Reduce the method and the base station of HARQ retransmission time interval in the multicarrier system
Technical field
The present invention relates to communication technical field, method and the base station of HARQ in particularly a kind of reduction multicarrier system (Hybrid Automatic Repeat Request mixes automatically retransmitting) RTT (Round-trip Time, retransmission time interval).
Background technology
In the long-term evolution multi-carrier GSM; LTE-Advanced (long-term evolution multi-carrier) system for example; Need higher peak rate be provided through bigger transmission bandwidth, satisfy user's demand, but the expansion of transmission bandwidth be limited by the frequency resource that operator has.For long-term evolution multi-carrier system, for supporting the system bandwidth wideer, such as 100MHz than LTE system; A kind of possibly be the frequency spectrum that directly distributes the 100M bandwidth, but because the frequency resource that operator has is limited, therefore in order to satisfy the bandwidth demand of LTE-A system; Another kind of mode is with distributing to some spectrum aggregatings of existing systems; Gather into big bandwidth and supply with the long-term evolution multi-carrier system use, as shown in Figure 1, be prior art spectrum aggregating system schematic.
Understand in order the present invention to be had clearly, below will be to the uplink-downlink configuration of LTE (Long Term Evolution, Long Term Evolution) system, technology such as maximum process number of HARQ and HARQ re-transmission are carried out brief account.
The LTE system supports FDD (Frequency Division Duplexing; FDD) and two kinds of duplex modes of TDD (Time Division Duplexing, time division duplex), two kinds of dual-modes use different frame structures; Wherein, second type of frame structure (FS2) only is applicable to LTE TDD system.Each radio frames is made up of the long subframe (subframe) of 10 1ms, and each subframe is numbered from 0~9 in order.When being configured to conventional CP (Cyclic Prefix, Cyclic Prefix), each subframe is made up of 14 OFDM (Orthogonal Frequency Division Multiplexing, OFDM) symbol, and each symbol lengths is 2192T
sWhen being configured to expand CP, each subframe is made up of 12 OFDM symbols, and each symbol lengths is 2560T
s, T wherein
s=1/ (15000 * 2048) second.Support two kinds of uplink and downlink switching cycles (being 5ms and 10ms) and 7 kinds of different uplink and downlink proportional arrangement in the system, as shown in table 1 is the uplink/downlink frames configuring condition.
Table 1
Wherein, " D " representes that this subframe is used for downlink transfer in the table, and " U " representes that this subframe is used for uplink; " S " representes special subframe, comprising: " DwPTS ", " GP "; " UpPTS " three zones, wherein DwPTS is used to transmit descending master sync signal and generic downlink business datum, and GP is the protection interval; UpPTS transmission uplink random inserts signal and uplink detection signal; There is the various configurations situation in special subframe, and is as shown in table 2, the OFDM symbolic number that is comprised in the DwPTS zone during for various configuration.
Table 2
The special subframe configuration |
Conventional CP | Expansion CP | |
0 |
3 |
3 |
1 |
9 |
8 |
2 |
10 |
9 |
3 |
11 |
10 |
4 |
12 |
3 |
5 |
3 |
8 |
6 |
9 |
9 |
7 |
10 |
- |
8 |
11 |
- |
If the OFDM symbolic number that DwPTS takies greater than 3, then can be regarded as the generic downlink subframe with this special subframe, transmit any downstream data traffic.If during 3 OFDM symbols that DwPTS only takies, then only exist in the special subframe outside descending master sync signal, accidental access signal and the uplink detection signal, promptly there is not downlink data transmission in the special subframe this moment.According to the difference configuration of DwPTS, the ratio of up-downgoing transmission subframe is as shown in table 3 in the system, when table 3 is the configuration of DwPTS difference, and the maximum process number of proportion of ascending subframe and descending subframe in the system (descending: up) and HARQ.
Table 3
In order to guarantee and the compatibility of LTE system, will continue to use the prior LTE system uplink-downlink configuration on each polymerization carrier wave of upgrade-system.Identical row configuration can be used on each carrier wave, also different uplink-downlink configuration can be used respectively.
