CN101166070A - Frame structure for shared spectrum between broadcast TV signal and telecommunication signals - Google Patents

Abstract

A frame structure in which broadcast television signals and telecommunication signals share spectrum, which includes a mixed frame composed of telecommunication periods and broadcast periods, wherein the telecommunication periods are mainly used to transmit real-time telecommunication services, and the frame structure also includes only telecommunication periods A certain number of telecommunication frames and a certain number of mixed frames form a superframe with a fixed time length, and the mixed frames are periodically distributed in the superframe, and each mixed frame in the superframe provides a set of broadcast program channels , the superframe transmits all broadcast programs in turn through the broadcast program channel group provided by all the mixed frames contained in it, so that the quality of real-time telecommunications services can be guaranteed, and the spectrum of broadcast TV signals and telecommunication signals can be realized shared.

Description

Frame structure for shared spectrum between broadcast television signal and telecommunication signal

technical field

The invention relates to a frame structure in which broadcast television signals and telecommunication signals share spectrum.

Background technique

The radio and television network and the telecommunication network usually work independently on different frequency bands. The future communication system, the integration of the three networks of the radio and television network, the telecommunication network and the computer network, has been recognized as a very important development direction, so many R&D personnel have carried out Related technology research, in order to realize the integration of broadcast TV network and telecommunication cellular network in the part of wireless transmission. If you want to integrate the radio and television network and the telecommunication network into a unified whole, the air interface design needs to break the restriction that the two existing networks use independent frequency bands, so that the radio and television network and the telecommunication network can share the same A radio resource that enables a user's receiver to receive broadcast television signals and telecommunication data signals on the same frequency band.

In comparison, frequency division multiplexing is a multiplexing method that is easier to implement. However, if frequency division multiplexing is used to share wireless resources between the high-power transmitting stations of the radio and television network and the low-power transmitting stations of the telecommunication network, due to the large power difference between the two transmitting stations, the high-power broadcast and television signals It will cause strong interference to the low-power telecommunication digital signal. In order to suppress this interference and maintain the performance of the telecommunication network, it is necessary to reserve a large space between the high-power broadcast TV signal and the low-power telecommunication digital signal. This will lead to a significant waste of spectrum resources. With the rapid development of services such as wireless Internet access and mobile video, the demand for spectrum resources is getting stronger and stronger. Scarce spectrum resources have become more and more precious. Therefore, , using frequency division multiplexing to make it difficult to effectively avoid the waste of spectrum resources in the shared spectrum of broadcast television networks and telecommunication networks.

Furthermore, if time-division multiplexing is adopted, for example, if simply borrowing the frame structure of the current wireless communication system, the wireless frame of multi-network integration is also simply used using a telecommunication frame similar to a telecommunication system and a broadcasting system similar to a broadcasting system. Frame, that is, the wireless frame structure is shown in Figure 1, which is composed of fixed-length broadcast wireless frames and telecommunication wireless frames. Then, since the broadcast frame is inserted between two adjacent telecommunication frames, the structure of the original telecommunication frame is destroyed. The transmission cycle will have an extremely adverse impact on the real-time business of the telecommunication system, making it difficult to guarantee the communication quality requirements such as user plane delay. This will inevitably cause a temporary interruption of telecommunication communication due to the insertion of broadcast wireless frames. If in order to ensure telecommunication The delay requirement of real-time services and the use of a small radio frame length will make the switching between the broadcast radio frame and the telecom radio frame very frequent, and each switching will increase the overhead of the guard time slot, resulting in a decrease in spectral efficiency. loss.

Therefore, how to solve the shortcomings of the prior art to realize the shared frequency spectrum of the broadcast television signal and the telecommunication signal has become an urgent technical problem to be solved by those skilled in the art.

Contents of the invention

The purpose of the present invention is to provide a frame structure in which broadcast television signals and telecommunication signals share frequency spectrum, so as to realize the sharing of frequency spectrum resources and the improvement of spectrum utilization rate by broadcast television signals and telecommunication signals without affecting the real-time services of telecommunication.

In order to achieve the above object, the present invention provides a frame structure in which broadcast television signals and telecommunication signals share frequency spectrum, which includes: a mixed frame composed of telecommunication periods and broadcast periods.

Wherein, the broadcast period includes a broadcast period subframe, and the telecommunication period is mainly used for transmitting real-time telecommunication services, and the telecommunication period includes: a preamble/synchronization channel, one or more telecommunication downlink subframes, one or more Telecom uplink subframe, in addition, the frame structure of the shared frequency spectrum of the broadcast television signal and the telecommunication signal also includes a telecommunication frame consisting only of telecommunication periods, and the time length of the telecommunication frame is equal to that of the hybrid frame, and the telecommunication frame and The mixed frame forms a superframe according to a preset number ratio, the mixed frame is periodically distributed in the superframe, the superframe has a fixed time length, and the broadcast period of each mixed frame in the superframe is to provide a set of A time period of a broadcasting program channel, the superframe is a frame in which all broadcasting programs are sent in turn once in turn through the broadcasting program channel group provided by all the mixed frames contained therein.

