CN102045094B - Method for transmitting downlink signals - Google Patents

Abstract

The invention provides a method for transmitting downlink signals. In the method, the signals are transmitted in a plurality of effective remote radio units (RRU) in a diversity transmission mode and the downlink signals of each RRU are subjected to frequency offset precompensation before each RRU transmits the downlink signals of user equipment (UE) to the UE to ensure that the downlink signals transmitted by all effective RRUs have the same Doppler frequency offset before reaching the UE, so that the influence of different Doppler frequency offsets of downlink signals from different RRUs on the detection performance of the downlink receiving signal on the UE side in the high-speed scene is eliminated, and the UE can obtain the receiving diversity gain brought by a plurality of RRUs. Therefore, by using the method, the performance of detecting the downlink signals by the UE in the high-speed scene can be effectively improved.

Description

A kind of sending method of downstream signal

Technical field

The present invention relates to the transmission technology of downstream signal in the mobile communication system, particularly relate to the sending method of downstream signal in the high speed scene.

Background technology

In the high speed scene, will erect many poles (referring to shown in Figure 1) along high-speed railway or highway.Hang two remote radio unit (RRU)s (RRU) on each pole.The type of RRU can be: single channel RRU or multichannel RRU.A sub-district is made up of the RRU on a plurality of poles.The band shape that these RRU form the sub-district covers.

In above-mentioned high speed scene, a subscriber equipment (UE) can only be received by several RRU in the sub-district usually by the upward signal that any one up channel of distributing to it sends, and these RRU are exactly effective RRU of UE.Because the relative position between the high-speed mobile of UE and UE and each effective RRU is different, the Doppler frequency deviation the when upward signal of UE by the up channel transmission arrives each RRU is different.To the received signal of UE, can determine all effective RRU of UE according to each RRU, and can determine that each effective RRU goes up the Doppler frequency deviation of the upward signal of UE by the upward signal of up channel transmission.The method of determining effective RRU of UE sees also existing pertinent literature with the method for determining the Doppler frequency deviation of the upward signal of UE on each effective RRU.

At down direction, because the high-speed mobile of UE and the relative position difference between UE and each RRU, the Doppler frequency deviation the when downstream signal that each RRU any one down channel by UE sends arrives UE is different usually.For UE, be regarded as multipath signal from the downstream signal of different RRUs.When the Doppler frequency deviation in every footpath in the multipath signal was different, because UE is limited to the follow-up control of the frequency deviation of downstream signal, UE was difficult to effectively follow the tracks of the carrier frequency varies of downstream signal.

For solving the tracking problem of high speed scene UE to the carrier frequency of downstream signal, proposed at present to adopt following solution: the power that calculates the UE upward signal that each effective RRU receives, select the strongest RRU of power, only send the downstream signal of any one down channel of this UE at down direction by the strongest RRU of this power.Like this, can avoid the different problem of multi-frequency frequency deviation that causes by the downstream signal that different RRUs sends UE that UE receives, make UE can follow the tracks of the carrier frequency varies of high speed scene downstream signal from the downstream signal of different RRUs.

When only sending the downstream signal of down channel of UE by the strongest RRU of power, the Doppler frequency deviation of the downstream signal of the down channel that UE receives will change regularly: in the overlay area that two RRU open on same pole, when UE more and more near this pole the time, the frequency deviation of the downstream signal that UE receives changes to 0 from f, here, f be on the occasion of; As UE more and more away from this pole the time, the frequency deviation of the downstream signal that UE receives changes from 0 to-f; And when UE went to the area of coverage of another pole from the area of coverage of a pole, the inclined to one side saltus step of two frequencys multiplication can appear in the downstream signal that UE receives.Below in conjunction with Fig. 1, the above-mentioned frequency deviation Changing Pattern of the downstream signal that detailed description UE receives.

Among Fig. 1,8 RRU on 4 poles form a sub-district.When UE entered the coverage of sub-district B and drives towards RRU1/RRU2, the upward signal that RRU1 receives UE was the strongest, and therefore, base station (NodeB) will send the downstream signal of UE by RRU1.Gradually near in the process of RRU1, the frequency deviation of the signal of the RRU1 that UE receives changes to 0 from f at UE.Here, f be on the occasion of.When UE sails out of RRU1/RRU2 gradually, in the close process of RRU3/RRU4, the upward signal that RRU2 receives UE is the strongest.Therefore, NodeB will send the downstream signal of UE by RRU2.At UE gradually in the process away from RRU2, the frequency deviation of the signal of the RRU2 that UE receives changes from 0 to-f.Because the area of coverage of RRU1/RRU2 is left in motion, and when entering the area of coverage of RRU3/RRU4, the upward signal that RRU3 receives UE is the strongest, therefore, NodeB will send the downstream signal of UE by RRU3 as UE.Gradually near in the process of RRU3, the frequency deviation of the signal of the RRU3 that UE receives changes to 0 from f at UE.At the area of coverage of UE from RRU1/RRU2, when just having entered the area of coverage of RRU3/RRU4, the inclined to one side saltus step of two frequencys multiplication can appear in the down receiving signal of UE: the frequency deviation of down receiving signal is the frequency deviation f of the received signal of RRU3 from the frequency deviation-f saltus step of the received signal of RRU2.In the motion process of UE, the variation of the frequency deviation of UE down receiving signal repeats above-mentioned rule afterwards.

The frequency deviation Changing Pattern of the downstream signal that receives in view of above-mentioned UE, also propose in the existing above-mentioned solution: when sending the downstream signal of any one down channel of UE by selecteed RRU, the downstream signal that sends is carried out the precompensation of Doppler frequency deviation, can reach following two purposes by this precompensation:

1) makes the carrier frequency varies of the downstream signal of adjacent two subframes that UE receives be not more than the threshold value that sets in advance, cause UE can't effectively follow the tracks of the variation of downstream signal carrier frequency with the carrier frequency generation saltus step of the downstream signal that prevents adjacent two subframes.

2) carry out the Doppler frequency deviation precompensation by downstream signal to any one down channel, carrier frequency when the upward signal that makes UE pass through any one up channel transmission arrives NODEB is close to the carrier frequency of NODEB, makes UE trend towards 0 by the Doppler frequency deviation of the upward signal of any one up channel transmission.This method can effectively avoid taking place to occur when pole switches as the RRU that sends the UE downstream signal saltus step of the carrier frequency generation twice frequency deviation of the downstream signal that UE receives.

The sending method of downstream signal in the above-mentioned high speed scene had both made things convenient for UE in the tracking of high speed scene to the frequency of the downstream signal of down channel, can improve the demodulation performance of UE to downstream signal again.

But, the sending method of above-mentioned downstream signal only sends the downstream signal of UE by a RRU at down direction, like this, though avoided the frequency deviation different problem in each footpath in the multipath signal, make UE can't obtain many RRU and send the receive diversity that downstream signals institute can bring and gain.In addition, this method is only applicable to single channel RRU.

Summary of the invention

In view of this, main purpose of the present invention is to provide a kind of sending method of downstream signal, and this method is applicable in the high speed scene, can make UE obtain the receive diversity gain, effectively improves UE detection performance to downstream signal in the high speed scene.

