CN201504233U - Code Division Multiple Access Multipath Synchronous Demodulation Diversity Receiver - Google Patents

Abstract

The CDMA multipath synchronous demodulation diversity receiver includes three first QAM coherent demodulators (21), second QAM coherent demodulators (22), third QAM coherent demodulator (23), the first delay device (24), the second delay device (25) for adjusting multipath time delay, the first adder (M for I path three-path signal superimposition ₂₆ ), the second adder (M ₂₇ ) used for the superposition of the three-path signals of the Q path, the first multiplier (M ₂₈ ) used for the descrambling of the combined signal of the I path, and the descrambling of the combined signal used for the Q path The second multiplier (M ₂₉ ); can be used for mobile communication code division multiple access reception, the device first restores the independent three-path local coherent carrier, used for carrier separation and demodulation of multi-path signals, and then passes through two delayers Delay the two-path signals to achieve the synchronization of the three-path signals, and descramble after combining the three-path signals.

Description

CDMA multipath synchronous demodulation diversity receiver

Technical field

The utility model relates to a kind of CDMA multipath signal carrier coherent demodulating Rake (RAKE) receiver, can be used for the cdma system down link signal receives, realize the merging of multipath collection of letters energy expeditiously, can increase substantially the power utilization and the receiver signal to noise ratio of down channel multipath transmisstion signal, belong to the mobile communication technology field.

Background technology

Traditional rake receiver (CLRAKE) is the element of CDMA receiver.Utilize the CLRAKE receiver can realize the separation of receiving terminal multipath signal in the mobile communication wireless communication environments, time delay adjustment and three basic processes of stack combinations, thereby realize the diversity reception of multipath transmisstion energy, improve the collection of letters signal to noise ratio of receiver and a power utilization of base station.Yet used CLRAKE receiver is all realized on base band, the influence of phase difference between the multipath signal carrier of not considering to receive.In the realization of CDMA downstream signal receiver, should adopt the coherent demodulation mode.Owing to have phase difference, the road coherent carrier C that recovers in the receiver between the multipath signal carrier of receiving _1L(t)=cosw _1LT can only with a footpath collection of letters carrier wave S ₁(t)=S ₁Cosw ₁T keeps synchronously, and the phase difference θ between these two signals is 0, can realize coherent demodulation, but can cause introducing in the demodulation of collecting mail number in other two footpath their collection of letters carrier wave and C separately _1L(t) relevant restituted signal amplitude loss, change in polarity and the interference of phase difference θ.As other footpath collection of letters carrier wave S ₂(t)=S ₂Cosw ₂T and C _1LWhen (t) having phase difference θ, but the demodulated signal simple table is shown S ₂Cos θ, obviously phase difference θ will influence the polarity and the amplitude of demodulated signal.This phase difference loss can make the power utilization of multipath signal decline to a great extent, and cos θ can be defined as the coherent demodulation fissipation factor.The CLRAKE receiver will utilize training sequence or other channel estimation methods to estimate the polarity of cos θ, in order to avoid the polarity inversion of demodulated signal, but is unable to estimate the value of cos θ, therefore can not eliminate its influence.

Summary of the invention:

Technical problem: traditional rake receiver (CLRAKE) will cause the power utilization of multipath signal to decline to a great extent owing to there is the phase difference θ that can't accurately estimate between the carrier wave of different paths.At this defective, the utility model provides a kind of and realizes that on carrier wave multipath separates, and respectively multipath signal is realized the CDMA multipath synchronous demodulation diversity receiver of carrier coherent demodulating.Each the footpath signal reception all be coherent demodulation, three the footpath local carriers be 0 with corresponding three tunnel collection of letters carrier phase difference θ respectively, can not introduce the influence of coherent demodulation fissipation factor cos θ, the phase difference of having eliminated each footpath intercarrier has improved the power utilization when the cdma system downlink receiver is received multipath signal greatly to receiving Effect on Performance.