To sum up, the frame structure of the shared frequency spectrum of broadcast television signals and telecommunication signals in the present invention forms a mixed frame by combining the telecommunication period and the radio and television period, and realizes the spectrum sharing between the broadcast and television signals and the telecommunication signals without affecting the real-time telecommunications services. Resource sharing and improved spectrum utilization.

Description of drawings

FIG. 1 is a schematic diagram of an existing wireless frame structure.

Fig. 2 is a schematic diagram of the frame structure of the frequency spectrum shared by the broadcast television signal and the telecommunication signal according to the present invention.

Fig. 3 is a schematic structural diagram of a telecommunication frame of a frame structure in which a broadcast television signal and a telecommunication signal share a frequency spectrum according to the present invention.

Fig. 4 is a schematic structural diagram of a mixed frame of a frame structure in which a broadcast television signal and a telecommunication signal share a frequency spectrum according to the present invention.

FIG. 5 is a schematic structural diagram of a superframe of a frame structure of a shared frequency spectrum of a broadcast television signal and a telecommunication signal according to the present invention.

Detailed ways

The frame structure of the shared frequency spectrum of the broadcast television signal and the telecommunication signal of the present invention is shown in Figure 2, which includes: a telecommunication frame and a mixed frame, and the time length T of each telecommunication frame and each mixed frame is all equal, and the time length can be determined by The system is configured and selected from a series of pre-defined values according to the actual needs. In order to meet the requirements of the real-time telecommunications service user plane delay, usually the basic time length can be taken as 5ms. It should be noted that in order to simplify the diagram, Fig. 2 only shows two mixed frames and one telecommunication frame, but the actual application is not limited to this figure, so it will be explained here.

The structure of the telecommunication frame is shown in Figure 3, which includes two periods: a telecommunication downlink period and a telecommunication uplink period, wherein the telecommunication downlink period is composed of a leading/synchronization channel and several telecommunication downlink subframes, in the leading/synchronizing channel , by sending a sequence containing the information predicted by the receiving end to support the synchronization of the receiver, and can provide some basic parameter information about the system bandwidth, cell identification number, etc., each telecom downlink subframe can be based on various business The required characteristics, the characteristics of various channel scenarios, and the capabilities of various user terminals adopt different signal multiplexing structures such as data and pilots. Some basic telecom downlink subframes can include diversity subframes to ensure transmission robustness Frames, AMC subframes that use link adaptation to improve throughput when the delay requirement is not high, MIMO subframes that improve throughput when the receiver supports multi-antenna transmission, improve cell boundary signal quality and The spatial beam subframe used when it is strong, and the multicast subframe supporting the telecom multicast service, etc. The telecom uplink period is composed of several telecom uplink subframes. Each telecom uplink subframe can independently realize channel estimation and data equalization in this subframe. Some time-frequency block resources in the telecom uplink period can be configured as uplink competition as required. channel to support user random access, bandwidth request, and cell switching. The allocation of these resources is controlled by the signaling contained in the telecommunications downlink subframe. Due to the air transmission delay and wireless signal attenuation characteristics, etc., for To overcome the influence of mutual interference between the downlink wireless signal and the uplink wireless signal in time division multiplexing, when switching from the telecom downlink period to the telecom uplink period, a downlink-uplink transition gap (Downlink-Uplink transition Gap, DUG) is inserted; The uplink period is switched to the telecommunications downlink period, and an uplink-downlink transition Gap (UDG) is inserted.

The structure of the hybrid frame is shown in Figure 4. The hybrid frame includes three periods: the telecom downlink period, the telecom uplink period and the broadcast period, wherein the telecom downlink period and the telecom uplink period are mainly used for transmission delay requirements Necessary telecommunication real-time services, while non-real-time services are mainly allocated for transmission within telecommunication frames. It should be noted that the telecommunication downlink period can also be used to transmit non-real-time telecommunication services, rather than being limited to the transmission of real-time telecommunication services. For example, in When no real-time telecommunication services need to be transmitted, non-real-time services can be transmitted during the telecommunication period. Usually, the number J of telecommunication downlink subframes in a mixed frame is generally smaller than the number N of telecommunication downlink subframes in a telecommunication subframe; the number of telecommunication uplink subframes in a mixed frame The number K of frames is generally smaller than the number L of telecommunication uplink subframes in a telecommunication subframe. Since the structure of the telecommunication downlink period and the telecommunication uplink period is the same as the structure of the telecommunication downlink period in the telecommunication frame, no further details are given here. The broadcast period includes several Broadcast subframes are used to transmit a large number of radio and television signals in a large coverage area. Usually, a larger FFT and cyclic prefix are used to combat strong frequency selectivity and large multipath extension. Each broadcast subframe should have a certain The multiplexing mode of data and pilot signals supports independent channel estimation and signal equalization in this subframe. Similarly, in the mixed frame, the telecom uplink period is switched from the telecom downlink period to the telecom uplink period, and a guard time slot DUG is inserted. , at the same time, in view of the large difference in power between the large-coverage base station of the broadcast network and the cellular base station of the telecommunication network, and the signal transmission delay between the user terminal and the user terminal is also very different, so when switching from the telecom uplink period to the broadcast period, A Cellular-Broadcast transition Gap (CBG) is inserted to switch from the broadcast period to the telecom downlink period, and a Broadcast-Cellular transition Gap (BCG) is inserted.

