effectively reduce or even eliminate the mutual interference between the data channel and the control channel. The size of the guard band is related to the out-of-band suppression ability of the new waveform modulation method, that is, the frequency-domain focusing of the filter can be adjusted to match the size of the guard band. In this embodiment, 5 subcarriers are reserved as the guard band between the data channel and the downlink control channel and between the data channel and the uplink control channel respectively. The bandwidth occupied by the guard band is 1.5 MHz. For the new waveform technology with low out-of-band leakage, such as FBMC, etc., it is sufficient to eliminate the inter-channel crosstalk caused by the out-of-band leakage. And the two 1.5-MHz guard bands only occupy 2% of the entire frequency band bandwidth. Compared with the 10% bandwidth reserved as the guard band in the current LTE OFDM system to meet the spectrum leakage and the CP overhead exceeding 6%, the overhead can be almost ignored.

[0104] Figure 7 The functions of each of the channels shown are briefly described as follows:

[0105] The downlink control channel is used to transmit downlink control signaling, which may include: resource allocation information, modulation and coding scheme (MCS) for each codeword, HARQ information, layer information in multi-layer transmission, power control commands for the uplink control channel, aperiodic SRS transmission trigger, etc. At the same time, the downlink control channel is also used to transmit HARQ indication information. That is, the downlink control channel at least includes something similar to the PDCCH and PHICH in LTE.

[0106] The uplink control channel is used to transmit uplink control signaling, which may include: scheduling request (SR), HARQ acknowledgment / non-acknowledgment (ACK / NACK) information, channel state information (CSI), etc. Among them, CSI includes channel quality indicator (CQI), and rank indicator (RI) and precoding matrix indicator (PMI) for MIMO transmission feedback. That is, the uplink control channel at least includes something similar to the PUCCH in LTE.

[0107] The data channel is used to transmit uplink and downlink data, and also includes a synchronization channel, a broadcast channel for transmitting system information, and an uplink random access channel, etc. That is, it at least includes something similar to the PUSCH, PDSCH, PRACH, PBCH, and SCH in LTE. Since the data channel is used for both uplink and downlink data communication, and the uplink and downlink data are distinguished by different times, it is necessary to insert a guard time when switching from downlink communication to uplink communication to provide a handover guard time and avoid serious interference from downlink communication to uplink communication. Similar to the frame structure of the TDD mode in LTE, special subframes can be inserted when switching from downlink communication to uplink communication to provide protection when switching from downlink communication to uplink communication. A preferred data frame structure of this application is as Figure 8 shown. See Figure 8 :

[0108] The special subframe includes three parts, namely the downlink special time slot, the guard interval, and the uplink pilot time slot. The downlink special time slot is used for downlink communication, and the transmitted content can include one or a combination of the following: downlink data channel, physical synchronization channel, physical broadcast channel; the uplink pilot time slot is used to carry the sounding pilot signal; the guard time slot does not transmit any signal and is used to provide the time required for radio frequency switching from downlink to uplink and necessary to prevent interference from downlink transmission to uplink reception. Taking the FBMC technology as an example, considering its longer time-domain tail, a longer guard time slot needs to be provided to ensure that downlink data does not interfere with uplink communication. For example, for the FBMC technology with an overlapping factor of 4, the guard interval needs to be greater than 4 multi-carrier symbols. If other multi-carrier modulation technologies with shorter time-domain tails are used, the guard interval can be shortened.

[0109] In the in-band hybrid duplex mode provided by this application, the ratio of uplink and downlink data communication can be adjusted according to the requirements of uplink and downlink services. For example, it can be adjusted according to the subframe ratio of uplink and downlink communication shown in Table 1, and the Physical Broadcast Channel (PBCH) is fixedly sent in subframe 0 to indicate the uplink and downlink communication configuration used by this radio frame. Therefore, the in-band hybrid duplex mode can adapt to the requirements of various asymmetric services and retains great flexibility.

[0110] Reference signals need to be inserted into both the data channel and the control channel for demodulating the data transmitted in the channel. Figure 7 In the shown example, the reference signal is sent on the first symbol of each resource block, and the channel state information of the remaining symbols can be obtained by methods such as interpolation. Except Figure 7 for the shown scheme, a discrete insertion method similar to the reference signal in LTE can also be adopted, and channel estimation at multiple time-frequency points can be obtained by inserting reference signals on discontinuous symbols and subcarriers.

[0111] In addition, considering that the requirements for the accuracy of channel estimation for the control channel and the data channel are inconsistent, the frequencies of inserting reference signals in the control channel and the data channel can also be different. For example, considering that the control channel requires a higher accuracy rate compared to the data channel, the requirements for the accuracy of channel estimation are also higher. For the control channel, the frequency of inserting reference signals can be increased to ensure the accuracy of channel estimation for the control channel. At the same time, the frequency of inserting reference signals in the data channel can be decreased to obtain a higher spectral efficiency.

[0112] The reference signals transmitted by the base station through the uplink data subframe and the uplink pilot time slot in the special subframe can be used to obtain the channel state information of the uplink channel. Utilizing channel reciprocity, the base station can infer the downlink channel state information based on the uplink channel state information and use this information to complete operations such as precoding. The reference signals in the downlink data channel are used to estimate the equivalent channel after precoding, which is similar to the demodulation reference signals in LTE. Since the in-band hybrid duplex mode can utilize the uplink-downlink channel reciprocity, the downlink physical channel estimation and channel state information feedback in large-scale MIMO technology are greatly simplified, which is beneficial to the implementation of large-scale MIMO technology and high-frequency band technology in 5G.