Technical scheme: a plurality of local coherent carrier that CDMA multipath synchronous demodulation diversity receiver utilization of the present utility model recovers realizes that with coherent demodulator multipath separates and coherent demodulation receives on carrier wave, avoided the CLRAKE receiver since each directly the number of collection of letters carrier wave have phase difference, can introduce the influence of coherent demodulation fissipation factor cos θ, cause the not good enough problem of receiver performance.Multipath signal carrier coherent demodulating Rake receiver comprises three the QAM coherent demodulator, the 2nd QAM coherent demodulator, the 3rd QAM coherent demodulators that are used for the three footpath collection of letters number separation and coherent reception, be used to adjust first delayer, second delayer of multidiameter delay, the first adder that is used for the three footpath signal stacks of I road, the second adder that is used for the three footpath signal stacks of Q road, be used for I road first multiplier of combined signal descrambling, be used for Q road second multiplier of combined signal descrambling; Comprise the input signal S that collects mail number in three footpaths _AD(t) send into a QAM coherent demodulator, the 2nd QAM coherent demodulator, the 3rd QAM coherent demodulator respectively, and the local coherent carrier cosw that utilizes three cover carrier recovery circuits to recover _1LT ,-sinw _1LT, cosw _2L(t) ,-sinw _2L(t), cosw _3L(t) and-sinw _3L(t) carry out coherent demodulation, the I that a described QAM coherent demodulator demodulates _T1, Q _T1The road signal connects the input of first delayer, the I that described the 2nd QAM coherent demodulator demodulates _T2, Q _T2The road signal connects the input of second delayer, first delay control signal connects the signal input end of described first delayer, second delay control signal connects the signal input end of described second delayer, the I of a described QAM coherent demodulator, the 2nd QAM coherent demodulator _T1, I _T22 road inputs that connect first adder through first delayer, second delayer respectively, the Q of a described QAM coherent demodulator, the 2nd QAM coherent demodulator are exported in the road _T1, Q _T22 road inputs that connect second adder through first delayer, second delayer respectively, the output I of described the 3rd QAM coherent demodulator are exported in the road _T3Connect another road input of described first adder, the output Q of described the 3rd QAM coherent demodulator _T3Connect another road input of described second adder, the output of described first adder connects descrambling code first multiplier, the output of described second adder connects descrambling code second multiplier, and the first local random sequence and the second local random sequence are imported the descrambling code that described first multiplier and second multiplier carry out I road, Q road combined signal respectively respectively.

Describedly be used to recover local coherent carrier cosw _1LT and-sinw _1LThe cover carrier recovery circuit of t comprises the first contrary modulation multiplier, the second contrary modulation multiplier, first narrow band filter circuit that is used to extract local coherent carrier, second narrow band filter circuit and first regulating circuit mutually that is used to adjust the first local random sequence and the second local random sequence phase place that is used for recovering from multipath signal the local coherent carrier of a certain footpath signal; Multipath pilot signal S _PilotConnect the input of first narrow band filter circuit and second narrow band filter circuit respectively through the first contrary modulation multiplier, the second contrary modulation multiplier, the output of described first narrow band filter circuit connects the described first contrary input of modulating multiplier through phase regulating circuit, and the output of described second narrow band filter circuit connects the input of the described second contrary modulation multiplier through phase regulating circuit.

Beneficial effect: the utility model recovers each directly local coherent carrier of the number of collection of letters earlier, can realize the separation of the footpath of three on the carrier wave then, and realize the coherent demodulation of collecting mail number in three footpaths respectively, the reception of each footpath signal can not introduced the influence of coherent demodulation fissipation factor cos θ, eliminate each footpath collections of letters carrier phase difference to receiving Effect on Performance, improved the power utilization of the descending multipath collection of letters number of cdma system greatly.And the utility model carries out descrambling after each footpath signal is merged again, simplified circuit.