In addition, in the frame structure of the frequency spectrum shared by the broadcast television signal and the telecommunication signal, n mixed frames and (S-1)n telecommunication frames form a superframe, and the structure of the superframe is as shown in Figure 5. A superframe The total length of each frame is nS times the length of each frame. In a superframe, there are S-1 telecommunication frames between adjacent two mixed frames, and the broadcast period in each mixed frame has M broadcast subframes , can be used to transmit a group of broadcast programs, every time a superframe passes through, the nM broadcast subframes in the n mixed frames will send all the broadcast programs in turn according to the set order, and the broadcast receiver is watching a broadcast program , only need to receive broadcast signals at a fixed time position in each superframe, and can be in power-saving mode at other times. For telecom real-time service users, resources in each frame can be continuously used, including telecom frames and mixed The resources allocated in the telecommunication period in the frame are used to transmit its real-time service data, so that the user plane delay can be well guaranteed within the required range without being affected by broadcast signal transmission. For non-real-time telecommunication Service users can mainly use the resources allocated in each telecommunication frame to transmit their non-real-time service data. The receivers of these users can only work during the transmission of telecommunication frames, and can enter the section during the transmission of mixed frames. electric mode.

The number and parameters of telecommunication frames and mixed frames in each superframe can be properly configured by the system, and the position of mixed frames can start from frame k in a superframe, where k is an integer not less than 1, and each mixed frame It can be evenly distributed in the superframe according to a certain periodical rule, so as to minimize the impact of broadcast service insertion on telecommunication services, and at the same time facilitate broadcast receivers to search and locate broadcast signals. In addition, in the real-time Under the premise of business requirements, it is possible to increase the length of the broadcast period in the mixed frame as much as possible, so that more broadcast signals can be transmitted in a mixed frame, thereby reducing the number of mixed frames in the super frame, thereby reducing the transmission due to telecommunication signals and Resource overheads such as guard time slots consumed by broadcast signal switching.

To sum up, the frame structure of the shared frequency spectrum of broadcast television signals and telecommunication signals of the present invention forms a mixed frame by combining the telecommunication period and the broadcast period, so that the pairing of the broadcast television signal and the telecommunication signal can be realized without affecting the real-time service of telecommunication. Spectrum resources are shared, and spectrum utilization is improved.

Claims (11)

1. A frame structure in which a broadcast television signal and a telecommunication signal share spectrum, characterized in that it comprises: a mixed frame composed of a telecommunication period and a broadcast period. 2. The frame structure in which broadcast television signals and telecommunication signals share frequency spectrum according to claim 1, characterized in that: the telecommunication time period is a time period for transmitting real-time telecommunication services. 3. The frame structure of broadcast television signal and telecommunication signal shared frequency spectrum as claimed in claim 1 or 2, it is characterized in that comprising in described telecommunication period: preamble/sync channel; Telecom downlink subframe; Telecom uplink subframe. 4. The frame structure in which broadcast television signals and telecommunication signals share a frequency spectrum according to claim 1, wherein the broadcast period is a period during which broadcast television services are transmitted. 5. The frame structure of shared frequency spectrum between broadcast television signals and telecommunication signals according to claim 1 or 4, further comprising: the broadcast period includes one or more broadcast period subframes. 6. The frame structure of shared frequency spectrum of broadcast television signals and telecommunication signals according to claim 1, further comprising: a telecommunication frame composed only of telecommunication periods. 7. The frame structure in which broadcast television signals and telecommunication signals share frequency spectrum according to claim 6, characterized in that: the time length of the telecommunication frame is equal to that of the hybrid frame. 8. The frame structure in which broadcast television signals and telecommunication signals share frequency spectrum according to claim 6 or 7, characterized in that: the telecommunication frame and the mixed frame form a superframe according to a preset number ratio. 9. The frame structure in which broadcast television signals and telecommunication signals share frequency spectrum according to claim 8, wherein the superframe has a fixed time length. 10. The frame structure of broadcast television signal and telecommunication signal sharing frequency spectrum as claimed in claim 8, characterized in that: the broadcast period of each mixed frame in the superframe is a period for providing a group of broadcast program channels, the A superframe is a frame in which all broadcast programs are sequentially transmitted once through the broadcast program channel group provided by all the mixed frames contained therein. 11. The frame structure of shared frequency spectrum of broadcast TV signal and telecommunication signal according to claim 8, characterized in that: mixed frames are periodically distributed in the super frame.

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