[0113] In addition, Figure 6 The structure shown is applicable to modulation methods that do not require the insertion of CP, such as FBMC technology, etc. For modulation methods that require CP to reduce inter-symbol interference, such as F-OFDM technology, Figure 6 the structure shown needs to be slightly modified. For example, after adding CP to each symbol, the lengths of the time slot, subframe, and radio frame will change, and the length of CP depends on factors such as the waveform used and the multipath delay to be combated. Note that the frame structure, especially whether CP is inserted in the multi-carrier symbol, does not affect the implementation of the solution provided by the present invention, and the subsequent description of this application will still use Figure 6 the frame structure shown. The bandwidth occupied by each channel can be adjusted according to the actual application scenario. For example, considering that the downlink control channel needs to transmit more signaling compared to the uplink control channel, more bandwidth can be allocated to the downlink control channel while reducing the bandwidth allocated to the uplink control channel.

[0114] Embodiment 2:

[0115] In this embodiment, parameters such as the system frame structure and spectrum structure are the same as those set in Embodiment 1. Different from the cell-specific uplink and downlink configuration of the data channel obtained by the terminal through broadcast messages in Embodiment 1, in order to configure the uplink and downlink communication more flexibly, the uplink and downlink configuration of the subframe can be indicated in the downlink control channel. For example, a possible way is that subframe 0 of each radio frame is used for downlink communication; when it is necessary to switch to uplink communication, an uplink handover indication is sent in the downlink control channel of the subframe before the handover; during the uplink communication process, if it is necessary to switch to downlink communication, a downlink handover indication is sent in the downlink control channel of the subframe before the handover. Figure 9 The figure shows a schematic diagram of flexible configuration of uplink and downlink data communication in the above manner.

[0116] Figure 9 In the figure, subframe 0 is used for downlink communication, and the base station inserts an uplink handover indication in the downlink control channel of subframe 1 to notify the terminal that the next frame of this subframe, that is, subframe 2, is used for uplink and downlink handover. The structure of subframe 2 is similar to that of the special subframe in Figure 8 and is divided into three parts: downlink communication, guard interval, and uplink communication. The guard interval is used to provide protection when switching from downlink communication to uplink communication. The specific structure of subframe 2 can be further indicated in the downlink control channel. Subframes 3, 4, 5, and 6 are all used for uplink communication, and the base station inserts a downlink handover indication in the downlink control channel of subframe 6, and the next frame of this subframe, that is, subframe 7, switches to downlink communication.

[0117] Figure 9 Although the uplink and downlink data communication configuration method shown in the figure introduces a certain amount of signaling overhead (it is necessary to insert uplink and downlink handover indications in the downlink control channel), compared with the TDD mode in LTE, its uplink and downlink communication configuration is more flexible, and the base station can flexibly adjust the uplink and downlink data communication configuration according to the needs of downlink and uplink data communication.

[0118] In order to utilize the channel reciprocity in the TDD mode, it is necessary to ensure that at least one subframe in each radio frame is used for uplink transmission. It can be stipulated that at least one uplink handover indication needs to be transmitted in the downlink control signaling, and ensure that there is a complete subframe for uplink communication.

[0119] Embodiment 3:

[0120] In this embodiment, an example of flexible configuration of the protection band will be given. The parameters such as the system frame structure and the spectrum structure are the same as those in Embodiment 1. In Embodiment 1, the dual-frequency band division structure uses the protection band of the same size between the data channel and the control channel, which is relatively simple and suitable for the low-power small cell scenario. Considering that in most cases, the transmit power of the downlink communication is usually large, while the receive power of the uplink communication is small, the downlink transmission (including the data channel and the control channel) will cause relatively large interference to the uplink reception. The interference caused by the uplink transmission to the downlink reception is relatively small. If a fixed-size protection band is used between sub-bands to prevent leakage interference between sub-bands, although it is simple, leaving too much will cause waste in the case of uplink transmission interfering with downlink reception, and leaving too little is not enough to suppress the adjacent band leakage interference caused by downlink transmission to uplink reception. Therefore, this embodiment proposes that the size of the protection band can be adjusted according to the interference situation on the pre-set basic protection band.

[0121] Figure 10 The figure shows a schematic diagram of the in-band hybrid duplex mode with a protection band inserted in the data channel. Figure 10 In the figure, the downlink special time slot in Subframe 0 and the subsequent special subframes is used for downlink communication, which will interfere with the uplink control channel using the adjacent frequency band. By leaving a part of the frequency band on the side of the data channel close to the uplink control channel as the protection band, the protection band between the downlink data communication channel and the uplink control channel can be expanded, thereby enhancing the protection of the uplink control channel. For example, when transmitting in the downlink special time slots of Subframe 0 and Subframe 1, 5 subcarriers are left untransmitted on the side close to the uplink control channel as the protection band in the data channel. In this way, compared with Figure 8 the structure shown in the figure, the protection band between the downlink data communication and the uplink control channel is expanded to 10 subcarriers, that is, 3 MHz, which can provide better protection for the uplink control channel.