In the LTE system, when carrying out the HARQ re-transmission, make a start when sending data, can the information behind the coding be existed in the register.Also can there be the data message after the demodulation in the band register in receiving terminal, and deciphers according to this information.If decipher successfully, then become function signal (ACK) to the feedback decoding of making a start, making a start discharges the information that is kept in the register, and next is organized processing such as data are encoded, storage.If decoding failure, and during the maximum transmission times of no show default, will be to the feedback repeat requests (NACK) of making a start.Make a start receive repeat requests after; Can from register, read out and send once more after partial information is modulated; The information that receiving terminal will receive once more merges with the information that is stored in the register, replaces the information in the former register with the information after merging, and deciphers according to pooling information.
Said process is called a HARQ process, but because there is certain processing handover delay in hardware device, so equipment the time need reserve certain processing time receiving and dispatching conversion, stipulates in the LTE system that this processing delay is minimum to be 4ms (i.e. 4 sub-frame).Therefore the terminal is after receiving packet on the n sub-frame, at the soonest can only be on the n+4 sub-frame feeding back ACK/NAKC information; Same, when the ACK/NAKC feedback is being received in the base station on the n sub-frame after, can only on the n+4 sub-frame, retransmit at the soonest.For the TDD system, owing to can't guarantee subframe n and n+4 symmetry always, and subframe n and n+4 possibly be the upstream or downstream subframes, so for different uplink-downlink configuration, the RTT of system is different.The data packet number that can send continuously before retransmitting of making a start becomes the maximum process number of HARQ.Before deciphering successfully, make a start and receiving terminal stores the corresponding packet of all processes, promptly the process number is big more in the system, and is just high more to the requirement of terminal memory capacity.Different uplink-downlink configuration in the TDD system have been provided with reference to last hurdle of table 3, for the maximum HARQ process of same user number.As shown in Figure 2, be HARQ process sketch map in the prior art, be that example is described with uplink-downlink configuration 2 among this figure, can know that according to table 3 its maximum HARQ process number is 10.
The shortcoming of prior art is, in long-term evolution multi-carrier system, when using multi-carrier polymerizing; Data on each descending carrier will independently be carried out coding and decoding, and maximum HARQ process number in the system will be doubled and redoubled along with the quantity of polymerization carrier wave at this moment; And the process number is many more in the system; RTT is big more, therefore just needs the capacity of terminal memory big more, and then has increased the manufacturing cost of terminal equipment.
Summary of the invention
The object of the invention is intended to solve at least one of above-mentioned technological deficiency, particularly solves in the prior art quantity growth along with the polymerization carrier wave, and the technological deficiency that increases of system process number and RTT.
For achieving the above object; One aspect of the present invention proposes a kind of the reduction and mixes the method that retransmits the HARQ retransmission time interval automatically in the multicarrier system; May further comprise the steps: polymerization is carried out to a plurality of carrier waves in the base station, wherein has at least the configuration of configuration and other carrier waves of a carrier wave inequality with the distribution of ascending resource on time domain in the increase system; Data are sent in said base station on the carrier wave after the polymerization.
As one embodiment of the present of invention; The configuration of the said configuration that has a carrier wave at least and other carrier waves is inequality to be comprised in the distribution on the time domain with ascending resource in the increase system: said each carrier wave is that asynchronous configuration is so that ascending resource maximum distribution on time domain; The wherein said asynchronous subframe numbering that is configured to is asynchronous, and there is side-play amount in the subframe numbering on each carrier wave.
As one embodiment of the present of invention, said side-play amount obtains through following steps: after the user is linked into a carrier wave, know the said side-play amount on other each carrier waves through reading in the system information that broadcasting is sent on the said carrier wave; Perhaps, on each carrier wave, carry out down-going synchronous respectively by said user and obtain said side-play amount voluntarily.
As one embodiment of the present of invention, the configuration of the said configuration that has a carrier wave at least and other carrier waves is inequality to be comprised with the distribution of ascending resource on time domain in the increase system: the ratio of the ascending-descending subframes of at least one said carrier wave greater than the ratio of the average ascending-descending subframes of system with the distribution of ascending resource on time domain in the increase system.
As one embodiment of the present of invention, system obtains the ratio of the average ascending-descending subframes of said system according to the professional ratio of sub-district actual transmissions up-downgoing.Wherein, the employed uplink-downlink configuration of said each carrier wave satisfies existing uplink-downlink configuration 0~6.