Description of drawings

Fig. 1 is one a tunnel local coherent carrier restore circuit of CDMA multipath synchronous demodulation diversity receiver.Comprising the first contrary modulation multiplier M that is used for recovering the local coherent carrier of a certain footpath signal from multipath signal ₁₁, the second contrary modulation multiplier M ₁₂, be used to extract a NBPF of local coherent carrier ₁(narrow band filter) circuit 13 and the 2nd NBPF ₁Circuit 15 is used to adjust local scrambler PN _ILAnd PN _QLFirst phase regulating circuit 14 of phase place.

Fig. 2 is the schematic block circuit diagram of cdma system 3 footpath collection of letters coherent demodulation CDMA multipath synchronous demodulation diversity receivers.This equipment comprises three QAM first coherent demodulator 21, second coherent demodulator 22, the dried demodulators 23 of third phase that are used for the three footpath collection of letters number separation and coherent reception, be used to adjust first delayer 24, second delayer 25 of multidiameter delay, be used for the first adder M of I road three footpath signal stacks ₂₆, be used for the second adder M that Q road three footpath signals superpose ₂₇, be used for the I road first multiplier M of combined signal descrambling ₂₈, be used for the Q road second multiplier M of combined signal descrambling ₂₉

Embodiment

Fig. 1 provides the local coherent carrier restore circuit of the multipath theory diagram of the utility model CORAKE receiver.

This equipment comprises the first contrary modulation multiplier M that is used for recovering from multipath signal the local coherent carrier of a certain footpath signal ₁₁, the second contrary modulation multiplier M ₁₂, be used to extract first narrow band filter circuit 13 and second narrow band filter circuit 15 of local coherent carrier, be used to adjust the first local random sequence PN _ILWith the second local random sequence PN _QLFirst phase regulating circuit 14 of phase place; Multipath pilot signal S _PilotConnect the input of first narrow band filter circuit and second narrow band filter circuit respectively through the first contrary modulation multiplier, the second contrary modulation multiplier, the output of described first narrow band filter circuit connects the described first contrary input of modulating multiplier through phase regulating circuit, and the output of second narrow band filter circuit connects the input of the described second contrary modulation multiplier through phase regulating circuit.

The expression formula of a certain footpath down-bound pilot frequency signal (Pilot) is as follows among Fig. 1:

S _pilot＝PN _Icosw ₁t-PN _Qsinw ₁t (1)

PN wherein _I=± 1, PN _QExpression formula and PN _IIdentical, but PN _QAnd PN _IBe two different short PN sequences.Local two short PN sequence PN that produce _ILAnd PN _QLAfter adjusting, phase place gets PN _I1LAnd PN _Q1L, this two-way sequence and collection of letters S _PilotIn PN _IAnd PN _QSynchronously, by

S _pilot×PN _I1L＝cosw ₁t-PN _I1LPN _Q1sinw ₁t (2)

Receive a certain footpath signal carrier cosw as can be seen ₁T is resumed, through the first narrow band filter (NBPF ₁) can be used for the local coherent carrier cosw of a QAM coherent demodulator among Fig. 2 after the extraction _1LT.In like manner can obtain-sinw _1LT.

NBPF ₁Output can be used as PN _ILAnd PN _QLThe control signal of first phase regulating circuit (14) is worked as cosw _1LWhen the t signal is obtained amplitude peak, can think PN _I1LWith S _PilotIn PN _ISynchronously.Above-mentioned conclusion also can be used for PN _Q1LAnd PN _Q

Three footpath collection of letters carrier coherent demodulating receivers will re-use 2 and overlap the local coherent carrier restore circuit that is similar among Fig. 1, just change the phase regulating circuit output in the other 2 cover circuit into PN respectively _I2LAnd PN _Q2L, PN _I3LAnd PN _Q3LThis moment, the output of these two local coherent carrier restore circuits was respectively cosw _2L(t) ,-sinw _2L(t), cosw _3L(t) and-sinw _3L(t).