[0122] Similarly, the uplink pilot time slot in Subframe 1 and the subsequent Subframes 2, 3, and 4 are used for uplink transmission, which will be interfered by the downlink control channel in the adjacent frequency band. To reduce this interference, a part of the subcarriers are left as the protection band in the frequency band of the uplink pilot time slot in Subframe 1 and Subframes 2, 3, and 4 close to the downlink control channel. For example, 5 subcarriers are left untransmitted, and the protection band between the downlink control channel and the uplink communication is expanded to 3 MHz, thereby providing better protection for the uplink data communication.

[0123] Although the above method of inserting an additional protection band in the data channel can resist the interference of downlink communication to uplink communication, it will cause a reduction in the effective data frequency band, thereby causing a reduction in the transmission data rate. Figure 11 The figure shows a schematic diagram of the in-band hybrid duplex mode with a protection band inserted in the control channel. Figure 11In this case, by inserting an additional guard band into the control channel, the guard band between downlink communication and uplink communication can be extended, which plays a role in strengthening the protection of uplink communication.

[0124] In addition to Figure 10 , Figure 11 the method of inserting an additional guard band shown above, the guard band can also be extended by combining two methods, that is, a part of the additional guard band is inserted into the data channel and another part of the guard band is inserted into the control channel.

[0125] In addition to the above methods of adding an additional guard band in the data channel or the control channel, the adjustment of the guard band can also be obtained by moving the center frequency point of the corresponding subframe data channel. As Figure 12 shown in the figure is a schematic diagram of the method of adjusting the guard band by adjusting the center frequency point of the data channel. By moving the subframes (subframe 0 and subframe 5) for downlink communication, and the center frequency points of the downlink special time slots for downlink communication in the special subframe, making them closer to the downlink control channel. At this time, the guard band between the subframes for downlink communication in the data channel and the uplink control channel increases, so better protection can be provided for the uplink control channel. At the same time, although the guard band between the subframes for downlink communication in the data channel and the downlink control channel becomes narrower, since the interference between them is not serious, the system performance will not be significantly affected. Similarly, by moving the subframes (subframes 2, 3, 4, 7, 8, 9) for uplink communication and the center frequency points of the uplink pilot time slots in the special subframe, making them closer to the uplink control channel. At this time, the guard band between the downlink control channel and the subframes for uplink communication in the data channel becomes larger, and better protection can be provided for the uplink data channel.

[0126] The method of adjusting the guard band by moving the center frequency point of the data channel can ensure that the data rate is not affected. For example, moving the subframes for downlink communication in the data channel 3 subcarriers towards the downlink control channel. At this time, the guard band between the subframes for downlink communication in the data channel and the uplink control channel is extended to 2.4 MHz, while the total guard band is still 3 MHz. The overhead brought by the guard band remains unchanged, but the protection provided for the uplink control channel is enhanced.

[0127] The guard band pattern (the position and size of the additional guard band or the offset of the center frequency of the data channel) can be stored in the base station and the terminal by means of a lookup table. The base station transmits the guard band pattern through the broadcast channel or the downlink control channel in subframe 0. The terminal determines the bandwidth and position of the control channel and the data channel by receiving the guard band pattern in the broadcast channel or the downlink control channel. The size of the basic guard band and the size of the additional guard band can also be fixed by a predefined method. The terminal directly obtains the bandwidth of the data channel implicitly through the uplink and downlink communication conditions of the data channel and the adjacent band conditions of the control channel, for example Figure 10 Given the uplink and downlink configurations shown, the terminal knows through a predetermined rule that the data channel deducts an additional 5 subcarriers at the edge of the subband close to the downlink control channel in subframe 3, while the subband close to the uplink control channel uses the basic protection band.

[0128] Since the guard band is mainly used to protect the uplink receiving signal from the downlink transmitting signal, the base station can also determine the size of the guard band by measuring the uplink signal receiving strength and the downlink communication out-of-band leakage. The uplink signal receiving strength is mainly determined by the cell size and the distance between the terminal and the base station. Therefore, during the terminal movement, it may be necessary to dynamically adjust the size of the guard band to adapt to the channel changes. Specifically, the base station determines the size of the guard band based on the uplink signal reception situation and notifies the terminal in the broadcast channel or downlink control channel. The terminal learns the uplink and downlink control channel bandwidth, data channel bandwidth and center frequency point location according to the corresponding instructions.

[0129] Embodiment 4:

[0130] This embodiment will provide an example of improving the reliability of the control channel in a duplex communication system with separated control and data in the frequency band. The system frame structure and spectrum structure still use the same settings as in the first embodiment. Using the same frequency band to transmit the control channel will have an adverse effect on a transmission environment with strong frequency selective fading. In order to improve the transmission reliability of the control channel, this embodiment transmits the control signaling by frequency hopping to provide frequency diversity gain for the control channel.

[0131] A better way to transmit control signaling by frequency hopping is as follows Figure 13 As shown in the figure, it can be seen that the uplink and downlink control channel transmissions are switched in units of two subframes (0.2ms), and a guard interval is inserted when the uplink and downlink control channels are switched. This switching can ensure that the uplink control channel goes through different frequency bands, thereby providing frequency diversity for the control channel and improving the control channel's ability to resist fading.