As one embodiment of the present of invention, the employed uplink-downlink configuration of said each carrier wave is configured by high level, and notifies said user through broadcast signaling.
As one embodiment of the present of invention; Also comprise: for the feedback information of descending sub frame n, the user uses first ascending resource after the n+T subframe to carry out uplink, perhaps; If said n+T subframe is an ascending resource; Then use said n+T subframe to carry out uplink, wherein, T is the processing delay that system needs.
The present invention also proposes a kind of base station, comprises that polymerization module, polymerization are provided with module and sending module, and said polymerization module is used for a plurality of carrier waves are carried out polymerization; Said polymerization is provided with module, is used for said each carrier wave is provided with, and wherein has at least the configuration of configuration and other carrier waves of a carrier wave inequality with the distribution of ascending resource on time domain in the increase system; Said sending module is used on the carrier wave after the polymerization of said polymerization module, sending data.
As one embodiment of the present of invention, said each carrier wave is asynchronous configuration so that ascending resource maximum distribution on time domain, and the wherein said asynchronous subframe numbering that is configured to is asynchronous, and there is side-play amount in the subframe numbering on each carrier wave.
As one embodiment of the present of invention; After being linked into a carrier wave; The user is known the said side-play amount on other each carrier waves through reading in the system information that broadcasting is sent on the said carrier wave, perhaps, on each carrier wave, carries out down-going synchronous respectively by said user and obtains said side-play amount voluntarily.
As one embodiment of the present of invention, the ratio that said polymerization is provided with the ascending-descending subframes of at least one said carrier wave of module is set to ratio greater than the average ascending-descending subframes of system with the distribution of ascending resource on time domain in the increase system.
As one embodiment of the present of invention, system obtains the ratio of the average ascending-descending subframes of said system according to the professional ratio of sub-district actual transmissions up-downgoing.Wherein, the employed uplink-downlink configuration of said each carrier wave satisfies existing uplink-downlink configuration 0~6.
As one embodiment of the present of invention, the employed uplink-downlink configuration of said each carrier wave is configured by high level, and notifies said user through broadcast signaling.
The present invention is through existing the sub-frame number of ascending resource in the raising system, thereby satisfies under the requirement of the total ascending-descending subframes ratio of system guaranteeing, reduced maximum process number of HARQ and RTT in the system.The present invention has made full use of the system multi-carrier characteristic, has reduced HARQ back off time in the system, thereby has improved the efficiency of transmission of system.
Aspect that the present invention adds and advantage part in the following description provide, and part will become obviously from the following description, or recognize through practice of the present invention.
Description of drawings
Above-mentioned and/or additional aspect of the present invention and advantage are from obviously with easily understanding becoming the description of embodiment below in conjunction with accompanying drawing, wherein:
Fig. 1 is a prior art spectrum aggregating system schematic;
Fig. 2 is a HARQ process sketch map in the prior art;
Fig. 3 reduces the method flow diagram of HARQ retransmission time interval in the multicarrier system for the embodiment of the invention;
Fig. 4 is HARQ sketch map during multi-carrier polymerizing in the prior art;
Fig. 5 is a kind of carrier wave set-up mode of embodiment of the invention sketch map;
Fig. 6 is the another kind of carrier wave set-up mode of an embodiment of the invention sketch map;
Fig. 7 is the structure chart of embodiment of the invention base station.
Embodiment
Describe embodiments of the invention below in detail, the example of said embodiment is shown in the drawings, and wherein identical from start to finish or similar label is represented identical or similar elements or the element with identical or similar functions.Be exemplary through the embodiment that is described with reference to the drawings below, only be used to explain the present invention, and can not be interpreted as limitation of the present invention.
The present invention mainly is, through there being the sub-frame number of ascending resource in the raising system, thereby guarantees under the requirement of satisfying the total ascending-descending subframes ratio of system maximum process number of HARQ and RTT in the reduction system.The present invention has made full use of the system multi-carrier characteristic, has reduced HARQ back off time in the system, thereby has improved the efficiency of transmission of system.