In order to achieve the above object, the technical scheme of the present invention's proposition is:

A kind of sending method of downstream signal, this method may further comprise the steps:

A, in current subframe, all effective remote radio unit (RRU)s (RRU) of subscriber equipment (UE) are determined in the base station, and determine that each described effective RRU goes up the Doppler frequency deviation p (i of the upward signal of this UE, n), wherein, i is the numbering of arbitrary described effective RRU, and n is the numbering of current subframe;

The power that each described effective RRU goes up the upward signal of UE is calculated in b, base station, select prominent effective RRU as benchmark RRU, described Doppler frequency deviation p (l according to described benchmark RRU, n), determine the accumulative total compensate of frequency deviation amount u (l of described benchmark RRU, n), wherein, l is the numbering of described benchmark RRU;

C, base station are according to the accumulative total compensate of frequency deviation amount u (l of described benchmark RRU, n) and described Doppler frequency deviation p (i, n), according to u (m, n)=u (l, n)+and p (m, n)-p (l, n), determine the accumulative total compensate of frequency deviation amount u (m of each the effective RRU except that described benchmark RRU, n), wherein, m is the numbering of the arbitrary effective RRU except that described benchmark RRU;

D, at n+d _UlSubframe, base station be at each described effective RRU, according to the accumulative total compensate of frequency deviation amount u of this RRU (i, n), to this effective RRU at n+d _UlThe downstream signal of this UE that subframe sends carries out frequency deviation pre-compensation, utilizes this effective RRU will send to described UE through the downstream signal behind the frequency deviation pre-compensation, wherein, and d _UlBe base station execution in step a, b and needed time of c.

Preferably, the frequency deviation pre-compensation in the described steps d is:

When described effective RRU is described benchmark RRU, and when being single channel RRU, the base station according to $S(l,n+d_{\mathrm{ul}},k)=s(n+d_{\mathrm{ul}},k)\·e^{-j2\mathrm{\π}\·u(l,n)\·(k-1)\·\mathrm{SF}\·T_c},$ Downstream signal s (n+d to described UE _Ul, k) carry out frequency deviation pre-compensation, obtain downstream signal S (l, n+d behind the frequency deviation pre-compensation _Ul, k), wherein, k is the numbering of the arbitrary symbol in the symbol sebolic addressing of described downstream signal, SF represents the spreading factor of the down channel of described UE, T _cThe duration of a chip of expression;

When described effective RRU is described benchmark RRU, and when being multichannel RRU, the base station determine described UE down beam shaping weight vector w (l, n), according to $S(l,n+d_{\mathrm{ul}},k)=w(l,n)s(n+d_{\mathrm{ul}},k)\·e^{-j2\mathrm{\π}\·u(l,n)\·(k-1)\·\mathrm{SF}\·T_c},$ Downstream signal s (n+d to described UE _Ul, k) carry out frequency deviation pre-compensation, obtain downstream signal S (l, n+d behind the frequency deviation pre-compensation _Ul, k), wherein, w (l, n)=[w (l, n, 1), w (l, n, 2) ..., w (l, n, N _{Ant, l})], v=1 ..., N _{Ant, l}, (l, n v) represent the beam shape-endowing weight value of v the passage of this RRU, N to w _{Ant, l}Represent the number of active lanes that this RRU comprises, S (l, n+d _Ul, k)=[S (l, n+d _Ul, k, 1), S (l, n+d _Ul, k, 2) ..., S (l, n+d _Ul, k, N _{Ant, l})], $S(l,n+d_{\mathrm{ul}},k,v)=w(l,n,v)s(n+d_{\mathrm{ul}},k)\·e^{-j2\mathrm{\π}\·u(l,n)\·(k-1)\·\mathrm{SF}\·T_c},$ K is the numbering of the arbitrary symbol in the symbol sebolic addressing of described downstream signal, and SF represents the spreading factor of the down channel of described UE, and Tc represents the duration of a chip;

When described effective RRU is arbitrary described effective RRU except that described benchmark RRU, and when being single channel RRU, the base station according to $S(m,n+d_{\mathrm{ul}},k)=s(n+d_{\mathrm{ul}},k)\·e^{-j2\mathrm{\π}\·u(m,n)\·(k-1)\·\mathrm{SF}\·T_c},$ Downstream signal s (n+d to described UE _Ul, k) carry out frequency deviation pre-compensation, obtain downstream signal S (m, n+d behind the frequency deviation pre-compensation _Ul, k), wherein, k is the numbering of the arbitrary symbol in the symbol sebolic addressing of described downstream signal, SF represents the spreading factor of the down channel of described UE, T _cThe duration of a chip of expression;

When described effective RRU is arbitrary described effective RRU except that described benchmark RRU, and when being multichannel RRU, the base station determine described UE down beam shaping weight vector w (m, n), according to $S(m,n+d_{\mathrm{ul}},k)=w(m,n)s(n+d_{\mathrm{ul}},k)\·e^{-j2\mathrm{\π}\·u(m,n)\·(k-1)\·\mathrm{SF}\·T_c},$ Downstream signal s (n+d to described UE _Ul, k) carry out frequency deviation pre-compensation, obtain downstream signal S (m, n+d behind the frequency deviation pre-compensation _Ul, k), wherein, w (m, n)=[w (m, n, 1), w (m, n, 2) ..., w (m, n, N _{Ant, m})], w (m, n v) represent the beam shape-endowing weight value of v the passage of this RRU, v=1 ..., N _{Ant, m}, N _{Ant, m}Represent the number of active lanes that this RRU comprises, S (m, n+d _Ul, k)=[S (m, n+d _Ul, k, 1), S (m, n+d _Ul, k, 2) ..., S (m, n+d _Ul, k, N _{Ant, m})], $S(m,n+d_{\mathrm{ul}},k,v)=w(m,n,v)s(n+d_{\mathrm{ul}},k)\·e^{-j2\mathrm{\π}\·u(m,n)\·(k-1)\·\mathrm{SF}\·T_c},$ K is the numbering of the arbitrary symbol in the symbol sebolic addressing of described downstream signal, and SF represents the spreading factor of the down channel of described UE, T _cThe duration of a chip of expression.

The present invention proposes the sending method of another kind of downstream signal, this method may further comprise the steps:

A, in current subframe, all effective remote radio unit (RRU)s (RRU) of subscriber equipment (UE) are determined in the base station, and determine that each described effective RRU goes up the Doppler frequency deviation p (i of the upward signal of this UE _n, n), wherein, i _nBe the numbering of arbitrary described effective RRU of determining in the n subframe, n is the numbering of current subframe;

The power that each described effective RRU goes up the upward signal of UE is calculated in b, base station, selects prominent effective RRU as benchmark RRU, according to the described Doppler frequency deviation p (l of described benchmark RRU _n, n) and the frequency deviation pre-compensation amount u (l of the benchmark RRU that determines in the n-1 subframe _N-1, n-1) with Doppler frequency deviation p (l _N-1, n-1), calculate the frequency deviation pre-compensation amount u (l of the described benchmark RRU that determines in the n subframe _n, n), wherein, l _nBe the numbering of the benchmark RRU that determines in the n subframe, l _N-1It is the numbering of the benchmark RRU that determines in the n-1 subframe;

C, according to the frequency deviation pre-compensation amount u (l of described benchmark RRU _n, n) with described Doppler frequency deviation p (i _n, n), according to u (m _n, n)=u (l _n, n)+p (m _n, n)-p (l _n, n), calculate the frequency deviation pre-compensation amount u (m of each the effective RRU except that described benchmark RRU in determined all the effective RRU of n subframe _n, n), wherein, m _nNumbering for the arbitrary effective RRU except that described benchmark RRU;

D, at n+d _UlSubframe is at determined each the effective RRU of n subframe, according to the frequency deviation pre-compensation amount u (i of this RRU _n, n), to this RRU at n+d _UlThe downstream signal that subframe need send to described UE carries out frequency deviation pre-compensation, utilizes this RRU will send to described UE through the downstream signal behind the frequency deviation pre-compensation, wherein, and d _UlBe base station execution in step a, b and needed time of c.