[0132] It should be noted that in the above method of hopping transmission control signaling, the switching protection interval of the uplink and downlink control channels can be flexibly configured. The hopping mode of the control channel can be predefined, or the base station can indicate the hopping mode in the broadcast channel or downlink control channel located in subframe 0, and the terminal can learn the positions of the uplink and downlink control channels through this indication.

[0133] Figure 14 Another way to provide frequency diversity for the control channel is shown, that is, transmitting control signaling within the data channel. Figure 14 In it, the control signaling within the data channel is transmitted on the first few multi-carrier modulation symbols of each subframe. Except Figure 14 For the scheme shown, the control signaling within the data channel can also be continuously transmitted on several middle subcarriers. In addition, the downlink special time slot in the special subframe can also be used to transmit downlink control signaling.

[0134] The control signaling within the data channel is a repetition of the control data of the corresponding subframe control channel, and can also carry additional control signaling about this subframe.

[0135] Figure 13 And Figure 14 The two schemes shown can be combined, that is, inserting control signaling on the data channel while using control channel hopping to provide more reliable protection for the transmission of uplink and downlink control signaling.

[0136] Embodiment 5:

[0137] This embodiment describes the timing and processing method of HARQ in the in-band hybrid duplex mode proposed in this application. In this embodiment, the system frame structure and spectrum structure are the same as those in Embodiment 1.

[0138] For the in-band hybrid duplex mode, the uplink and downlink control channels always exist, thus avoiding the problems of timing chaos and low efficiency existing in the TDD mode in LTE. The downlink HARQ transmission adopts a similar asynchronous method in LTE, that is, only the timing for the terminal to send ACK / NACK signals after receiving a data packet is specified. When the base station receives the ACK / NACK signals sent by the terminal and needs to retransmit the data packet, the HARQ process number in the downlink control channel of the corresponding subframe is used to indicate the data packet received by the terminal corresponding to the current retransmitted data packet. Therefore, it is not necessary to specify the timing when the base station retransmits data for the terminal, that is, the base station can retransmit data in an asynchronous manner. If the time for the terminal to feedback ACK / NACK is specified to be after 0.3 ms of receiving the data packet, then Figure 15 A possible timing of the downlink HARQ is shown.

[0139] Figure 15The first line in [Example] shows the uplink and downlink communication configuration used in this embodiment. In this configuration, subframe 0 and subframe 5 in the data channel are used for downlink transmission, subframe 1 and subframe 6 are special subframes, and the remaining subframes are used for uplink transmission. The symbol P represents downlink data transmission, and the symbol A represents the ACK / NACK feedback of data P. As can be seen from the figure, the ACK / NACK feedback of the data packet occurs 3 subframes after the received data subframe, that is, after 0.3 ms. Taking the ACK / NACK in the second line as an example, the terminal receives the downlink data P1 in subframe 0, and after processing, transmits the corresponding ACK / NACK signal to the base station on the uplink control channel in subframe 4. After processing by the base station, if it is found that the data packet needs to be retransmitted, it will be transmitted in the subframe after subframe 5, and the HARQ process number will be inserted into the corresponding downlink control channel to indicate to the terminal.

[0140] The HARQ feedback modes of different uplink and downlink communication configurations are basically similar, that is, after data is sent in the downlink data communication subframe, the terminal transmits the ACK / NACK signal of the corresponding data packet in the uplink control channel after a specified time ( Figure 15 0.3 ms in the shown example). When the base station retransmits the data packet, the HARQ process number is inserted into the downlink control channel of the corresponding subframe to indicate to the terminal.

[0141] Compared with the downlink HARQ timing of the LTE TDD mode, there is no situation where the uplink control channel resources are insufficient in the in-band hybrid duplex mode proposed in this application. Therefore, technologies such as ACK / NACK binding or ACK / NACK multiplexing are not required, which makes the downlink HARQ feedback timely and simple.

[0142] The uplink HARQ timing adopts a mode similar to LTE, that is, after the downlink sends the uplink grant signaling or the uplink ACK / NACK signal, the uplink data packet is sent on the data channel of an available uplink subframe after a specified time. After the base station receives the uplink data packet, the uplink grant signal or the uplink ACK / NACK signal is sent on the downlink control channel of the subframe after a specified time. Figure 16 The figure shows a possible uplink HARQ timing diagram. Among them, it is stipulated that the base station gives feedback 0.3 ms after receiving the data, and the terminal looks for an available uplink subframe to send data 0.3 ms after receiving the uplink grant signaling or ACK / NACK.

[0143] Figure 16 In [Example], P represents the uplink data packet, which is sent using the uplink data channel, and G / H represents the uplink grant or ACK / NACK signal. Figure 16The first line in the figure shows the uplink and downlink data communication configuration used in this embodiment. Subframe 0 and subframe 5 are used for downlink data communication, subframes 1 and 6 are special subframes, and the remaining subframes are used for uplink data communication. Taking the HARQ timing shown in the second line of the figure as an example, the terminal sends uplink data in subframe 2. After receiving and processing, the base station sends an uplink grant or ACK / NACK signal on the downlink control channel in subframe 6. Since the subframes separated by 0.3 ms are downlink data communication subframes, the terminal performs uplink data communication in subframe 2 of the second radio frame.