Fig. 2 provides the schematic block circuit diagram of 3 footpath collection of letters carrier coherent demodulating Rake receivers (CORAKE).This receiver comprises three the QAM coherent demodulator 21, the 2nd QAM coherent demodulator 22, the 3rd QAM coherent demodulators 23 that are used for the three footpath collection of letters number separation and coherent reception, be used to adjust first delayer 24, second delayer 25 of multidiameter delay, be used for the first adder M of I road three footpath signal stacks ₂₆, be used for the second adder M that Q road three footpath signals superpose ₂₇, be used for the I road first multiplier M of combined signal descrambling ₂₈, be used for the Q road second multiplier M of combined signal descrambling ₂₉Comprise the input signal S that collects mail number in three footpaths _AD(t) send into a QAM coherent demodulator, the 2nd QAM coherent demodulator, the 3rd QAM coherent demodulator respectively, and the local coherent carrier that utilizes three cover carrier recovery circuits to recover carries out coherent demodulation, the I that a described QAM coherent demodulator 21 demodulates _T1, Q _T1The road signal connects the input of first delayer 24, the I that described the 2nd QAM coherent demodulator 22 demodulates _T2, Q _T2The road signal connects the input of second delayer 25, the first delay control signal C _D1Connect the signal input end of described first delayer 24, the second delay control signal C _D2Connect the signal input end of described second delayer 25, the I of a described QAM coherent demodulator 21, the 2nd QAM coherent demodulator 22 _T1, I _T2Road output meets first adder M respectively through first delayer 24, second delayer 25 ₂₆2 road inputs, the Q of a described QAM coherent demodulator 21, the 2nd QAM coherent demodulator 22 _T1, Q _T2Road output meets second adder M respectively through first delayer 24, second delayer 25 ₂₇2 road inputs, the output I of described the 3rd QAM coherent demodulator 23 _T3Meet described first adder M ₂₆Another road input, the output Q of described the 3rd QAM coherent demodulator 23 _T3Meet described second adder M ₂₇Another road input, described first adder M ₂₆Output meet the descrambling code first multiplier M ₂₈, described second adder M ₂₇Output meet the descrambling code second multiplier M ₂₉, the first local random sequence PN _I3LWith the second local random sequence PN _Q3LImport the described first multiplier M respectively ₂₈With the second multiplier M ₂₉Carry out the descrambling code of I road, Q road combined signal respectively.

The local coherent carrier of among Fig. 26 tunnel respectively with three footpath collections of letters carrier waves with the frequency homophase, can provide according to Fig. 2:

I _t1＝I ₁+I ₂cosθ ₂+I ₃cosθ ₃+Q ₂sinθ ₂+Q ₃sinθ ₃(3)

Q _t1＝Q ₁+Q ₂cosθ ₂+Q ₃cosθ ₃-I ₂sinθ ₂-I ₃sinθ ₃(4)

I _t2＝I ₂+I ₁cosθ ₁+I ₃cosθ ₃+Q ₁sinθ ₁+Q ₃sinθ ₃(5)

Q _t2＝Q ₂+Q ₁cosθ ₁+Q ₃cosθ ₃-I ₁sinθ ₁-I ₃sinθ ₃(6)

I _t3＝I ₃+I ₁cosθ ₁+I ₂cosθ ₂+Q ₁sinθ ₁+Q ₂sinθ ₂(7)

Q _t3＝Q ₃+Q ₁cosθ ₁+Q ₂cosθ ₂-I ₁sinθ ₁-I ₂sinθ ₂(8)

I wherein ₁, I ₂And I ₃Being respectively three footpaths collects mail number through the output of demodulated I road signal, Q ₂And Q ₃Be respectively the phase difference of the 2nd and the 3rd footpath collection of letters carrier wave and the 1st footpath collection of letters intercarrier.

Because can be with the PN that obtains in the three footpath collection of letters coherent carrier restore circuits _I1L, PN _I2LAnd PN _I3LJudge I _T1And I _T2Therefore due time delay can finish the RAKE additive process before despreading, use PN thereafter again _I3LCarry out despreading.Can derive the RAKE receiving unit on Q road with similar method,, omit herein for avoiding repetition.

