CN104065449A - Correcting signal sending method and base station - Google Patents

Abstract

The invention discloses a correcting signal sending method and a base station. The correcting signal sending method includes that in a time division duplex system, when a first remote radio frequency unit of a first base station and a second remote radio frequency unit of a second base station need joint correction, the first base station selects a non-pilot time slot of down-link pilot time slots DwPTS of a radio frame to serve as a joint correcting signal sending time slot, wherein the length of the non-pilot time slot is larger than or equal to the length of two OFDM marks; the first base station sends the joint correcting signal to the second base station in the selected non-pilot time slot. Because the length of the non-pilot time slot in the DwPTS is larger than or equal to the length of two OFDM marks, the non-pilot time slot is enough to meet the joint correcting signal sending quality requirement.

Description

The sending method of correction signal and base station

Technical field

The present invention relates to the communications field, relate in particular to sending method and the base station of correction signal.

Background technology

At time division duplex (Time Division Duplexing, TDD) in system, detection reference signal (the Sounding Reference Signal that base station sends by sense terminals (UE), SRS), up channel is estimated, and utilize the reciprocity of TDD system up-downgoing, using the up channel estimating as down channel, carry out wave beam forming.Although TDD system in theory, up-downgoing is reciprocity, but in real system, up-downgoing channel has been introduced respectively different radio-frequency channel, base station, the response of these radio-frequency channels is different, and this just need to compensate these passages by the means of channel correcting.The channel correcting of single subdistrict has maturation method at present.By theory analysis, find, only need the ratio of the up/down row radio-frequency channel that each antenna is corresponding all to equal same value, just can meet the requirement of wave beam forming.

Coordinate multipoint (Coordinative Multiple Point, CoMP) is a key characteristic of Long Term Evolution plan (Long TermEvolution, LTE), utilizes CoMP technology can effectively resist the interference problem of LTE cell edge.Combine transmission (Joint Transmission, JT) technology a kind of as CoMP technology, can significantly improve cell edge and on average handle up.For in TDD system, realize the gain that JT technology is brought, need to carry out channel correcting equally.Yu Dan community wave beam forming technology is different, and the ratio of the up-downgoing radio-frequency channel that each antenna of a plurality of communities of JT Technology Need is corresponding is identical.Even if channel correcting has been carried out respectively in each community, if do not carry out the correction of minizone, JT technology still can not arrive the performance of expectation.Therefore, for JT, need to carry out the correction of combining of minizone.With reference to figure 1, if carry out COMP JT transmission between the community 1 of the community 2 of base station 1 and base station 2 (the main lobe transmit direction of arrow representative antennas wherein), for certain user's service, in order to reach the desired performance of JT, need to combine correction between the long-distance radio frequency unit (Remote Radio Unit, RRU) of the community 2 of base station 1 and the long-distance radio frequency unit of the community 1 of base station 2.

It is that example describes that JT is carried out in Yi Liangge community, and the long-distance radio frequency unit of note community 0 correspondence is RRU0, and corresponding base station is base station 0, and the long-distance radio frequency unit of community 1 correspondence is RRU1, and corresponding base station is base station 1.

Its flow process is roughly as follows:

Fill order community, the base station correcting process that the first step: RRU0 and RRU1 are corresponding;

It is prior art that single RRU carries out inside self-tuning method, and the present embodiment repeats no more.After RRU0 and RRU1 self-correcting complete, obtain separately the self-correcting coefficient of (comprise business receipts passage and business and send out passage) of radio-frequency channel in its each business, self-correcting coefficient comprises that again business is sent out passage self-correcting coefficient (referred to as from correction coefficient) and business is received passage self-correcting coefficient (referred to as receiving self-correcting coefficient).Utilize and receive self-correcting coefficient and respectively uplink receiving and downlink compensated from correction coefficient, just can meet the requirement of TDD system to single RRU up-downgoing reciprocity.