Preferably, calculate the frequency deviation pre-compensation amount u (l of the described benchmark RRU that determines in the n subframe among the described step b _n, n) be:

When n subframe is first sub-frame of uplink after described UE inserts, according to u (l _n, n)=0 calculate described frequency deviation pre-compensation amount u (l _n, n);

When n subframe is described UE when inserting any one sub-frame of uplink except that first sub-frame of uplink of back, if the switching of described UE between n subframe generation pole, then according to u (l _n, n)=u (l _N-1, n-1)+p (l _n, n)-p (l _N-1, n-1) calculate described frequency deviation pre-compensation amount u (l _n, n), otherwise according to u (l _n, n)=u (l _N-1, n-1) calculate described frequency deviation pre-compensation amount u (l _n, n).

Preferably, the described frequency deviation pre-compensation in the steps d is:

When described effective RRU is single channel RRU, the base station according to $S(i_n,n+d_{\mathrm{ul}},k)=s(n+d_{\mathrm{ul}},k)\·e^{-j2\mathrm{\π}\·u(i_n,n)\·(k-1)\·\mathrm{SF}\·T_c},$ Downstream signal s (n+d to described UE _Ul, k) carry out frequency deviation pre-compensation, obtain the downstream signal S (i behind the frequency deviation pre-compensation _n, n+d _Ul, k), wherein, k is the numbering of the arbitrary symbol in the symbol sebolic addressing of described downstream signal, and SF represents the spreading factor of the down channel of described UE, and Tc represents the duration of a chip;

When described effective RRU was multichannel RRU, the down beam shaping weight vector w (i of described UE was determined in the base station _n, n), according to $(i_n,n+d_{\mathrm{ul}},k)=w(i_n,n)s(n+d_{\mathrm{ul}},k)\·e^{-j2\mathrm{\π}\·u(i_n,n)\·(k-1)\·\mathrm{SF}\·T_c}$ Downstream signal s (n+d to described UE _Ul, k) carry out frequency deviation pre-compensation, obtain the downstream signal S (i behind the frequency deviation pre-compensation _n, n+d _Ul, k), wherein, $w(i_n,n)=[w(i_n,n,1),w(i_n,n,2),......,w(i_n,n,N_{\mathrm{ant},i_n})],$ W (m, n v) represent the beam shape-endowing weight value of v the passage of this RRU, $v=1,...,N_{\mathrm{ant},i_n},$

Represent the number of active lanes that this RRU comprises, $S(i_n,n+d_{\mathrm{ul}},k)=[S(i_n,n+d_{\mathrm{ul}},k,1),S(i_n,n+d_{\mathrm{ul},}k,2),......,S(i_n,n+d_{\mathrm{ul}},k,N_{\mathrm{ant},i_n})],$ $S(i_n,n+d_{\mathrm{ul}},k,v)=w(i_n,n,v)s(n+d_{\mathrm{ul}},k)\·e^{-j2\mathrm{\π}\·u(i_n,n)\·(k-1)\·\mathrm{SF}\·T_c},$ K is the numbering of the arbitrary symbol in the symbol sebolic addressing of described downstream signal, and SF represents the spreading factor of the down channel of described UE, and Tc represents the duration of a chip.

In sum, the present invention proposes the sending method of downstream signal in a kind of high speed scene, this method adopts the mode of diversity transmission to carry out the transmission of downstream signal in a plurality of effective RRU, and before each RRU sends to UE with the downstream signal of UE, downstream signal to each RRU carries out preliminary treatment, promptly carry out frequency deviation pre-compensation, so that the downstream signal that issues from all effective RRU has identical Doppler frequency deviation when arriving UE, thereby can overcome in the high speed scene because inequality and UE side down receiving signal is detected Effect on Performance from the multispectral frequency deviation of reining in of the downstream signal of different RRUs, can make simultaneously UE obtain many RRU and send the receive diversity gain that is brought, as seen, the present invention can effectively improve UE detection performance to downstream signal in the high speed scene.

Description of drawings

Fig. 1 is the networking schematic diagram of high-speed railway scene;

Fig. 2 is the flow chart of the embodiment of the invention one;

Fig. 3 is the flow chart of the embodiment of the invention two.

Embodiment

For making the purpose, technical solutions and advantages of the present invention clearer, the present invention is described in further detail below in conjunction with the accompanying drawings and the specific embodiments.

Core concept of the present invention is: at the high speed scene, the present invention adopts the mode of diversity transmission, promptly utilizes a plurality of effective RRU to carry out the transmission of downstream signal simultaneously, sends the receive diversity that downstream signals institute can bring and gains so that UE obtains many RRU.In addition, consider that present UE can effectively follow the tracks of the carrier frequency of multipath signal with identical Doppler frequency deviation, so can detect downstream signal comparatively accurately, therefore, the present invention will go up the downstream signal that sends to each RRU respectively and carry out compensate of frequency deviation at different RRU before the transmission of carrying out downstream signal, can have identical Doppler frequency deviation so that each RRU goes up after the downstream signal that sends arrives the UE place, thereby can improve the detection performance of UE downstream signal.Concrete, the present invention will determine effective RRU of UE according to the received signal of each RRU to the upward signal of any one up channel of UE, only send the downstream signal of UE by these effective RRU at down direction; Determine that each effective RRU goes up the Doppler frequency deviation of the upward signal of UE; Determine downstream signal to be sent on any one downstream signal of UE, all effective RRU need this downstream signal is sent to UE; Before each RRU sends to UE with the downstream signal of the down channel of UE, the downstream signal of each RRU is carried out frequency deviation pre-compensation, have identical Doppler frequency deviation when making the downstream signal of each RRU arrive UE through frequency deviation pre-compensation.The diversity sending method of the high speed scene downstream signal that the present invention proposes had both solved the high speed scene from the multispectral frequency deviation problem inequality of reining in of the downstream signal of different RRUs, can make UE obtain the receive diversity gain again.The present invention will be described in detail below by two specific embodiments of the present invention.

The embodiment of the invention one is to realize on the basis of the frequency deviation pre-compensation method of existing downstream signal.Embodiment one determines effective RRU of UE according to the received signal of each RRU to the upward signal of any one up channel of UE, only sends the downstream signal of UE by these effective RRU at down direction.Need among the embodiment one to determine that each effective RRU goes up the Doppler frequency deviation of the upward signal of UE; And downstream signal to be sent on any one down channel of definite UE, all effective RRU need this downstream signal is sent to UE.Before each RRU sends to UE with the downstream signal of the down channel of UE, the downstream signal of each RRU is carried out frequency deviation pre-compensation, have identical Doppler frequency deviation when making the downstream signal of each RRU arrive UE through frequency deviation pre-compensation.