From formula (3)～(8) as can be seen, adopt 3 footpath collections of letters coherent demodulation RAKE receiver after, can realize 3 footpaths collect mail separation and coherent demodulation number on carrier wave, can avoid in traditional RAKE receiver owing to non-coherent demodulation fissipation factor cos θ ₂The mis-behave that causes etc. parameter.

Embodiment one

Present embodiment is to receive from three footpaths to recover local coherent carrier and PN sequence the pilot signal.The local coherent carrier restore circuit of Fig. 1 comprises the first contrary modulation multiplier M that is used for from the multipath collection of letters number local coherent carrier of a certain footpath of recovery signal ₁₁, the first contrary modulation multiplier M ₁₂, be used to extract a NBPF of local coherent carrier ₁(narrow band filter) circuit 13 and the 2nd NBPF ₁Circuit 15 is used to adjust the first local random sequence PN _ILWith the second local random sequence PN _QLFirst phase regulating circuit 14 of phase place.

Multipath is received pilot signal S _PilotMeet a NBPF respectively through the first contrary modulation multiplier and the second contrary modulation multiplier ₁Circuit and the 2nd NBPF ₁The input of circuit, a described NBPF ₁The output of circuit connects the input of described first multiplier, described the 2nd NBPF through first phase regulator ₁The output of circuit connects the input of described second multiplier through phase regulating circuit.The one NBPF ₁The output of circuit can be used as adjusts local scrambler PN _ILAnd PN _QLThe control signal of phase regulating circuit, as local coherent carrier cosw _1LWhen the t signal is obtained amplitude peak, can think PN _I1LWith S _PilotIn PN _ISynchronously, and this moment exalted carrier cosw _1LT and S _PilotIn certain the footpath signal the carrier wave homophase.

Embodiment two

Present embodiment is to carry out the carrier separation that multipath collects mail number and the CDMA multipath synchronous demodulation diversity receiver of coherent demodulation.3 footpath collection of letters carrier coherent demodulating RAKE receiver (CORAKE) circuit of Fig. 2 comprise three a QAM coherent demodulator 21, the 2nd QAM coherent demodulator 22, the 3rd QAM coherent demodulators 23 that are used for three footpath collection of letters carrier separation and coherent reception, be used to adjust first delayer 24, second delayer 25 of multidiameter delay, suppose the I road output signal I of the 3rd QAM coherent demodulator herein _T3With Q road output signal Q _T3The time delay maximum.The first adder M that is used for the three footpath signal stacks of I road ₂₆, be used for the second adder M that Q road three footpath signals superpose ₂₇, be used for the I road first multiplier M of combined signal descrambling ₂₈, be used for the Q road second multiplier M of combined signal descrambling ₂₉

Comprise the input signal S that multipath is collected mail number _AD(t) the local coherent carrier of sending into a QAM coherent demodulator, the 2nd QAM coherent demodulator, the 3rd QAM coherent demodulator respectively and utilizing three cover coherent carrier restore circuits to recover carries out multipath signal separation and coherent demodulation.The I that a described QAM coherent demodulator 21 demodulates _T1, Q _T1The road signal connects the input of first delayer 24, the I that described the 2nd QAM coherent demodulator 22 demodulates _T2, Q _T2The road signal connects the input of second delayer 25, the first delay control signal C _D1Connect the signal input end of described first delayer 24, the second delay control signal C _D2Connect the signal input end of described second delayer 25, the I of a described QAM coherent demodulator 21, the 2nd QAM coherent demodulator 22 _T1, I _T2Road output meets first adder M respectively through first delayer 24, second delayer 25 ₂₆2 road inputs, the Q of a described QAM coherent demodulator 21, the 2nd QAM coherent demodulator 22 _T1, Q _T2Road output meets second adder M respectively through first delayer 24, second delayer 25 ₂₇2 road inputs, the output I of described the 3rd QAM coherent demodulator 23 _T3Meet described first adder M ₂₆Another road input, the output Q of described the 3rd QAM coherent demodulator 23 _T3Meet described second adder M ₂₇Another road input, described first adder M ₂₆Output meet the descrambling code first multiplier M ₂₈, described second adder M ₂₇Output meet the descrambling code second multiplier M ₂₉, the first local random sequence PN _I3LWith the second local random sequence PN _Q3LImport the described first multiplier M respectively ₂₈With the second multiplier M ₂₉Carry out the descrambling code of I road, Q road combined signal respectively.Separation and carrier coherent demodulating RAKE that above process has been finished multipath signal receive.