[0144] Figure 16 In the HARQ timing shown in the third line of the figure, although the base station sends an uplink grant or ACK / NACK signal in subframe 7 of the first radio frame, the subframe 0.3 ms later is used for downlink data communication, and the first uplink data subframe 0.3 ms later, that is, subframe 2 of the second radio frame, has been used for the HARQ feedback timing. Therefore, the terminal performs uplink data communication in subframe 3 of the second radio frame.

[0145] It can be seen that compared with the uplink HARQ timing in the TDD mode of LTE, Figure 16 in the uplink HARQ timing shown, the base station does not need to wait for an available downlink data communication subframe to send an uplink grant signal or ACK / NACK signal on the downlink control channel. When the proportion of downlink data communication is small, the HARQ waiting time can be shortened. For example Figure 16 in the example shown, the round-trip time (RTT) is 1.0 ms, that is, the length of one radio frame, which is lower than the round-trip time of the LTE TDD mode with the same uplink and downlink data communication configuration, and can meet the air interface delay requirement of 5G of 1 ms.

[0146] It should be noted that the delay (0.3 ms) between receiving data and sending ACK / NACK signals selected in this embodiment is only an example, and the size of this delay needs to be determined according to the device processing capacity and the actual frame structure in the actual system.

[0147] Embodiment Six:

[0148] This embodiment will give the access and communication processes of the terminal and the base station adopting the in-band hybrid duplex mode provided by this application. Specifically, it includes:

[0149] The terminal completes the cell search process by receiving the synchronization channel and the broadcast channel at the center position of the second sub-band, and obtains the system configuration information by reading the physical broadcast channel. Among them, the time-frequency positions of the synchronization channel and the broadcast channel are pre-configured in the frame structure; the system configuration information includes at least one of the following information: system bandwidth, uplink and downlink communication configuration, guard band configuration, control channel hopping configuration;

[0150] The terminal obtains the central frequency position and bandwidth of the uplink and downlink control channels, the central frequency position and bandwidth of the service channels, and the uplink and downlink data communication configuration through the system configuration information in the physical broadcast channel;

[0151] The terminal obtains the system configuration information carried on the downlink data channel through the downlink control channel, and initiates and completes uplink access according to the configuration information;

[0152] The terminal communicates with the base station according to the agreed uplink and downlink communication configurations.

[0153] The system frame structure and spectrum structure of this embodiment are the same as those in the first embodiment. The primary synchronization signal (PSS), the secondary synchronization signal (SSS) and the physical broadcast channel (PBCH) are all transmitted in the downlink special time slot of the downlink data channel and the special subframe adjacent thereto, and the physical random access channel (PRACH) is transmitted in the uplink pilot time slot of the special subframe, such as Figure 17 shown. Figure 17 This is a schematic diagram of a preferred synchronization and broadcast channel configuration structure for this application, wherein PSS and SSS are used for cell search, and PBCH contains system information including system bandwidth, uplink and downlink transmission structure, etc. After the terminal is turned on, the cell search is completed by searching and detecting PSS and SSS, system synchronization is completed, and the cell ID is obtained. After that, the terminal reads the PBCH to obtain system information such as system bandwidth, system frame number, and base station antenna configuration. In addition, since the intra-band hybrid duplex mode uses a time division method to distinguish uplink and downlink data communications during data communication, the terminal also needs to obtain the uplink and downlink data communication configuration. This information can be implicitly informed to the terminal through the position of the special subframe, that is, the base station only needs to broadcast the position of the special subframe in the PBCH, and the terminal infers the uplink and downlink data communication configuration based on this information. The special subframe position is informed to the terminal by means of a lookup table, that is, the special subframe position is stored in a lookup table known to both the base station and the terminal, and the base station only sends the index of the corresponding special subframe position in the PBCH. Through this index, the terminal learns the position of the special subframe, the duration of the downlink special time slot, the guard interval and the uplink pilot time slot in the special subframe, and obtains the uplink and downlink communication configuration. Figure 17 Taking the example shown as an example, the terminal learns from the special subframe position index that subframe 1 and subframe 6 are special subframes, and learns from the corresponding mode that subframe 1 and subframe 5 are used for downlink data communication, while subframes 2, 3, 4, 7, 8, and 9 are used for uplink communication.

[0154] For the in-band hybrid duplex mode proposed in this application, it is also necessary to notify the terminal of the mode of the guard band between the control channel and the data channel, that is, whether to use the guard band with the same bandwidth for different subframes, and the used guard band mode. Similar to the special subframe position information, the guard band mode is stored in both the base station and the terminal in the form of a look-up table. The base station only needs to broadcast the index of the corresponding guard band mode in the look-up table on the PBCH. Taking Figure 17 the example shown as an example, the terminal knows through the guard band mode index that the system uses the guard band with the same bandwidth, and then infers that the downlink control channel and the uplink control channel of the system are respectively located at 15 subcarriers at the edges of the system frequency band.

[0155] After the terminal knows the system bandwidth and the guard band bandwidth, it can infer the data channel bandwidth and the control channel position, read the downlink control channel, and complete the uplink access by reading other system configuration information (such as random access configuration information, etc.) included in the dynamic broadcast channel in the downlink data channel. After that, it communicates with the base station according to the base station scheduling information (such as the flexibly configured uplink and downlink configuration information) or the agreed uplink and downlink communication configuration.