Before the idiographic flow of introducing embodiment one in detail, describe earlier the derivation of method of determining the accumulative total compensate of frequency deviation amount of other any one effective RRU based on an effective RRU in detail.

The carrier frequency of supposing NODEB and UE is respectively f _NodeBAnd f _UEWherein, any two RRU that receive the UE upward signal go up because the Doppler frequency deviation of the upward signal that the high-speed mobile of UE causes is respectively: Δ f _{UE, 1}With Δ f _{UE, 2}These two RRU that the NODEB estimation obtains go up the frequency deviation of the upward signal of UE and use Δ f respectively ₁With Δ f ₂Expression.These two frequency deviations are calculated according to following formula:

Δf ₁＝f _UE+Δf _UE，1-f _NodeB (1)

Δf ₂＝f _UE+Δf _UE，2-f _NodeB (2)

Therefore, can obtain:

Δf ₁-Δf ₂＝Δf _UE，1-Δf _UE，2 (3)

When the accumulative total compensate of frequency deviation amount of first RRU is u ₁The time, the frequency the when downstream signal of this RRU arrives UE is:

f ₁＝f _NodeB-u ₁+Δf _UE，1 (4)

If the accumulative total compensate of frequency deviation amount of second RRU is u ₂, the frequency the when downstream signal of this RRU arrives UE is:

f ₂＝f _NodeB-u ₂+Δf _UE，2 (5)

Has identical frequency when arriving UE, then for the downstream signal that makes two RRU

f ₁＝f ₂ (6)

Can obtain following formula by (4) (5) and (6):

u ₂＝u ₁+Δf _UE，2-Δf _UE，1 (7)

Can further obtain by formula (3) and (7):

u ₂＝u ₁+Δf ₂-Δf ₁ (8)

NODEB can calculate the accumulative total compensate of frequency deviation amount u of benchmark RRU according to the method in the existing document ₁Frequency deviation Δ f with benchmark RRU ₁, and calculate the frequency deviation Δ f of any one other effective RRU according to the method in the existing document ₂, can calculate the accumulative total compensate of frequency deviation amount u of any one other effective RRU then according to formula (8) ₂

Fig. 2 is the flow chart of the embodiment of the invention one, and as shown in Figure 2, this embodiment one mainly comprises:

Step 201, in current subframe, all RRU effectively far away of UE are determined in the base station, and determine each described effective RRU go up the Doppler frequency deviation p of the upward signal of this UE (i, n).

Wherein, i is the numbering of arbitrary described effective RRU, and n is the numbering of current subframe.

This step in any subframe " n ", is determined all effective RRU of UE according to each RRU to the received signal of the upward signal of any one up channel of UE, and determines that each effective RRU goes up the Doppler frequency deviation of the upward signal of UE.The method of determining the Doppler frequency deviation of the method for effective RRU and the upward signal that definite each effective RRU goes up UE sees also existing document, does not repeat them here.

Here, the upward signal of the arbitrary up channel of the UE that the base station receives according to i RRU in current subframe, determine that the Doppler frequency deviation of the upward signal of UE on this RRU is: p (i, n); (i, definite method n) does not repeat them here for it be known to those skilled in the art that Doppler frequency deviation p.

The power that each described effective RRU goes up the upward signal of UE is calculated in step 202, base station, select prominent effective RRU as benchmark RRU, described Doppler frequency deviation p (l according to described benchmark RRU, n), determine the accumulative total compensate of frequency deviation amount u (l of described benchmark RRU, n), wherein, l is the numbering of described benchmark RRU.

This step, in any subframe " n ", calculate the power that each effective RRU goes up the upward signal of UE, select the strongest RRU of power as benchmark RRU, and the accumulative total compensate of frequency deviation amount that is adopted when determining to send the downstream signal of any one down channel of UE by this RRU.The method of calculating the accumulative total compensate of frequency deviation amount of this RRU sees also pertinent literature, does not repeat them here.

Here, suppose that for any one up channel of UE, " l " individual RRU receives the power maximum of upward signal of this up channel of UE in the n subframe; " m " individual RRU receives any one RRU except that " l " individual RRU among the RRU of upward signal of this up channel of UE.

Suppose to be sent in " n+d by " l " individual RRU _Ul" during the downstream signal of any one down channel of subframe UE, close for the frequency of the upward signal that makes UE to the carrier frequency of base station, make the frequency deviation of UE upward signal trend towards 0, at " n+d _Ul" downstream signal that sends on any one down channel of UE of subframe carries out frequency deviation pre-compensation.Suppose to adopt the frequency deviation pre-compensation method in the existing document, the accumulative total compensate of frequency deviation amount of " n " subframe that calculates according to the frequency offset estimation result of the individual RRU of " n " subframe " l " is: and u (l, n).

Step 203, according to the accumulative total compensate of frequency deviation amount u (l of described benchmark RRU, n) and described Doppler frequency deviation p (i, n), according to u (m, n)=u (l, n)+and p (m, n)-p (l, n), determine the accumulative total compensate of frequency deviation amount u (m of each the effective RRU except that described benchmark RRU, n), wherein, m is the numbering of the arbitrary effective RRU except that described benchmark RRU.

This step is based on the accumulative total compensate of frequency deviation amount u (l of benchmark RRU, n), to other the accumulative total compensate of frequency deviation amount u (m of each effective RRU, n) determine, so that the frequency deviation of the downstream signal that each effective RRU sends from other is identical with the frequency deviation of the downstream signal that sends from benchmark RRU, thereby be convenient to of the detection of UE side to down receiving signal.

Step 204, at n+d _UlSubframe, at each described effective RRU, according to the accumulative total compensate of frequency deviation amount u of this RRU (i, n), to this effective RRU at n+d _UlThe downstream signal of this UE that subframe sends carries out frequency deviation pre-compensation, utilizes this effective RRU will send to described UE through the downstream signal behind the frequency deviation pre-compensation, wherein, and d _UlBe 201, the 202 and 203 needed times of base station execution in step.

The accumulative total compensate of frequency deviation amount that this step is utilized each the effective RRU that calculates in any subframe " n " to this RRU at " n+d _Ul" downstream signal of any one down channel of this UE of sending of subframe carries out frequency deviation pre-compensation.

Here, the frequency deviation pre-compensation method of considering existing downstream signal is only applicable to single channel RRU, and be not suitable for multichannel RRU, therefore can distinguish single channel RRU when carrying out frequency deviation pre-compensation in this step and multichannel RRU correspondingly handles respectively, so that the present invention is applicable to single channel RRU and multichannel RRU simultaneously.Particularly, the frequency deviation pre-compensation method in this step can adopt following method to realize:

When the effective RRU that carries out frequency deviation pre-compensation is benchmark RRU, can adopt following frequency deviation pre-compensation method:

As benchmark RRU (i.e. " l " individual RRU) when being single channel RRU, can calculate the downstream signal of this RRU according to the method in the existing document through frequency deviation pre-compensation.According to the method in the existing document, the computing formula of the downstream signal of the process frequency deviation pre-compensation of this RRU is as follows:

When benchmark RRU is single channel RRU, the base station according to $S(l,n+d_{\mathrm{ul}},k)=s(n+d_{\mathrm{ul}},k)\·e^{-j2\mathrm{\π}\·u(l,n)\·(k-1)\·\mathrm{SF}\·T_c},$ Downstream signal s (n+d to described UE _Ul, k) carry out frequency deviation pre-compensation, obtain downstream signal S (l, n+d behind the frequency deviation pre-compensation _Ul, k).

