A kind of dispatching method of upstream service of TDD communication system
Technical field
The present invention relates to wireless communication field, the dispatching method of especially a kind of TDD (Time DivisionDuplex, time division duplex) communication system uplink service.
Background technology
TTI (Transmission Time Interval, Transmission Time Interval) be a basic parameter of air interface, the propagation delay time of air interface, to retransmit the gain of time delay, time diversity, link circuit self-adapting gain, multi-user diversity (scheduling) gain etc. automatically directly big or small relevant with the values of TTI.TTI reduces, and the propagation delay time of air interface and the automatic time delay of retransmitting reduce, and the link dynamic adaptable strengthens, and it is big that the multi-user diversity dispatching flexibility becomes, and simultaneously, also can cause interweaving of air interface to be gained and reduce, and the expense of controlling links increases.
At present, the 3G technology standard 3GPP of mechanism (3rd Generation PartnershipProject, third generation partner program) technical report 25.814 that provides " physical layer (Physical layer aspects for evolvedUniversal Terrestrial Radio Access (UTRA) (Release7)) that the land wireless universal of evolution inserts " to the regulation of the time slot width in the radio frames of 3G (Third Generation) Moblie long evolving system is: for FDD (Frequency Division Duplex, Frequency Division Duplexing (FDD)) system, its time slot adopts the length of 0.5ms, corresponding TTI adopts 0.5ms or 1ms, and the width of its TTI is more than or equal to the time slot width of radio frames; For TDD LTE (long term evolution, Long Term Evolution) optional frame structure, as shown in Figure 1, the length of its radio frames 101 is 10ms, a radio frames comprises the wireless sub-frame 102 and 103 of two 5ms, its time slot 104 and 105 adopts the length of 0.675ms, and corresponding TTI adopts 0.675ms, and the width of its TTI equals the time slot width 0.675ms of radio frames.For TDD LTE compliant frame structure, as shown in Figure 2, the length of its radio frames 106 is 10ms, and its time slot 107 adopts the length of 0.5ms, and corresponding TTI adopts 1ms, and the width of its TTI is greater than the time slot width 0.5ms of radio frames;
3GPP motion R1-070296 " can put case for the emission of the down link multiple-input and multiple-output of TDD mode provide the up emission of all channel state indication: Uplink transmitdiversity scheme to provide full CSI (Channel State Indication; channel status indication) to support downlink MIMO (Multiple Input MultipleOutput; multiple-input and multiple-output) transmission for TDD operation " and provide a kind of terminal use a transmission channel on two antennas with the mode of time-division method to base station transmit signals, the characteristics of this method are: OFDM (the OrthogonalFrequency Division Multiplexing in the time slot, OFDM) symbol is divided into two groups, these two groups of OFDM symbols have the reference signal of oneself respectively, but these two groups of signals belong to the TTI that same length is 0.675ms, one group of OFDM symbol of emission on the antenna of terminal in two antenna, the other one group of OFDM symbol of emission on another antenna.Have only after the time slot of waiting until an optional frame structure, just can carry out demodulation.
The frequency modulation method that 3GPP motion R1-070833 " the up frequency modulation of the optional frame structure of TDD: UplinkFrequency Hopping for TDD with Alternative Frame Structure " provides is: the OFDM symbol in the time slot is divided into two groups, these two groups of OFDM symbols have the reference signal of oneself respectively, but these two groups of signals belong to the TTI that same length is 0.675ms, terminal is in first's time interval of the time slot of optional frame structure, one group of OFDM symbol of emission on one group of OFDM subcarrier, in the second portion time interval of the time slot of optional frame structure, another group of emission OFDM symbol on another group OFDM subcarrier.Have only after the time slot of waiting until an optional frame structure, just can carry out demodulation.
Existing 3G system or other wireless communication systems are that unit arranges business and control signal with the wireless sub-frame, limited the yardstick of the professional asymmetry of up-downgoing that air interface can support, and wireless TTI is the time slot that is greater than or equal to radio frames, though 3GPP motion R1-070296, what R1-070833 provided can realize the flexible transmission of information symbol at TTI under more than or equal to the situation of the time slot width of radio frames less than the transmission method of a time slot, but, the propagation delay time of system, automatically retransmit time delay, the scheduling time delay, and the least resource granularity that each user is distributed does not improve.In addition, for the portable terminal of translational speed greater than 120 kilometers since the correlated time of channel less than 0.5ms, therefore, be the pace of change that least unit chnnel coding of carrying out and scheduling can't adaptive channels with 0.5ms.
Summary of the invention
The technical problem to be solved in the present invention provides a kind of dispatching method that has enlarged the upstream service of TDD communication system of the professional asymmetric range scale of up-downgoing that the TDD air interface can support.