[0156] For the case of flexible configuration of uplink and downlink communication shown in Embodiment 2, it is necessary to reserve time-frequency resources for the uplink physical random access channel. To avoid additional signaling overhead, before the terminal completes access, the uplink and downlink communication configuration pre-specified in the PBCH can be used for communication.

[0157] Corresponding to the above method, this application also provides a base station, and its preferred composition structure is as Figure 18 shown. The base station includes: a control transmission module and a data transmission module, where:

[0158] The control transmission module is used to transmit one of the uplink control channel and the downlink control channel in the first sub-band and the third sub-band of the available continuous frequency band respectively, and transmit control channels in different directions in the first sub-band and the third sub-band at the same time;

[0159] The data transmission module is used to transmit uplink data and downlink data in the second sub-band of the available continuous frequency band in a time-division multiplexing manner;

[0160] Among them, the first sub-band and the third sub-band are located at both ends of the available continuous frequency band.

[0161] Corresponding to the above method, this application also provides a terminal, and its preferred composition structure is as Figure 19 shown. The terminal includes: a cell search module, a configuration information acquisition module, an access module, and a communication module, where:

[0162] The cell search module is used to complete the cell search process by receiving the synchronization channel and the broadcast channel at the center position of the second sub-band, and to obtain the system configuration information by reading the physical broadcast channel. The time-frequency positions of the synchronization channel and the broadcast channel are pre-configured in the frame structure. The system configuration information includes at least one of the following information: system bandwidth, uplink and downlink communication configuration, guard band configuration, control channel hopping configuration;

[0163] The configuration information acquisition module is used to obtain the center frequency point position and bandwidth of the uplink and downlink control channels, the center frequency point position and bandwidth of the traffic channel, and the uplink and downlink data communication configuration through the system configuration information in the physical broadcast channel;

[0164] The access module is used to obtain the system configuration information carried on the downlink data channel through the downlink control channel, and initiate and complete the uplink access according to the configuration information;

[0165] The communication module is used to communicate with the base station according to the agreed uplink and downlink communication configuration.

[0166] The above are only the preferred embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present application shall be included within the scope of protection of the present application.

Claims

1. A method performed by a base station in a wireless communication system, characterized in that, comprising: sending a downlink control channel to a terminal in a first sub-band of an available continuous frequency band; when sending the downlink control channel, receiving an uplink control channel from the terminal in a third sub-band of the available continuous frequency band; in a second sub-band of the available continuous frequency band, sending downlink data to the terminal on a data channel and receiving uplink data from the terminal on the data channel in a time-division multiplexing manner; wherein, the first sub-band and the third sub-band are located at both ends of the available continuous frequency band.

2. The method according to claim 1, characterized in that: there is a first guard band between the first sub-band and the second sub-band, and there is a second guard band between the second sub-band and the third sub-band, and no signal is transmitted in the first guard band and the second guard band.

3. The method according to claim 2, characterized in that: the size of the first guard band or the second guard band is set according to the interference level between adjacent sub-bands and the out-of-band leakage suppression method adopted.

4. The method according to claim 2, characterized in that, the method further comprises: adjusting the size of the first guard band and the second guard band by at least one of the following: inserting an additional guard band in at least one sub-band, wherein the adjusted parameters include: the position and size of the additional guard band inserted in the downlink and uplink control channels and / or data channels; adjusting the center frequency of at least one sub-frame in the data channel on the second sub-band, and the adjusted parameters include: the offset of the data channel center frequency.

5. The method according to claim 4, characterized in that: the method further comprises: dynamically adjusting the guard band mode according to the uplink data reception signal strength, and indicating the guard band mode currently used by the terminal in a predefined manner or through a broadcast channel or the downlink control channel.

6. The method according to claim 4, characterized in that: the method further comprises: storing the correspondence between the guard band mode and its index in a look-up table, and indicating the guard band mode currently used by the terminal by indicating the index of the corresponding mode to the terminal.

7. The method according to claim 1, characterized in that: the method further comprises: notifying the terminal of the positions and bandwidths of the respective sub-bands in the available continuous frequency band, and the uplink and downlink configurations of the data channel, and communicating with the terminal according to the agreed configuration.

8. The method according to claim 1, characterized in that: the downlink control channel is used to transmit downlink control signaling, and the downlink control signaling at least includes one of the following information: resource allocation information, coding and modulation information, hybrid automatic repeat request acknowledgement / non-acknowledgement information, uplink transmission authorization, uplink transmission power control indication; the uplink control channel is used to receive uplink control signaling, and the uplink control signaling at least includes one of the following information: scheduling request, hybrid automatic repeat request acknowledgement / non-acknowledgement information, channel state information; The second sub-band is used for receiving uplink data and transmitting downlink data, and is also used for transmitting at least one of the following channels: a synchronization channel, a broadcast channel for transmitting system information, and an uplink random access channel.

9. The method according to claim 1, wherein: The method further includes: sending an uplink handover indication and / or a downlink handover indication on a downlink control channel to change the transmission direction of subframes in a data channel.