Wherein, k is the numbering of the arbitrary symbol in the symbol sebolic addressing of described downstream signal, and SF represents the spreading factor of the down channel of described UE, T _cThe duration of a chip of expression.

Suppose at " n+d _Ul" downstream signal of any one down channel of the UE that sends by " l " individual RRU of subframe is:

s(n+d _ul，k)＝A(n+d _ul，k)C(n+d _ul，k) (9)

C (n+d _Ul, k) be illustrated in " n+d _Ul" k symbol in the symbol sebolic addressing that carries on any one down channel of subframe UE, this symbol sebolic addressing is to modulate through the bit sequence that the UE coding is obtained to obtain; A (n+d _Ul, k) be the emission amplitude of this symbol sebolic addressing, determine according to the transmitting power of this symbol sebolic addressing.The transmitting power of this symbol sebolic addressing is determined according to DLPC (descending power control) method.

When benchmark RRU was multichannel RRU, the present invention proposed: this RRU according to the upward signal of its described UE that receives determine described UE down beam shaping weight vector w (l, n), according to $S(l,n+d_{\mathrm{ul}},k)=w(l,n)s(n+d_{\mathrm{ul}},k)\·e^{-j2\mathrm{\π}\·u(l,n)\·(k-1)\·\mathrm{SF}\·T_c},$ Downstream signal s (n+d to described UE _Ul, k) carry out frequency deviation pre-compensation, obtain downstream signal S (l, n+d behind the frequency deviation pre-compensation _Ul, k).

Wherein, w (l, n)=[w (l, n, 1), w (l, n, 2) ..., w (l, n, N _{Ant, l})], v=1 ..., N _{Ant, l}W (l, n v) represents v the component of the determined wave beam forming weight vector of received signal of upward signal of any one up channel of the UE that the base station receives in the n subframe according to this RRU, the beam shape-endowing weight value of v the passage of this RRU of this representation in components; N _{Ant, l}Represent the number of active lanes that this RRU comprises, S (l, n+d _Ul, k)=[S (l, n+d _Ul, k, 1), S (l, n+d _Ul, k, 2) ..., S (l, n+d _Ul, k, N _{Ant, l})], $S(l,n+d_{\mathrm{ul}},k,v)=w(l,n,v)s(n+d_{\mathrm{ul}},k)\·e^{-j2\mathrm{\π}\·u(l,n)\·(k-1)\·\mathrm{SF}\·T_c},$ K is the numbering of the arbitrary symbol in the symbol sebolic addressing of described downstream signal, and SF represents the spreading factor of the down channel of described UE, T _cThe duration of a chip of expression.

As the effective RRU that carries out frequency deviation pre-compensation during for the arbitrary effective RRU except that benchmark RRU, the present invention's proposition: can adopt following frequency deviation pre-compensation method:

When described effective RRU is single channel RRU, according to $S(m,n+d_{\mathrm{ul}},k)=s(n+d_{\mathrm{ul}},k)\·e^{-j2\mathrm{\π}\·u(m,n)\·(k-1)\·\mathrm{SF}\·T_c},$ Downstream signal s (n+d to described UE _Ul, k) carry out frequency deviation pre-compensation, obtain downstream signal S (m, n+d behind the frequency deviation pre-compensation _Ul, k), wherein, k is the numbering of the arbitrary symbol in the symbol sebolic addressing of described downstream signal, and SF represents the spreading factor of the down channel of described UE, and Tc represents the duration of a chip.

When described effective RRU is arbitrary described effective RRU except that described benchmark RRU, and when being multichannel RRU, this RRU according to the upward signal of its described UE that receives determine described UE down beam shaping weight vector w (m, n), according to $S(m,n+d_{\mathrm{ul}},k)=w(m,n)s(n+d_{\mathrm{ul}},k)\·e^{-j2\mathrm{\π}\·u(m,n)\·(k-1)\·\mathrm{SF}\·T_c},$ Downstream signal s (n+d to described UE _Ul, k) carry out frequency deviation pre-compensation, obtain downstream signal S (m, n+d behind the frequency deviation pre-compensation _Ul, k),

Wherein, w (m, n)=[w (m, n, 1), w (m, n, 2) ..., w (m, n, N _{Ant, m})], w (m, n v) represents v the component of the determined wave beam forming weight vector of received signal of upward signal of any one up channel of the UE that the base station receives in the n subframe according to this RRU, the beam shape-endowing weight value of v the passage of this RRU of this representation in components; V=1 ..., N _{Ant, m}, N _{Ant, l}Represent the number of active lanes that this RRU comprises, S (m, n+d _Ul, k)=[S (m, n+d _Ul, k, 1), S (m, n+d _Ul, k, 2) ..., S (m, n+d _Ul, k, N _{Ant, m})], $S(m,n+d_{\mathrm{ul}},k,v)=w(m,n,v)s(n+d_{\mathrm{ul}},k)\·e^{-j2\mathrm{\π}\·u(m,n)\·(k-1)\·\mathrm{SF}\·T_c},$ K is the numbering of the arbitrary symbol in the symbol sebolic addressing of described downstream signal, and SF represents the spreading factor of the down channel of described UE, T _cThe duration of a chip of expression.

The existing frequency deviation pre-compensation method that is based on the foregoing description one realizes that its purpose is to avoid the UE downstream signal that UE receives when taking place to switch between the pole saltus step of twice frequency deviation to occur.In actual applications, can also adopt additive method to avoid occurring the situation of above-mentioned twice frequency deviation saltus step, be elaborated below by the embodiment of the invention two.

The sending method of the another kind of downstream signal that the embodiment of the invention two proposes sends the downstream signal of any one down channel of UE by all effective RRU of UE.This method determines to receive the strongest RRU of upward signal power of UE up channel, is benchmark with this RRU, when predicting the downstream signal of any one down channel that passes through this RRU transmission UE, and the Doppler frequency deviation when this downstream signal arrives UE; And prediction is when sending the downstream signal of this down channel of UE by any one other effective RRU, the Doppler frequency deviation when this downstream signal arrives UE; Doppler frequency deviation when the Doppler frequency deviation when arriving UE for the downstream signal that makes any one other effective RRU arrives UE with the downstream signal of this benchmark RRU is identical, calculates the frequency deviation pre-compensation amount that any one other effective RRU need carry out.When sending the downstream signal of UE for the first time, when sending the downstream signal of UE, do not carry out frequency deviation pre-compensation by benchmark RRU.That is: the frequency deviation pre-compensation amount is 0.After sending the downstream signal of UE for the first time,, still do not carry out frequency deviation pre-compensation when sending the downstream signal of UE by benchmark RRU as long as the switching between the pole does not take place UE.That is: the frequency deviation pre-compensation amount is 0.But, need carry out frequency deviation pre-compensation to this downstream signal according to the frequency deviation pre-compensation amount of this RRU when other effective RRU sends the downstream signal of any one subframe of this UE by any one.When switching between the pole takes place UE when the area of coverage of a pole enters the area of coverage of another pole (that is: UE from), variation has taken place in the pole at benchmark RRU place before and after switching.After pole is switched, Doppler frequency deviation when the downstream signal of benchmark RRU arrives UE with switch before Doppler frequency deviation during the downstream signal arrival UE of benchmark RRU identical, need carry out frequency deviation pre-compensation to the downstream signal of benchmark RRU after switching, calculate the frequency deviation pre-compensation amount of benchmark RRU after switching, adopt this frequency deviation pre-compensation amount that the downstream signal of this RRU is carried out frequency deviation pre-compensation, make when the downstream signal of benchmark RRU arrives UE after switching frequency deviation with switch before the downstream signal arrival UE of benchmark RRU the time frequency deviation identical.Then, be benchmark with benchmark RRU after switching again, the frequency deviation pre-compensation amount of any one other effective RRU after calculate switching, the Doppler frequency deviation when making the downstream signal of any one other effective RRU arrive UE and this switchings Doppler frequency deviation during the downstream signal arrival UE of benchmark RRU afterwards are identical.After switching between the pole takes place UE for the first time, need carry out frequency deviation pre-compensation to the downstream signal of the UE that sends by benchmark RRU.Whenever the switching that takes place between the pole, need recomputate the frequency deviation pre-compensation amount of the downstream signal that sends by the benchmark RRU after switching.Said method can effectively be followed the tracks of the carrier frequency of the multipath signal with identical Doppler frequency deviation based on UE.