As shown in Figure 3; Reduce the method flow diagram of HARQ retransmission time interval in the multicarrier system for the embodiment of the invention; This embodiment is mainly through existing the sub-frame number of ascending resource in the several method raising system; Thereby guarantee under the requirement of satisfying the total ascending-descending subframes ratio of system maximum process number of HARQ and RTT in the reduction system.This embodiment may further comprise the steps:
Step S301, polymerization is carried out to a plurality of carrier waves in the base station, wherein has at least the configuration of configuration and other carrier waves of a carrier wave inequality with the distribution of ascending resource on time domain in the increase system.Each carrier wave adopts synchronous configuration during polymerization in the prior art, and each carrier wave adopts identical uplink-downlink configuration.As shown in Figure 4, be HARQ sketch map during multi-carrier polymerizing in the prior art, multicarrier system is in the drawings formed by three carrier aggregation, and each carrier wave adopts identical uplink-downlink configuration, for example adopts uplink-downlink configuration 1, and adopts synchronous configuration.Maximum HARQ process number according to its each carrier wave of table 3 is 7, and the maximum HARQ process number after the polymerization is 21 (each carrier wave 3 times), and the RTT of each process is as shown in table 4 below in the system.We can find out that the average RTT of this system is 11.571 from table 4, and this capacity requirement to memory is very high.If adopt the carrier wave of greater number to carry out polymerization in addition, the average RTT of system will be higher.
Table 4
Process |
RTT (subframe) |
1~3,7~12,16~21 |
11 |
4~6,13~15 |
13 |
Average RTT |
11.571 |
As can be seen from Figure 4, the ascending resource in each carrier wave overlaps on time domain, and therefore not only maximum HARQ process number is big for example shown in Figure 4, and RTT is also very high.In order there to be the sub-frame number of ascending resource in the raising system, the present invention need make amendment to the configuration of each carrier wave, thereby satisfies under the requirement of the total ascending-descending subframes ratio of system in assurance, has the sub-frame number of ascending resource in the raising system.As embodiments of the invention; The present invention proposes the method that has the sub-frame number of ascending resource in the multiple raising system; Below will be described with the mode of specific embodiment; But need to prove that following examples only are illustrative examples; Purpose is to make the present invention clearer, but is not that the present invention only can realize through following examples, and those skilled in the art can above-mentioned thought according to the present invention expect existing in other raising systems the additive method of the sub-frame number of ascending resource; Or thought according to the present invention makes modification or the variation that is equal to following embodiment, these additive methods or the modification that is equal to or change and all should be included in of the present invention comprising within the scope.
In one embodiment of the invention; Can adopt set-up mode as shown in Figure 5; Under the identical prerequisite of the total ascending-descending subframes ratio of assurance system, each carrier wave adopts asynchronous configuration so that ascending resource maximum distribution on time domain, and makes and always have uplink transmission resource in each sub-frame.Asynchronous configuration described herein is meant that the subframe numbering is asynchronous, and promptly there is a side-play amount in the subframe numbering on each carrier wave.This side-play amount can obtain in the following manner: after the user is linked into a carrier wave, know the said side-play amount on other each carrier waves through reading in the system information that broadcasting is sent on the said carrier wave; Perhaps, on each carrier wave, carry out down-going synchronous respectively by said user and obtain said side-play amount voluntarily.This embodiment and Fig. 4 are similar; Each carrier wave all adopts uplink-downlink configuration 1; But each carrier wave adopts asynchronous configuration; And the subframe on each carrier wave is carried out sequence offsets, and make that the ascending resource in each carrier wave does not overlap on time domain, thus the sub-frame number that has ascending resource in the raising system.This embodiment is that example is described with uplink-downlink configuration 1, also can adopt other uplink-downlink configuration in other embodiments, repeats no more at this.As can be seen from Figure 5, system shown in Figure 5 compares with system shown in Figure 4, and the total ascending-descending subframes ratio of system is identical; But each carrier wave adopts asynchronous configuration, and makes and always have uplink transmission resource in each subframe, thereby system shown in Figure 5 can guarantee for the downlink transfer among the subframe n; On subframe n+4, always there is uplink resources available to carry out the ACK/NACK feedback; Therefore reduced feedback and the RTT in the system, maximum process number is 16 in the system of Fig. 5 at this moment, and the RTT of each process is as shown in table 5 below in the system; Can find out from table 5 that with respect to table 4 system shown in Figure 5 can significantly reduce the big and RTT of maximum HARQ process number.