Wherein receive self-correcting coefficient can be expressed as:

${\mathrm{\β}}_{k,i}^{\mathrm{UL}}\left(n\right)=\frac{1}{h_k^{\mathrm{ct}}\left(n\right)h_{k,i}^r\left(n\right)},k=\mathrm{0,1}$

Receipts self-correcting coefficient during k=0 is: ${\mathrm{\β}}_{0,i}^{\mathrm{UL}}\left(n\right)=\frac{1}{h_0^{\mathrm{ct}}\left(n\right)h_{0,i}^r\left(n\right)},$

Receipts self-correcting coefficient during k=1 is: ${\mathrm{\β}}_{1,i}^{\mathrm{UL}}\left(n\right)=\frac{1}{h_1^{\mathrm{ct}}\left(n\right)h_{1,i}^r\left(n\right)}$

Wherein, k represents k RRU, and in the present embodiment, k represents RRU0 at 0 o'clock, and k represents RRU1 at 1 o'clock; N represents n subcarrier, n=0, and 1 ..., N-1, N represents subcarrier number; I represents i business receipts passage, passage (correction channel is sent out in the correction that represents k RRU, comprise proofreading and correct and send out passage and proofread and correct and receive passage, can be radio-frequency channel or all or part ofly reuse radio-frequency channel in business in RRU internal independence, can be also the middle radio-frequency channel that is independent of other autonomous devices outside RRU) channel response on n subcarrier; i the business that represents k RRU received the channel response of passage on n subcarrier.

From correction coefficient, can be expressed as: ${\mathrm{\β}}_{k,i}^{\mathrm{DL}}\left(n\right)=\frac{1}{h_k^{\mathrm{cr}}\left(n\right)h_{k,i}^t\left(n\right)},k=\mathrm{0,1}$

During k=0, from correction coefficient, be: ${\mathrm{\β}}_{0,i}^{\mathrm{DL}}\left(n\right)=\frac{1}{h_0^{\mathrm{cr}}\left(n\right)h_{0,i}^t\left(n\right)}$

During k=1, from correction coefficient, be: ${\mathrm{\β}}_{1,i}^{\mathrm{DL}}\left(n\right)=\frac{1}{h_1^{\mathrm{cr}}\left(n\right)h_{1,i}^t\left(n\right)}$

Wherein, k represents k RRU, and in the present embodiment, k represents RRU0 at 0 o'clock, and k represents RRU1 at 1 o'clock; N represents n subcarrier, n=0, and 1 ..., N-1; I represents that i is sent out passage, the channel response of passage on n subcarrier received in the correction that represents k RRU; i the business that represents k RRU sent out the channel response of passage on n subcarrier.

Second step: RRU0 is controlled by combining correction signal to antenna 0 corresponding to RRU1 between antenna 0 transmitting RRU in base station 0, RRU1 is controlled by combining correction signal to antenna 0 corresponding to RRU0 between antenna 0 transmitting RRU in base station 1, base station 0 and base station 1 utilize penalty coefficient between the RRU receiving between correction signal calculating RRU0 and RRU1, and utilize penalty coefficient between the RRU obtaining to upgrade corresponding Dan community, radio-frequency channel penalty coefficient in RRU1 or RRU0 transmitting-receiving.

Note is utilized base station 0 to receive signal to carry out the domain channel response that channel estimating obtains and be designated as h ₀(n), utilizing base station 0 to receive signal carries out the domain channel response that channel estimating obtains and is designated as h ₁(n), pass through h ₀and h (n) ₁(n) can obtain penalty coefficient between RRU the receipts self-correcting coefficient that upgrades RRU1 is: from correction coefficient, remain unchanged; Or what upgrade RRU1 from correction coefficient is: receiving self-correcting coefficient remains unchanged;

The method can be generalized to single community and adopts a plurality of RRU Two bors d's oeuveres to carry out the scene that signal transmits and receives.

At present, be chosen in the transmission (completing aforementioned second step or the 3rd step in GP) of the associating correction signal between the RRU that carries out minizone in the guard time (Guard Period, GP) between the up-downgoing of TDD radio frames.