Fig. 3 is the flow chart of the embodiment of the invention two, and as shown in Figure 3, the embodiment of the invention two may further comprise the steps:

Step 301, in current subframe, all effective RRU of UE are determined in the base station, and determine that each described effective RRU goes up the Doppler frequency deviation p (i of the upward signal of this UE _n, n).

Wherein, i _nBe the numbering of arbitrary described effective RRU of determining in the n subframe, n is the numbering of current subframe.

This step in any subframe " n ", is determined all effective RRU of UE according to each RRU to the received signal of the upward signal of any one up channel of UE, and determines that each effective RRU goes up the Doppler frequency deviation of the upward signal of UE.The method of determining the Doppler frequency deviation of the method for effective RRU and the upward signal that definite each effective RRU goes up UE sees also existing document.

The power that each described effective RRU goes up the upward signal of UE is calculated in step 302, base station, selects prominent effective RRU as benchmark RRU, according to the described Doppler frequency deviation p (l of described benchmark RRU _n, n) and the frequency deviation pre-compensation amount u (l of the benchmark RRU that determines in the n-1 subframe _N-1, n-1) with Doppler frequency deviation p (l _N-1, n-1), calculate the frequency deviation pre-compensation amount u (l of the described benchmark RRU that determines in the n subframe _n, n).

In this step, in any subframe " n ", calculate the power that each effective RRU goes up the upward signal of UE, select the strongest RRU of power as benchmark RRU, and the frequency deviation pre-compensation amount that is adopted when determining to send the downstream signal of any one down channel of UE by this RRU.The method of calculating the frequency deviation pre-compensation amount of this RRU sees also hereinafter.

Wherein, l _nBe the numbering of the benchmark RRU that determines in the n subframe, l _N-1It is the numbering of the benchmark RRU that determines in the n-1 subframe.

Here, the frequency deviation pre-compensation amount u (l of the described benchmark RRU that determines in the described calculating n subframe _n, n) can for:

When n subframe is first sub-frame of uplink after described UE inserts, according to u (l _n, n)=0 calculate described frequency deviation pre-compensation amount u (l _n, n);

When the n subframe is that described UE is when inserting any one sub-frame of uplink except that first sub-frame of uplink of back, if the switching of described UE between n subframe generation pole is (that is: at the benchmark RRU of " n-1 " subframe " l _N-1" and the benchmark RRU " l of " n " subframe _n" not on same pole), then according to u (l _n, n)=u (l _N-1, n-1)+p (l _n, n)-p (l _N-1, n-1) calculate described frequency deviation pre-compensation amount u (l _n, n), otherwise (that is: at the benchmark RRU of " n-1 " subframe " l _N-1" and the benchmark RRU " l of " n " subframe _n" on same pole) according to u (l _n, n)=u (l _N-1, n-1) calculate described frequency deviation pre-compensation amount u (l _n, n).

In above-mentioned steps, when second sub-frame of uplink after the n subframe is described UE access or any one sub-frame of uplink after this subframe, whether the needs consideration switching between the pole takes place in the n subframe, if the switching between the pole has taken place, and then need be according to u (l _n, n)=u (l _N-1, n-1)+p (l _n, n)-p (l _N-1, n-1) the frequency deviation pre-compensation amount u (l on the benchmark RRU of calculating in the n subframe _n, n), promptly need to determine the frequency deviation pre-compensation amount of determined new benchmark RRU in the n subframe so that overcome the problem of the inclined to one side saltus step of two frequencys multiplication that when taking place to switch between pole, is occurred, and if switching between the pole does not take place, then according to u (l _n, n)=u (l _N-1, n-1), calculate frequency deviation pre-compensation amount u (l _n, n), that is to say, for two benchmark RRU of consecutive frame,, then do not need to change the frequency deviation pre-compensation amount of benchmark RRU if belong to same pole.

Step 303, according to the frequency deviation pre-compensation amount u (l of described benchmark RRU _n, n) with described Doppler frequency deviation p (i _n, n), according to u (m _n, n)=u (l _n, n)+p (m _n, n)-p (l _n, n), calculate the frequency deviation pre-compensation amount u (m of each the effective RRU except that described benchmark RRU in determined all the effective RRU of n subframe _n, n), wherein, m _nNumbering for the arbitrary effective RRU except that described benchmark RRU.

This step is used for based on benchmark RRU, determines the frequency deviation pre-compensation amount u (m of other effective RRU of UE _n, n).

Step 304, at n+d _UlSubframe is at determined each the effective RRU of n subframe, according to the frequency deviation pre-compensation amount u (i of this RRU _n, n), to this RRU at n+d _UlThe downstream signal that subframe need send to described UE carries out frequency deviation pre-compensation, utilizes this RRU will send to described UE through the downstream signal behind the frequency deviation pre-compensation, wherein, and d _UlBe 301, the 302 and 303 needed times of base station execution in step.

The frequency deviation pre-compensation amount that this step is utilized each the effective RRU that calculates in any subframe " n " to this RRU at " n+d _Ul" downstream signal of any one down channel of this UE of sending of subframe carries out frequency deviation pre-compensation.

Can be by this step so that the downstream signal that utilizes different effectively RRU to send to same UE can obtain identical Doppler frequency deviation after arriving this UE, so that this UE can effectively follow the tracks of the carrier frequency of the multipath signal with identical Doppler frequency deviation, thereby can improve the detection performance of UE side to down receiving signal.