The technical solution adopted for the present invention to solve the technical problems is:
A kind of dispatching method of upstream service of TDD communication system may further comprise the steps:
1.1 the uplink interval of usefulness is not selected in the base station in the ascending time slot of two wireless sub-frames of described tdd communication systems one radio frames, described uplink interval is distributed to terminal as the uplink service time, and will comprise the dispatch command of described uplink service time and send to described terminal;
1.2 described terminal sends service signal according to described dispatch command in the described business hours;
1.3 described base station sends feedback signal to described terminal after receiving described service signal, if also have the not uplink interval of usefulness in the described ascending time slot, then described feedback signal comprises new dispatch command, and gets back to step 1.2, otherwise finishes scheduling;
The method of salary distribution of the uplink and downlink timeslot of described two wireless sub-frames is one of following three kinds of modes:
(1), whole time slots of the last subframe of described two wireless sub-frames are ascending time slot, whole time slots of back one subframe are descending time slot; Perhaps, whole time slots of last subframe are descending time slot, and whole time slots of back one subframe are ascending time slot;
(2), the part time slot of the last subframe of described two wireless sub-frames is ascending time slot, whole time slots of all the other time slots of described last subframe and back one subframe are descending time slot; Perhaps, the part time slot of last subframe is a descending time slot, and whole time slots of all the other time slots of described last subframe and back one subframe are ascending time slot;
(3), whole time slots of the last subframe of described two wireless sub-frames and the part time slot of back one subframe be ascending time slot, all the other time slots of described back one subframe are descending time slot; Perhaps, the part time slot of whole time slots of last subframe and back one subframe is a descending time slot, and all the other time slots of described back one subframe are ascending time slot.
In the such scheme, described dispatch command and feedback signal send to described terminal by described base station by band external feedback passage.
In the such scheme, described band external feedback passage is to realize by introducing the radio frames of working on the unidirectional frequency spectrum of downlink business.
In the such scheme, described uplink interval is the one or more ascending time slot of described wireless sub-frame.
In the such scheme, described uplink interval is the one or more uplink time interval of described wireless sub-frame.
In the such scheme, half that a described uplink time interval is a described ascending time slot.
In the such scheme uplink time interval of a described ascending time slot as the uplink service time, another uplink time interval as the band external feedback time.
Beneficial effect of the present invention mainly shows: technical scheme provided by the invention is passed through less than the TTI of the time slot width of radio frames and corresponding dispatching method, under the prerequisite of taking into account the gain that interweaves of air interface, link feedback overhead, comprehensive use two wireless sub-frames to arrange business, enlarged the asymmetry range scale of the up-downgoing business that the TDD air interface can support; A time slot of a radio frames is divided into the method for the TTI of several inferior slot lengths, makes air interface when business is provided, have better multiple dimensioned characteristic; The feedback delay of system has then been shortened in the introducing of downstream feedback passage.
Description of drawings
Fig. 1 is the optional frame structure schematic diagram of TDD LTE;
Fig. 2 is a TDD LTE compliant frame structural representation;
Fig. 3 is a flow chart of the present invention;
Fig. 4 is that the time slot of the employed wireless frame structure of one embodiment of the invention is arranged schematic diagram;
Fig. 5 is the arrangement schematic diagram of the employed TTI of one embodiment of the invention.
Embodiment
The invention will be further described below in conjunction with accompanying drawing.
As shown in Figure 4, the present invention is the cycle with 10ms, time slot in the wireless sub-frame 102 and 103 of two 5ms that radio frames 101 is comprised comprehensively uses, its method of comprehensively using mainly contains following several: 1, whole time slots of wireless sub-frame 102 are ascending time slot, whole time slots of wireless sub-frame 103 are that whole time slots of descending time slot or wireless sub-frame 102 are descending time slot, and whole time slots of wireless sub-frame 103 are ascending time slot; 2, the part time slot of wireless sub-frame 102 is an ascending time slot, all the other time slots of wireless sub-frame 102 and whole time slots of wireless sub-frame 103 are that the part time slot of descending time slot or wireless sub-frame 102 is a descending time slot, and all the other time slots of wireless sub-frame 102 and whole time slots of wireless sub-frame 103 are ascending time slot; 3, the part time slot of whole time slots of wireless sub-frame 102 and wireless sub-frame 103 is an ascending time slot, all the other time slots of wireless sub-frame 103 are that the whole time slots of descending time slot or wireless sub-frame 102 and the part time slot of wireless sub-frame 103 are descending time slot, and all the other time slots of wireless sub-frame 103 are ascending time slot.Figure 4 shows that the previous case of situation 1.
As shown in Figure 3, a kind of dispatching method of upstream service of TDD communication system, its basic procedure may further comprise the steps:
Step 1: the uplink interval of usefulness is not selected in the base station in the ascending time slot of two wireless sub-frames of tdd communication systems one radio frames, described uplink interval is distributed to terminal as the uplink service time, and will comprise the dispatch command of described uplink service time and send to described terminal;
Step 2: described terminal sends service signal according to described dispatch command in the described business hours;
Step 3: described base station sends feedback signal to described terminal after receiving described service signal, if also have the not uplink interval of usefulness in the described ascending time slot, then described feedback signal comprises new dispatch command, and gets back to step 2, otherwise finishes scheduling.