It should be noted that, before GP, there is descending pilot frequency time slot DwPTS, after have uplink pilot time slot UpPTS, if base station need to receive by employing business receipts passage when carrying out downlink business transmission by business sendaisle, consider echo impact, need in GP, reserve certain sequential affects to avoid producing echo between DwPTS and the business datum of UpPTS, through experiment, find, when GP only comprises an orthogonal frequency division multiplexi (Orthogonal Frequency Division Multiplexing, OFDM) during symbol, be that DwPTS and UpPTS reserve respectively under the prerequisite of certain hour, cannot meet the quality requirement that associating correction signal sends.

Summary of the invention

The embodiment of the present invention provides the method and apparatus of correction signal, can guarantee associating timing, the quality that associating correction signal sends.

First aspect present invention provides a kind of sending method of correction signal, and it can comprise:

In tdd systems, when between the first long-distance radio frequency unit of the first base station and the second long-distance radio frequency unit of the second base station, need associating timing, the non-pilot time slot that in the descending pilot frequency time slot DwPTS of described the first base station selected radio frames, length is greater than or equal to 2 OFDM symbol lengths is as the time slot that sends associating correction signal;

Described the first base station sends to described the second base station at the non-pilot time slot of described selection by described associating correction signal.

In conjunction with first aspect, in the possible implementation of the first, the length of the guard time GP in the special subframe at described descending pilot frequency time slot DwPTS place equals 1 OFDM symbol lengths.

In conjunction with first aspect, in the possible implementation of the second, the length of described descending pilot frequency time slot DwPTS is greater than 3 OFDM symbol lengths.

In conjunction with first aspect in the possible implementation of the second of first aspect any, in the third possible implementation, the length of described associating correction signal is 1 OFDM symbol lengths.

Second aspect present invention provides a kind of base station, and it can comprise:

Select module, be used at tdd systems, when the first long-distance radio frequency unit of this base station and the second long-distance radio frequency unit of another base station need be combined timing, select non-pilot time slot that in the descending pilot frequency time slot DwPTS of radio frames, length is greater than or equal to 2 OFDM symbol lengths as the time slot that sends associating correction signal;

Anneta module, for sending to described another base station at the selected non-pilot time slot of described selection module by described associating correction signal.

In conjunction with second aspect, in the possible implementation of the first, the length of the guard time GP in the special subframe at the selected descending pilot frequency time slot DwPTS of described selection module place equals 1 OFDM symbol lengths.

In conjunction with second aspect, in the possible implementation of the second, the length of the selected described descending pilot frequency time slot DwPTS of described selection module is greater than 3 OFDM symbol lengths.

In conjunction with second aspect in the possible implementation of the second of first aspect any, in the third possible implementation, the length of described associating correction signal is 1 OFDM symbol lengths.

Therefore, in feasible execution modes more of the present invention, in tdd systems, when between the first long-distance radio frequency unit of the first base station and the second long-distance radio frequency unit of the second base station, need associating timing, the non-pilot time slot that in the descending pilot frequency time slot DwPTS of described the first base station selected radio frames, length is greater than or equal to 2 OFDM symbol lengths is as the time slot that sends associating correction signal; Described the first base station sends to described the second base station at the non-pilot time slot of described selection by described associating correction signal.Because the length of the non-pilot time slot in DwPTS is all greater than or equal to 2 OFDM symbols, the enough transmission quality requirement of satisfied associating correction signal so just.

Accompanying drawing explanation

Fig. 1 is the distribution schematic diagram of base station and community in mobile radio communication;

Fig. 2 is that the structure of radio frames of the present invention forms schematic diagram;

Fig. 3 is the schematic flow sheet of an embodiment of the sending method of correction signal of the present invention;

Fig. 4 shows the pilot tone pattern of the special subframe under 1 antenna;

Fig. 5 is the structural representation of an embodiment of base station of the present invention.

Embodiment

For making the object, technical solutions and advantages of the present invention clearer, below in conjunction with accompanying drawing, the present invention is described in further detail.