10. The method according to claim 9, wherein: The method further includes: sending an uplink handover indication at least once in the downlink control channel of each radio frame, and at least one subframe in the data channel is used for uplink data communication.

11. The method according to claim 1, wherein: The method further includes: inserting a guard interval when the channel switches from downlink transmission to uplink transmission, and no signal is transmitted in the guard interval.

12. The method according to claim 11, wherein: The method further includes: inserting a special subframe when switching from downlink transmission to uplink transmission; The special subframe includes: a downlink special time slot, a guard interval, and an uplink pilot time slot, where: The downlink special time slot is used for downlink communication, and the transmitted content includes at least one of the following information: a downlink data channel, a physical synchronization channel, and a physical broadcast channel; The uplink pilot time slot is used to carry a sounding pilot signal; No signal is transmitted in the guard interval.

13. The method according to claim 1, wherein: A filter-based or filter bank-based single-carrier or multi-carrier modulation method is used on each sub-band; The filter-based or filter bank-based single-carrier or multi-carrier modulation method includes at least one of the following modulation methods: filter bank multi-carrier FBMC based on subcarrier filtering, Filtered-OFDM based on band filtering, and single-carrier filter bank multi-carrier SC-FBMC based on band filtering.

14. The method according to claim 1, wherein: The first subframe of each radio frame is used for downlink transmission.

15. The method according to claim 1, wherein: The method further includes: transmitting control signaling in a data channel within the second sub-band, and informing the terminal whether to transmit control signaling in the data channel within the second sub-band through a downlink control channel within the first sub-band or a broadcast channel within the second sub-band; wherein, the method of transmitting control signaling in the data channel within the second sub-band includes at least one of the following methods: using a part of the time-frequency resources of the downlink subframe in the data channel to transmit the signaling in the downlink control channel, and using a part of the time-frequency resources of the uplink subframe in the data channel to transmit the signaling in the uplink control channel.

16. A method performed by a terminal in a wireless communication system, wherein, including: Receiving a downlink control channel from a base station in a first sub-band of an available continuous frequency band; When receiving the downlink control channel, sending an uplink control channel to the base station in a third sub-band of the available continuous frequency band; In the second sub - band of the available continuous frequency band, receive downlink data from the base station on the data channel and send uplink data to the base station on the data channel in a time - division multiplexing manner; Among them, the first sub - band and the third sub - band are located at both ends of the available continuous frequency band.

17. The method according to claim 16, characterized in that, further comprising: Complete the cell search process by receiving the synchronization channel and the broadcast channel at the center position of the second sub - band, and obtain the first system configuration information by reading the broadcast channel; Obtain the center frequency point position and bandwidth of the uplink and downlink control channels, the center frequency point position and bandwidth of the data channel, and the uplink and downlink configurations through the first system configuration information in the broadcast channel; Obtain the second system configuration information of the downlink sub - frame carried on the data channel through the downlink control channel, and initiate uplink access according to the second system configuration information; Communicate with the base station according to the agreed - upon uplink and downlink configurations; Among them, the time - frequency positions of the synchronization channel and the broadcast channel are pre - configured in the frame structure; the first system configuration information and / or the second system configuration information includes at least one of the following information: system bandwidth, uplink and downlink configurations, guard band configurations, control channel hopping configurations.

18. The method according to claim 17, characterized in that, further comprising: Obtain the uplink and downlink configurations, guard band configurations, and control channel hopping configurations based on a predetermined look - up table by receiving the index required for the look - up table from the base station.

19. The method according to claim 17, characterized in that: Determine the position of the uplink and downlink hybrid automatic repeat request HARQ acknowledgement / non - acknowledgement ACK / NACK according to the sub - frame position for uplink and downlink data communication in the data channel.

20. A base station, characterized in that, comprising: A module for sending a downlink control channel to the terminal in the first sub - band of the available continuous frequency band; A module for receiving an uplink control channel from the terminal in the third sub - band of the available continuous frequency band when sending the downlink control channel; A module for sending downlink data to the terminal on the data channel and receiving uplink data from the terminal on the data channel in a time - division multiplexing manner in the second sub - band of the available continuous frequency band; Among them, the first sub - band and the third sub - band are located at both ends of the available continuous frequency band.

21. The base station according to claim 20, characterized in that: There is a first guard band between the first sub - band and the second sub - band, and a second guard band between the second sub - band and the third sub - band, and no signal is transmitted in the first guard band and the second guard band.

22. The base station according to claim 21, characterized in that: The size of the first guard band or the second guard band is set according to the interference level between adjacent sub - bands and the out - of - band leakage suppression method adopted.

23. The base station according to claim 21, characterized in that: The base station further comprises a module for adjusting the size of the first guard band and the second guard band by at least one of the following: Insert additional guard bands within at least one sub - band, where the adjusted parameters include: the position and size of the additional guard bands inserted within the downlink and uplink control channels and / or data channels; Adjust the center frequency points of at least one sub - frame in the data channel on the second sub - band, and the adjusted parameters include: the offset of the data channel center frequency point.

24. The base station according to claim 23, characterized in that: The base station further includes a module for dynamically adjusting the guard band mode according to the received signal strength of the uplink data, and indicating the currently used guard band mode for the terminal through a predefined method, or a broadcast channel, or the downlink control channel.