Claims (2)

1. CDMA multipath synchronous demodulation diversity receiver, it is characterized in that: this receiver comprises three the QAM coherent demodulator (21), the 2nd QAM coherent demodulator (22), the 3rd QAM coherent demodulators (23) that are used for the three footpath collection of letters number separation and coherent reception, be used to adjust first delayer (24), second delayer (25) of multidiameter delay, be used for the first adder (M of I road three footpath signal stacks ₂₆), be used for the second adder (M that Q road three footpath signals superpose ₂₇), be used for the I road first multiplier (M of combined signal descrambling ₂₈), be used for the Q road second multiplier (M of combined signal descrambling ₂₉); Comprise the input signal S that collects mail number in three footpaths _AD(t) send into a QAM coherent demodulator, the 2nd QAM coherent demodulator, the 3rd QAM coherent demodulator respectively, and the local coherent carrier cos w that utilizes three cover carrier recovery circuits to recover _1LT ,-sin w _1LT, cos w _2L(t) ,-sin w _2L(t), cos w _3L(t) and-sin w _3L(t) carry out coherent demodulation, the I that a described QAM coherent demodulator (21) demodulates _T1, Q _T1The road signal connects the input of first delayer (24), the I that described the 2nd QAM coherent demodulator (22) demodulates _T2, Q _T2The road signal connects the input of second delayer (25), the first delay control signal (C _D1) connect the signal input end of described first delayer (24), the second delay control signal (C _D2) connect the signal input end of described second delayer (25), the I of a described QAM coherent demodulator (21), the 2nd QAM coherent demodulator (22) _T1, I _T2Road output meets first adder (M respectively through first delayer (24), second delayer (25) ₂₆) 2 road inputs, the Q of a described QAM coherent demodulator (21), the 2nd QAM coherent demodulator (22) _T1, Q _T2Road output meets second adder (M respectively through first delayer (24), second delayer (25) ₂₇) 2 road inputs, the output I of described the 3rd QAM coherent demodulator 23 _T3Meet described first adder (M ₂₆) another road input, the output Q of described the 3rd QAM coherent demodulator (23) _T3Meet described second adder (M ₂₇) another road input, described first adder (M ₂₆) output meet the descrambling code first multiplier (M ₂₈), described second adder (M ₂₇) output meet the descrambling code second multiplier (M ₂₉), the first local random sequence (PN _I3L) and the second local random sequence (PN _Q3L) import the described first multiplier (M respectively ₂₈) and the second multiplier (M ₂₉) carry out the descrambling code of I road, Q road combined signal respectively.

2. CDMA multipath synchronous demodulation diversity receiver as claimed in claim 1 is characterized in that the described local coherent carrier cos w that is used to recover _1LT and-sin w _1LThe cover carrier recovery circuit of t comprises the first contrary modulation multiplier (M that is used for recovering from multipath signal the local coherent carrier of a certain footpath signal ₁₁), the second contrary modulation multiplier (M ₁₂), be used to extract first narrow band filter circuit (13), second narrow band filter circuit (15) of local coherent carrier and be used to adjust local scrambler PN _ILAnd PN _QLFirst phase regulating circuit (14) of phase place; Multipath pilot signal S _PilotThrough the first contrary modulation multiplier (M ₁₁), the second contrary modulation multiplier (M ₁₂) connecing the input of first narrow band filter circuit (13) and second narrow band filter circuit (15) respectively, the output of described first narrow band filter circuit (13) meets the described first contrary modulation multiplier (M through first phase regulating circuit (14) ₁₁) input, the output of described second narrow band filter circuit (15) meets the described second contrary modulation multiplier (M through first phase regulating circuit (14) ₁₂) input.

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