With respect to the 5ms subframe lengths being cycle arrangement business, with 10ms is to carry out in the cycle after the business time-slot arrangement, the feedback of channel information cycle can extend, ways of addressing this issue is to introduce band external feedback channel transfer dispatch command and feedback information, and it is to introduce the radio frames of working on the unidirectional frequency spectrum of downlink business to realize.
Uplink interval in the dispatching method is one or more ascending time slot.In order to improve the flexibility of service dispatching, introduce the TTI of inferior slot length, promptly this uplink interval also can be one or more TTI.TTI obtains in the following manner: the time slot of radio frames is divided into N subinterval, and the N value is more than or equal to 2 integer, and the typical value of N is 2.In a time slot, finish the transmission of N TTI.As shown in Figure 4, inferior slot length TTI is that the slot length with the optional frame structure of TDDLTE is that example provides, and similarly, also can use the TTI of inferior slot length in TDD LTE compliant frame structure.Time slot 104 adopts the length of 0.675ms, introduces length and be after the TTI of (0.675ms ÷ 2)=0.3375ms, can arrange to belong to the transfer of data of two TTI that different user or user organize in a time slot.Wireless timeslot is divided into the method for N subinterval use and combining of band external feedback passage, both can have reduced propagation delay time, improve the flexibility of dispatching, can effectively shorten feedback delay again, guarantee adaptive capacity quick time-varying channel.
Specify the present invention with as shown in Figure 5 embodiment below.
As shown in Figure 5, two double-direction radio frame subframes 102 and 103 time slot are comprehensively used, and the cycle of comprehensively using time slot is 10ms.In order to realize quick feedback, introduce a radio frames 401 of on descending unidirectional frequency spectrum, working.In the present embodiment, the up-downgoing arrangement method of two double-direction radio frame subframes 102 and 103 time slot is: all time slots of wireless sub-frame 102, and TS1~TS6 is used for up, all time slots of wireless sub-frame 103, TS1~TS6 is used for descending.
The length of TTI among the figure is (0.675 ÷ 2)=0.3375ms, comprises 2 TTI time interval A and B in radio frames 102 and each time slot of 103, and the time span of A and B is 0.3375ms.Six time slots of wireless sub-frame 102, TS1~TS6 has comprised the TTI interval that 12 time spans equal 0.3375ms, that is: six interval and six B intervals of A, the base station is that unit carries out service dispatching with these 12 TTI intervals.
Corresponding with 6 A intervals and 6 B intervals that wireless sub-frame 102 comprises, radio frames 401 comprises time interval a1, a2, a3, a4, a5, a6 and b1, b2, b3, b4, b5, b6.Wherein, if business hours first time of terminal is interval for being TS1_A, then a1 is used for the feedback information of the service signal that the base station sends in terminal sends based on the TS1_A time interval, and this feedback information is used for the emission of uplink service next time of control terminal.The interval of business hours next time of terminal can be any one interval in interval TS2_A/B~TS6_A/B.If be TS2_A between service area, then time interval a2 is used for the feedback information of the service signal that the base station sends in based on the TS2_A time interval to the terminal transmission; If be TS2_B between service area, then time interval b1 is used for the feedback information of the service signal that the base station sends in based on the TS2_B time interval to the terminal transmission.This feedback information is used for the emission of uplink service next time of control terminal, and interval launch time next time of terminal can be any one interval in interval TS3_A/B~TS6_A/B.After this transmission of the feedback information of terminal traffic information emission and base station is by analogizing with upper type.
Radio frames 102 and the 103 two-way frequency spectrums that use are in 2010~2025MHz scope.Descending unidirectional frequency spectrum is in 2010~2025MHz band limits, perhaps is in certain band limits that is allocated to the use of FDD system down link.Descending unidirectional frequency spectrum is the private downlink carrier frequency spectrum shared of TDD system and digital broadcasting or MBMS (Multimedia Broadcast Multicast Service, multimedia broadcast-multicast service) use.
Concrete scheduling process is as follows:
1, the base station sends schedule information by the radio frames 401 of working on the descending unidirectional frequency spectrum to terminal, point out the position of the operable time interval of terminal in the TTI time interval that 12 length are 0.3375ms, such as, the base station is sent to terminal constantly at S and is allowed this terminal use the indication of the time interval A in the TS1, further, the code modulation mode of interval A service time is sent in the base station to terminal;
2, terminal receives after the schedule information and sends business information on the time interval A in TS1;
3, after the data of sending out on the receiving terminal of base station, send feedback signal to terminal in the time interval a1 on the radio frames 401 of working on descending unidirectional frequency spectrum, these feedback signals comprise confirmation of receipt signal, channel quality index signal and new schedule information; Terminal receives the feedback signal that send the base station, carries out the transmission of uplink service signal in next subinterval once more.The base station receives repeats this step after the data that terminal sends and operates in radio frames 102 available up subinterval and be used and finish.