Fig. 2 is that the structure of radio frames of the present invention forms schematic diagram.As shown in Figure 2; each radio frames comprises 2 fields; wherein subframe 0 to subframe 4 is previous field; subframe 5 to subframe 9 is a rear field; wherein subframe 1 and subframe 6 are special subframe; these two special subframes comprise descending pilot frequency time slot DwPTS, guard time GP, and uplink pilot time slot UpPTS.When carrying out sub-frame configuration, to the configuration of these two special subframes can be as shown in table 1 (unit in table 1 is OFDM symbol, and such as 10 in GP column represents, the length of GP is 10 OFDM, and 1 represents that the length of GP is 1 OFDM):

Table 1 (lower behavior regular circulation verification (CP, cyclic prefix) is example):

As shown in Table 1, in some cases, the length of the GP of configuration is just an OFDM, therefore, is considering that, under the situation of echo impact, the GP of single OFDM length cannot meet the quality requirement that associating correction signal sends.

Therefore, the embodiment of the present invention has proposed a kind of sending method of brand-new correction signal, for making up the GP of single OFDM symbol as the deficiency of associating correction signal transmitting time.Concrete, the schematic flow sheet of an embodiment of the sending method that Fig. 3 is correction signal of the present invention.It can comprise:

Step S110, in tdd systems, when the first long-distance radio frequency unit of the first base station and the second long-distance radio frequency unit of the second base station need be combined timing, the non-pilot time slot that in the descending pilot frequency time slot DwPTS of described the first base station selected radio frames, length is greater than or equal to 2 OFDM symbol lengths is as the time slot that sends associating correction signal;

Step S111, described the first base station (can be base station 1 or base station 2 in Fig. 1) sends to described the second base station at the non-pilot time slot of described selection by described associating correction signal, and (during when the first Wei Tu1Zhong base station 1, base station, the second base station herein can be base station 2; When the first base station is the base station 2 in Fig. 1, the second base station herein can be base station 1).

In some feasible implementations, at step S110, the length of the guard time GP in the special subframe at described the first base station selected descending pilot frequency time slot DwPTS place equals 1 OFDM symbol lengths.Reference table 1 is known, and when the length of GP equals an OFDM symbol, the length of the DwPTS before it is respectively 11 and 12 OFDM symbols.Further, Fig. 4 shows the pilot tone pattern of the special subframe under 1 antenna, in Fig. 4, and l=0,1 ... .6, has occurred twice, wherein, previous l=0,1, ... .6, represents first slot of this special subframe, a rear l=0,1 ... .6, represents second slot of this special subframe, in Fig. 4, each row represents an OFDM symbol duration, and hence one can see that, and a special subframe comprises 14 OFDM durations.And R wherein ₀for pilot tone, can not be corrected signal and take.

Associative list 1, when the length of DwPTS is 11 OFDM symbols, corresponding to Fig. 4 is the l=0 in first slot and the 2nd slot, 1,2,3 are DwPTS, and hence one can see that, when the length of GP equals an OFDM symbol, the l=1 of first slot in DwPTS, 2,3,5,6 is idle, the l=1 of second slot, 2,3 is idle, and the length of the l=1-3 of first slot is 3 OFDM, the length of l=5-6 is 2 OFDM, and the length of the l=1-3 of second slot is 3 OFDM.And when the length of DwPTS is 12 OFDM symbols, corresponding to Fig. 4 is the l=0 in first slot and the 2nd slot, 1,2,3,4 are DwPTS, and hence one can see that, when the length of GP equals an OFDM symbol, the l=1 of first slot in DwPTS, 2,3,5,6 is idle, the l=1 of second slot, 2,3 is idle, and the length of the l=1-3 of first slot is 3 OFDM, the length of l=5-6 is 2 OFDM, and the length of the l=1-3 of second slot is 3 OFDM; Through experiment showed,, is considering under the situation of echo impact, the time slot of two and above OFDM length all can meet the quality requirement of associating correction signal transmission.Therefore; in specific implementation; when the length of GP equals an OFDM symbol; the length of the non-pilot time slot in DwPTS is all greater than or equal to the length of two OFDM; therefore; select the length of guard time GP in radio frames to equal non-pilot time slot in the DwPTS in the subframe of an OFDM symbol as the time slot that sends associating correction signal, can meet the quality requirement of associating correction signal transmission.