Table 5
Process |
RTT (subframe) |
1~5,7~14,16 |
9 |
6,15 |
8 |
Average RTT |
8.875 |
In another embodiment of the present invention, can adopt set-up mode as shown in Figure 6, promptly each carrier wave adopts different uplink-downlink configuration, and wherein, the ratio of the ascending-descending subframes of at least one said carrier wave is greater than the ratio of the average ascending-descending subframes of system.For example if the ratio of total ascending-descending subframes is N (up/descending) in the system; The ratio that then has ascending-descending subframes in the carrier wave at least is greater than N, thereby has improved the sub-frame number that has ascending resource in the system, and is as shown in Figure 6; Three carrier waves adopt uplink-downlink configuration 0, uplink-downlink configuration 1 and uplink-downlink configuration 2 respectively; The ratio of ascending-descending subframes that wherein has a carrier wave at least is greater than the ratio of the average ascending-descending subframes of system,, for example uplink-downlink configuration 0.System shown in Figure 6 is compared with system shown in Figure 4, and the total ascending-descending subframes ratio of system is identical, but the up configuration of each carrier wave is different; Make and exist the uplink transmission resource sub-frame number to increase in the system; Reduced feedback and the RTT in the system, maximum process number is 18 in the system at this moment, and the RTT of each process is as shown in table 6 below in the system; Can find out from table 6 equally that with respect to table 4 system shown in Figure 6 can significantly reduce the big and RTT of maximum HARQ process number.System just can obtain the ratio of the average ascending-descending subframes of said system according to the professional ratio of sub-district actual transmissions up-downgoing like this, thereby carries out uplink-downlink configuration flexibly, further improves efficiency of transmission.The employed uplink-downlink configuration of each carrier wave satisfies existing uplink-downlink configuration 0~6 in the above-described embodiments.Wherein, the employed uplink-downlink configuration of each carrier wave is configured by high level, and notifies said user through broadcast signaling.
Table 6
Process |
RTT (subframe) |
1~18 |
10 |
Average RTT |
10 |
Step S302, data are sent in the base station on the carrier wave after the polymerization.For the user, for the feedback information of descending sub frame n, the user uses first ascending resource after the n+T subframe to carry out uplink; Perhaps; If this n+T subframe is an ascending resource, then use the n+T subframe to carry out uplink, wherein; T is the processing delay (for example for the LTE system, T is 4 sub-frame) that system needs.As another embodiment of the present invention, as shown in Figure 7, be the structure chart of embodiment of the invention base station, this base station 100 comprises that polymerization module 110, polymerization are provided with module 120 and sending module 130.Polymerization module 110 is used for a plurality of carrier waves are carried out polymerization.Polymerization is provided with module 120 and is used for each carrier wave is provided with, and wherein has at least the configuration of configuration and other carrier waves of a carrier wave inequality with the distribution of ascending resource on time domain in the increase system.Sending module 130 is used on the carrier wave after the polymerization of polymerization module, sending data.
As one embodiment of the present of invention, polymerization is provided with module 120 each carrier waves and is set to asynchronous configuration so that ascending resource maximum distribution on time domain.Wherein, can on each time-domain position, have an ascending resource at least.
As one embodiment of the present of invention, the ratio that polymerization is provided with the ascending-descending subframes of module 120 at least one said carrier wave is set to ratio greater than the average ascending-descending subframes of system with the distribution of ascending resource on time domain in the increase system.Wherein, system obtains the ratio of the average ascending-descending subframes of said system according to the professional ratio of sub-district actual transmissions up-downgoing, thereby system can carry out uplink-downlink configuration flexibly, further improves efficiency of transmission.
The present invention is through existing the sub-frame number of ascending resource in the raising system, thereby satisfies under the requirement of the total ascending-descending subframes ratio of system guaranteeing, reduced maximum process number of HARQ and RTT in the system.The present invention has made full use of the system multi-carrier characteristic, has reduced HARQ back off time in the system, thereby has improved the efficiency of transmission of system.
Although illustrated and described embodiments of the invention; For those of ordinary skill in the art; Be appreciated that under the situation that does not break away from principle of the present invention and spirit and can carry out multiple variation, modification, replacement and modification that scope of the present invention is accompanying claims and be equal to and limit to these embodiment.