25. The base station according to claim 24, characterized in that: The base station further includes a module for storing the correspondence between the guard band mode and its index in a look - up table, and indicating the currently used guard band mode for the terminal by indicating the index of the corresponding mode to the terminal.

26. The base station according to claim 20, characterized in that: The base station further includes a module for notifying the terminal of the positions and bandwidths of each sub - band within the available continuous frequency band, and the uplink and downlink configurations of the data channel, and communicating with the terminal according to the agreed - upon configuration.

27. The base station according to claim 20, characterized in that: The downlink control channel is used to transmit downlink control signaling, and the downlink control signaling at least includes one of the following information: resource allocation information, coding and modulation information, hybrid automatic repeat request acknowledgement / non - acknowledgement information, uplink transmission authorization, uplink transmission power control indication; The uplink control channel is used to receive uplink control signaling, and the uplink control signaling at least includes one of the following information: scheduling request, hybrid automatic repeat request acknowledgement / non - acknowledgement information, channel state information; The second sub - band is used to receive uplink data and transmit downlink data, and is also used to transmit at least one of the following channels: synchronization channel, broadcast channel for transmitting system information, and uplink random access channel.

28. The base station according to claim 20, characterized in that: The base station further includes a module for sending an uplink handover indication and / or a downlink handover indication in the downlink control channel to change the transmission direction of the sub - frames in the data channel.

29. The base station according to claim 28, characterized in that: The base station further includes a module for sending an uplink handover indication at least once in the downlink control channel of each radio frame, and at least one sub - frame in the data channel is used for uplink data communication.

30. The base station according to claim 20, characterized in that: The base station further includes a module for inserting a guard interval when the channel switches from downlink transmission to uplink transmission, and no signal is transmitted in the guard interval.

31. The base station according to claim 30, characterized in that: The base station further includes a module for inserting a special sub - frame when the downlink transmission switches to uplink transmission; The special sub - frame includes: a downlink special time slot, a guard interval, and an uplink pilot time slot, where: The downlink special time slot is used for downlink communication, and the transmitted content includes at least one of the following information: downlink data channel, physical synchronization channel, physical broadcast channel; The uplink pilot time slot is used to carry sounding pilot signals; No signals are transmitted in the guard interval.

32. The base station according to claim 20, characterized in that: A single-carrier or multi-carrier modulation method based on a filter or a filter bank is used in each sub-band; The single-carrier or multi-carrier modulation method based on a filter or a filter bank includes at least one of the following modulation methods: Filter Bank Multi-Carrier (FBMC) based on sub-carrier filtering, Filtered Orthogonal Frequency Division Multiplexing (Filtered-OFDM) based on band filtering, and Single-Carrier Filter Bank Multi-Carrier (SC-FBMC) based on band filtering.

33. The base station according to claim 20, characterized in that: The first sub-frame of each radio frame is used for downlink transmission.

34. The base station according to claim 20, characterized in that: The base station further includes: a module for transmitting control signaling in a data channel within a second sub-band, and informing a terminal whether to transmit control signaling in the data channel within the second sub-band through a downlink control channel within a first sub-band or a broadcast channel within the second sub-band; wherein, the method of transmitting control signaling in the data channel within the second sub-band includes at least one of the following methods: using a part of the time-frequency resources of a downlink sub-frame within the data channel to transmit signaling within a downlink control channel, using a part of the time-frequency resources of an uplink sub-frame within the data channel to transmit signaling within an uplink control channel.

35. A terminal, characterized in that, comprising: a module for receiving a downlink control channel from a base station in a first sub-band of an available continuous frequency band; a module for transmitting a control channel to the base station in a third sub-band of the available continuous frequency band when receiving the downlink control channel; a module for receiving downlink data from the base station on a data channel and transmitting uplink data to the base station on the data channel in a time-division multiplexing manner in a second sub-band of the available continuous frequency band; wherein, the first sub-band and the third sub-band are located at both ends of the available continuous frequency band.

36. The terminal according to claim 35, characterized in that, further comprising: a module for completing a cell search process by receiving a synchronization channel and a broadcast channel at the center position of a second sub-band, and obtaining first system configuration information by reading the broadcast channel; a module for obtaining the center frequency point position and bandwidth of an uplink and downlink control channel, the center frequency point position and bandwidth of a data channel, and uplink and downlink configurations through first system configuration information within a broadcast channel; a module for obtaining second system configuration information carried in a downlink sub-frame of a data channel through a downlink control channel, and initiating an uplink access according to the second system configuration information; a module for communicating with the base station according to a predefined uplink and downlink configuration; wherein, the time-frequency position of the synchronization channel and the time-frequency position of the broadcast channel are pre-configured in a frame structure; the first system configuration information and / or the second system configuration information includes at least one of the following information: system bandwidth, uplink and downlink configuration, guard band configuration, control channel hopping configuration.

37. The terminal according to claim 36, characterized in that, further comprising: A module for obtaining the uplink and downlink configuration, guard band configuration, and control channel hopping configuration based on a predetermined look-up table by receiving the index required for the look-up table from a base station.

38. The terminal according to claim 36, wherein: A module for determining the position of an uplink and downlink hybrid automatic repeat request HARQ acknowledgement / non-acknowledgement ACK / NACK according to the subframe position for uplink and downlink data communication in a data channel.

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