In order to make embodiment two be applicable to single channel RRU and multichannel RRU simultaneously, the frequency deviation pre-compensation in this step can for:

When described effective RRU is single channel RRU, the base station according to $S(i_n,n+d_{\mathrm{ul}},k)=s(n+d_{\mathrm{ul}},k)\·e^{-j2\mathrm{\π}\·u(i_n,n)\·(k-1)\·\mathrm{SF}\·T_c},$ Downstream signal s (n+d to described UE _Ul, k) carry out frequency deviation pre-compensation, obtain the downstream signal S (i behind the frequency deviation pre-compensation _n, n+d _Ul, k), wherein, k is the numbering of the arbitrary symbol in the symbol sebolic addressing of described downstream signal, SF represents the spreading factor of the down channel of described UE, T _cThe duration of a chip of expression;

When described effective RRU was multichannel RRU, the down beam shaping weight vector w (i of described UE was determined in the base station according to the upward signal of its described UE that receives _n, n), according to $S(i_n,n+d_{\mathrm{ul}},k)=w(i_n,n)s(n+d_{\mathrm{ul}},k)\·e^{-j2\mathrm{\π}\·u(i_n,n)\·(k-1)\·\mathrm{SF}\·T_c},$ Downstream signal s (n+d to described UE _Ul, k) carry out frequency deviation pre-compensation, obtain the downstream signal S (i behind the frequency deviation pre-compensation _n, n+d _Ul, k), wherein, $w(i_n,n)=[w(i_n,n,1),w(i_n,n,2),......,w(i_n,n,N_{\mathrm{ant},i_n})],$ W (m, n v) represent the beam shape-endowing weight value of v the passage of this RRU, $v=1,...,N_{\mathrm{ant},i_n},$

Represent the number of active lanes that this RRU comprises, $S(i_n,n+d_{\mathrm{ul}},k)=[S(i_n,n+d_{\mathrm{ul}},k,1),S(i_n,n+d_{\mathrm{ul},}k,2),......,S(i_n,n+d_{\mathrm{ul}},k,N_{\mathrm{ant},i_n})],$ $S(i_n,n+d_{\mathrm{ul}},k,v)=w(i_n,n,v)s(n+d_{\mathrm{ul}},k)\·e^{-j2\mathrm{\π}\·u(i_n,n)\·(k-1)\·\mathrm{SF}\·T_c},$ K is the numbering of the arbitrary symbol in the symbol sebolic addressing of described downstream signal, and SF represents the spreading factor of the down channel of described UE, T _cThe duration of a chip of expression.

In this step, determine the down beam shaping weight vector w (i of described UE _n, concrete grammar n) does not repeat them here for it be known to those skilled in the art that.

By above-mentioned two specific embodiments, as can be seen, the present invention carries out the transmission of downstream signal by the mode that adopts diversity transmission in a plurality of effective RRU, and before each RRU sends to UE with the downstream signal of UE, downstream signal to each RRU carries out frequency deviation pre-compensation, the feasible downstream signal that issues from all effective RRU has identical Doppler frequency deviation when arriving UE, thereby effectively overcome because inequality and UE side down receiving signal is detected Effect on Performance, can make UE obtain many RRU simultaneously and send the receive diversity gain that is brought from the multispectral frequency deviation of reining in of the downstream signal of different RRUs.

In addition, the downstream signal that the present invention sends on effective RRU to each carries out compensate of frequency deviation, and when utilizing downstream signal after each effective RRU sends compensate of frequency deviation, all distinguish single channel RRU and multichannel RRU correspondingly handles respectively, therefore, the present invention will be applicable to single channel RRU and multichannel RRU simultaneously.

In sum, more than be preferred embodiment of the present invention only, be not to be used to limit protection scope of the present invention.Within the spirit and principles in the present invention all, any modification of being done, be equal to replacement, improvement etc., all should be included within protection scope of the present invention.

Claims (5)

1. the sending method of a downstream signal is characterized in that, this method may further comprise the steps:

A, in current subframe, all effective remote radio unit (RRU) RRU of user equipment (UE) are determined in the base station, and determine that each described effective RRU goes up the Doppler frequency deviation p (i of the upward signal of this UE, n), wherein, i is the numbering of arbitrary described effective RRU, and n is the numbering of current subframe;

The power that each described effective RRU goes up the upward signal of UE is calculated in b, base station, select prominent effective RRU as benchmark RRU, described Doppler frequency deviation p (l according to described benchmark RRU, n), determine the accumulative total compensate of frequency deviation amount u (l of described benchmark RRU, n), wherein, l is the numbering of described benchmark RRU;

C, base station are according to the accumulative total compensate of frequency deviation amount u (l of described benchmark RRU, n) and described Doppler frequency deviation p (i, n), according to u (m, n)=u (l, n)+and p (m, n)-p (l, n), determine the accumulative total compensate of frequency deviation amount u (m of each the effective RRU except that described benchmark RRU, n), wherein, m is the numbering of the arbitrary effective RRU except that described benchmark RRU;

D, at n+d _UlSubframe, base station be at each described effective RRU, according to the accumulative total compensate of frequency deviation amount u of this RRU (i, n), to this effective RRU at n+d _UlThe downstream signal of this UE that subframe sends carries out frequency deviation pre-compensation, utilizes this effective RRU will send to described UE through the downstream signal behind the frequency deviation pre-compensation, wherein, and d _UlBe base station execution in step a, b and needed time of c.

2. method according to claim 1 is characterized in that, the frequency deviation pre-compensation in the described steps d is:

When described effective RRU is described benchmark RRU, and when being single channel RRU, the base station according to $S(l,n+d_{\mathrm{ul}},k)=s(n+d_{\mathrm{ul}},k)\·e^{-j2\mathrm{\π}\·u(l,n)\·(k-1)\·\mathrm{SF}\·T_c},$ Downstream signal s (n+d to described UE _Ul, k) carry out frequency deviation pre-compensation, obtain downstream signal S (l, n+d behind the frequency deviation pre-compensation _Ul, k), wherein, k is the numbering of the arbitrary symbol in the symbol sebolic addressing of described downstream signal, SF represents the spreading factor of the down channel of described UE, T _cThe duration of a chip of expression;

When described effective RRU is described benchmark RRU, and when being multichannel RRU, the base station determine described UE down beam shaping weight vector w (l, n), according to $S(l,n+d_{\mathrm{ul}},k)=w(l,n)s(n+d_{\mathrm{ul}},k)\·e^{-j2\mathrm{\π}\·u(l,n)\·(k-1)\·\mathrm{SF}\·T_c},$ Downstream signal s (n+d to described UE _Ul, k) carry out frequency deviation pre-compensation, obtain downstream signal S (l, n+d behind the frequency deviation pre-compensation _Ul, k), wherein, w (l, n)=[w (l, n, 1), w (l, n, 2) ..., w (l, n, N _{Ant, l})], v=1 ..., N _{Ant, l}, (l, n v) represent the beam shape-endowing weight value of v the passage of this RRU, N to w _{Ant, l}Represent the number of active lanes that this RRU comprises, S (l, n+d _Ul, k)=[S (l, n+d _Ul, k, 1), S (l, n+d _Ul, k, 2) ..., S (l, n+d _Ul, k, N _{Ant, l})], $S(l,n+d_{\mathrm{ul}},k,v)=w(l,n,v)s(n+d_{\mathrm{ul}},k)\·e^{-j2\mathrm{\π}\·u(l,n)\·(k-1)\·\mathrm{SF}\·T_c},$ K is the numbering of the arbitrary symbol in the symbol sebolic addressing of described downstream signal, and SF represents the spreading factor of the down channel of described UE, T _cThe duration of a chip of expression;