In some feasible execution modes, in step S110, the length of selected descending pilot frequency time slot DwPTS is greater than 3 OFDM symbol lengths.Still reference table 1 and Fig. 4, when the length of descending pilot frequency time slot DwPTS is greater than 3 OFDM symbol lengths, in DwPTS, can occur that length is equal to, or greater than the non-pilot tone OFDM symbol of 2 OFDM symbol lengths, therefore, length is greater than the quality requirement of the satisfied associating correction signal transmission of DwPTS total energy of 3 OFDM symbol lengths.

In some feasible execution modes, the length of described associating correction signal can be 1 OFDM symbol lengths, and the length of described associating correction signal is less than or equal to the time slot of associating correction signal, the time span taking for actual transmission correction signal.

Therefore, in feasible execution modes more of the present invention, in tdd systems, when between the first long-distance radio frequency unit of the first base station and the second long-distance radio frequency unit of the second base station, need associating timing, the non-pilot time slot that in the descending pilot frequency time slot DwPTS of described the first base station selected radio frames, length is greater than or equal to 2 OFDM symbol lengths is as the time slot that sends associating correction signal; Described the first base station sends to described the second base station at the non-pilot time slot of described selection by described associating correction signal.Because the length of the non-pilot time slot in DwPTS is all greater than or equal to 2 OFDM symbols, the enough transmission quality requirement of satisfied associating correction signal so just.

In specific implementation, the method for the embodiment of the present invention can be applicable to the second step described in background technology and the 3rd step, for improving the deficiency of combining correction between background technology small area.

Accordingly, the embodiment of the present invention provides the base station equipment that can be used for implementing said method, and as shown in Figure 5, the base station that the embodiment of the present invention provides (can be base station 1 or base station 2 in Fig. 1) can comprise: select module 51 and Anneta module 52, wherein:

Select module 51, be used at tdd systems, when the first long-distance radio frequency unit of this base station and the second long-distance radio frequency unit of another base station need be combined timing, select non-pilot time slot that in the descending pilot frequency time slot DwPTS of radio frames, length is greater than or equal to 2 OFDM symbol lengths as the time slot that sends associating correction signal;

Anneta module 52, for described associating correction signal being sent to described another base station at the selected non-pilot time slot of described selection module 51, (during when Wei Tu1Zhong base station 1, base station above, another base station herein can be base station 2; When base station is above the base station 2 in Fig. 1, another base station herein can be base station 1).

In some feasible execution modes, the length of the guard time GP in the special subframe at the selected descending pilot frequency time slot DwPTS of described selection module 51 place equals 1 OFDM symbol lengths.Reference table 1 is known, and when the length of GP equals an OFDM symbol, the length of the DwPTS before it is respectively 11 and 12 OFDM symbols.Further, Fig. 4 shows the pilot tone pattern of the special subframe under 1 antenna, in Fig. 4, and l=0,1 ... .6, has occurred twice, wherein, previous l=0,1, ... .6, represents first slot of this special subframe, a rear l=0,1 ... .6, represents second slot of this special subframe, in Fig. 4, each row represents an OFDM symbol duration, and hence one can see that, and a special subframe comprises 14 OFDM durations.And R wherein ₀for pilot tone, can not be corrected signal and take.

Associative list 1, when the length of DwPTS is 11 OFDM symbols, corresponding to Fig. 4 is the l=0 in first slot and the 2nd slot, 1,2,3 are DwPTS, and hence one can see that, when the length of GP equals an OFDM symbol, the l=1 of first slot in DwPTS, 2,3,5,6 is idle, the l=1 of second slot, 2,3 is idle, and the length of the l=1-3 of first slot is 3 OFDM, the length of l=5-6 is 2 OFDM, and the length of the l=1-3 of second slot is 3 OFDM.And when the length of DwPTS is 12 OFDM symbols, corresponding to Fig. 4 is the l=0 in first slot and the 2nd slot, 1,2,3,4 are DwPTS, and hence one can see that, when the length of GP equals an OFDM symbol, the l=1 of first slot in DwPTS, 2,3,5,6 is idle, the l=1 of second slot, 2,3 is idle, and the length of the l=1-3 of first slot is 3 OFDM, the length of l=5-6 is 2 OFDM, and the length of the l=1-3 of second slot is 3 OFDM; Through experiment showed,, is considering under the situation of echo impact, the time slot of two and above OFDM length all can meet the quality requirement of associating correction signal transmission.Therefore; in specific implementation; when the length of GP equals an OFDM symbol; the length of the non-pilot time slot in DwPTS is all greater than or equal to the length of two OFDM; therefore; select the length of guard time GP in radio frames to equal non-pilot time slot in the DwPTS in the subframe of an OFDM symbol as the time slot that sends associating correction signal, can meet the quality requirement of associating correction signal transmission.

In some feasible execution modes, the length of the selected described descending pilot frequency time slot DwPTS of described selection module 51 is greater than 3 OFDM symbol lengths.Still reference table 1 and Fig. 4, when the length of descending pilot frequency time slot DwPTS is greater than 3 OFDM symbol lengths, in DwPTS, can occur non-pilot tone that length is equal to, or greater than 2 OFDM symbol lengths therefore, the DwPTS total energy that length is greater than 3 OFDM symbol lengths meets the quality requirement of associating correction signal transmission.

In some feasible execution modes, the length of the associating correction signal that Anneta module 52 sends can be 1 OFDM symbol lengths.When it can avoid 1/4 OFDM symbol lengths of available technology adopting, subcarrier spacing is easily subject to the problem (1/4 OFDM symbol lengths subcarrier spacing is 60kHz, and the subcarrier spacing of 1 OFDM symbol lengths is 15kHz) of multi-path influence.

Cited is only preferred embodiment of the present invention above, certainly can not limit with this interest field of the present invention, and the equivalent variations of therefore doing according to the claims in the present invention, still belongs to the scope that the present invention is contained.

Claims (8)

1. a sending method for correction signal, is characterized in that, comprising:

In tdd systems, when between the first long-distance radio frequency unit of the first base station and the second long-distance radio frequency unit of the second base station, need associating timing, the non-pilot time slot that in the descending pilot frequency time slot DwPTS of described the first base station selected radio frames, length is greater than or equal to 2 OFDM symbol lengths is as the time slot that sends associating correction signal;

Described the first base station sends to described the second base station at the non-pilot time slot of described selection by described associating correction signal.

2. the sending method of correction signal as claimed in claim 1, is characterized in that, the length of the guard time GP in the special subframe at described descending pilot frequency time slot DwPTS place equals 1 OFDM symbol lengths.

3. the sending method of correction signal as claimed in claim 1, is characterized in that, the length of described descending pilot frequency time slot DwPTS is greater than 3 OFDM symbol lengths.

4. the sending method of the correction signal as described in any one in claim 1-3, is characterized in that, the length of described associating correction signal is 1 OFDM symbol lengths.

5. a base station, is characterized in that, comprising:

Select module, be used at tdd systems, when the first long-distance radio frequency unit of this base station and the second long-distance radio frequency unit of another base station need be combined timing, select non-pilot time slot that in the descending pilot frequency time slot DwPTS of radio frames, length is greater than or equal to 2 OFDM symbol lengths as the time slot that sends associating correction signal;

Anneta module, for sending to described another base station at the selected non-pilot time slot of described selection module by described associating correction signal.

6. base station as claimed in claim 5, is characterized in that, the length of the guard time GP in the special subframe at the selected descending pilot frequency time slot DwPTS of described selection module place equals 1 OFDM symbol lengths.

7. base station as claimed in claim 5, is characterized in that, the length of the selected described descending pilot frequency time slot DwPTS of described selection module is greater than 3 OFDM symbol lengths.

8. the base station as described in claim 5-7, is characterized in that, the length of described associating correction signal is 1 OFDM symbol lengths.