When described effective RRU is arbitrary described effective RRU except that described benchmark RRU, and when being single channel RRU, the base station according to $S(m,n+d_{\mathrm{ul}},k)=s(n+d_{\mathrm{ul}},k)\·e^{-j2\mathrm{\π}\·u(m,n)\·(k-1)\·\mathrm{SF}\·T_c},$ Downstream signal s (n+d to described UE _Ul, k) carry out frequency deviation pre-compensation, obtain downstream signal S (m, n+d behind the frequency deviation pre-compensation _Ul, k), wherein, k is the numbering of the arbitrary symbol in the symbol sebolic addressing of described downstream signal, SF represents the spreading factor of the down channel of described UE, T _cThe duration of a chip of expression;

When described effective RRU is arbitrary described effective RRU except that described benchmark RRU, and when being multichannel RRU, the base station determine described UE down beam shaping weight vector w (m, n), according to $S(m,n+d_{\mathrm{ul}},k)=w(m,n)s(n+d_{\mathrm{ul}},k)\·e^{-j2\mathrm{\π}\·u(m,n)\·(k-1)\·\mathrm{SF}\·T_c},$ Downstream signal s (n+d to described UE _Ul, k) carry out frequency deviation pre-compensation, obtain downstream signal S (m, n+d behind the frequency deviation pre-compensation _Ul, k), wherein, w (m, n)=[w (m, n, 1), w (m, n, 2) ..., w (m, n, N _{Ant, m})], w (m, n v) represent the beam shape-endowing weight value of v the passage of this RRU, v=1 ..., N _{Ant, m}, N _{Ant, m}Represent the number of active lanes that this RRU comprises, S (m, n+d _Ul, k)=[S (m, n+d _Ul, k, 1), S (m, n+d _Ul, k, 2) ..., S (m, n+d _Ul, k, N _{Ant, m})], $S(m,n+d_{\mathrm{ul}},k,v)=w(m,n,v)s(n+d_{\mathrm{ul}},k)\·e^{-j2\mathrm{\π}\·u(m,n)\·(k-1)\·\mathrm{SF}\·T_c},$ K is the numbering of the arbitrary symbol in the symbol sebolic addressing of described downstream signal, and SF represents the spreading factor of the down channel of described UE, T _cThe duration of a chip of expression.

3. the sending method of a downstream signal is characterized in that, this method may further comprise the steps:

A, in current subframe, all effective remote radio unit (RRU) RRU of user equipment (UE) are determined in the base station, and determine that each described effective RRU goes up the Doppler frequency deviation p (i of the upward signal of this UE _n, n), wherein, i _nBe the numbering of arbitrary described effective RRU of determining in the n subframe, n is the numbering of current subframe;

The power that each described effective RRU goes up the upward signal of UE is calculated in b, base station, selects prominent effective RRU as benchmark RRU, according to the described Doppler frequency deviation p (l of described benchmark RRU _n, n) and the frequency deviation pre-compensation amount u (l of the benchmark RRU that determines in the n-1 subframe _N-1, n-1) with Doppler frequency deviation p (l _N-1, n-1), calculate the frequency deviation pre-compensation amount u (l of the described benchmark RRU that determines in the n subframe _n, n), wherein, l _nBe the numbering of the benchmark RRU that determines in the n subframe, l _N-1It is the numbering of the benchmark RRU that determines in the n-1 subframe;

C, according to the frequency deviation pre-compensation amount u (l of described benchmark RRU _n, n) with described Doppler frequency deviation p (i _n, n), according to u (m _n, n)=u (l _n, n)+p (m _n, n)-p (l _n, n), calculate the frequency deviation pre-compensation amount u (m of each the effective RRU except that described benchmark RRU in determined all the effective RRU of n subframe _n, n), wherein, m _nNumbering for the arbitrary effective RRU except that described benchmark RRU;

D, at n+d _UlSubframe is at determined each the effective RRU of n subframe, according to the frequency deviation pre-compensation amount u (i of this RRU _n, n), to this RRU at n+d _UlThe downstream signal that subframe need send to described UE carries out frequency deviation pre-compensation, utilizes this RRU will send to described UE through the downstream signal behind the frequency deviation pre-compensation, wherein, and d _UlBe base station execution in step a, b and needed time of c.

4. method according to claim 3 is characterized in that, calculates the frequency deviation pre-compensation amount u (l of the described benchmark RRU that determines in the n subframe among the described step b _n, n) be:

When n subframe is first sub-frame of uplink after described UE inserts, according to u (l _n, n)=0 calculate described frequency deviation pre-compensation amount u (l _n, n);

When n subframe is described UE when inserting any one sub-frame of uplink except that first sub-frame of uplink of back, if the switching of described UE between n subframe generation pole, then according to u (l _n, n)=u (l _N-1, n-1)+p (l _n, n)-p (l _N-1, n-1) calculate described frequency deviation pre-compensation amount u (l _n, n), otherwise according to u (l _n, n)=u (l _N-1, n-1) calculate described frequency deviation pre-compensation amount u (l _n, n).

5. method according to claim 3 is characterized in that, the described frequency deviation pre-compensation in the steps d is:

When described effective RRU is single channel RRU, the base station according to $S(i_n,n+d_{\mathrm{ul}},k)=s(n+d_{\mathrm{ul}},k)\·e^{-j2\mathrm{\π}\·u(i_n,n)\·(k-1)\·\mathrm{SF}\·T_c},$ Downstream signal s (n+d to described UE _Ul, k) carry out frequency deviation pre-compensation, obtain the downstream signal S (i behind the frequency deviation pre-compensation _n, n+d _Ul, k), wherein, k is the numbering of the arbitrary symbol in the symbol sebolic addressing of described downstream signal, SF represents the spreading factor of the down channel of described UE, T _cThe duration of a chip of expression;

When described effective RRU was multichannel RRU, the down beam shaping weight vector w (i of described UE was determined in the base station _n, n), according to $S(i_n,n+d_{\mathrm{ul}},k)=w(i_n,n)s(n+d_{\mathrm{ul}},k)\·e^{-j2\mathrm{\π}\·u(i_n,n)\·(k-1)\·\mathrm{SF}\·T_c},$ Downstream signal s (n+d to described UE _Ul, k) carry out frequency deviation pre-compensation, obtain the downstream signal S (i behind the frequency deviation pre-compensation _n, n+d _Ul, k), wherein, $w(i_n,n)=[w(i_n,n,1),w(i_n,n,2),......,w(i_n,n,N_{{\mathrm{ant},i}_n})],$ W (i _n, n v) represents the beam shape-endowing weight value of v the passage of this RRU,

Represent the number of active lanes that this RRU comprises, $S(i_n,n+d_{\mathrm{ul}},k)=[S(i_n,n+d_{\mathrm{ul}},k,1),S(i_n,n+d_{\mathrm{ul}},k,2),......,S(i_n,n+d_{\mathrm{ul}},k,N_{\mathrm{ant},i_n})],$ $S(i_n,n+d_{\mathrm{ul}},k,v)=w(i_n,n,v)s(n+d_{\mathrm{ul}},k)\·e^{-j2\mathrm{\π}\·u(i_n,n)\·(k-1)\·\mathrm{SF}\·T_c},$ K is the numbering of the arbitrary symbol in the symbol sebolic addressing of described downstream signal, and SF represents the spreading factor of the down channel of described UE, T _cThe duration of a chip of expression.

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