TWI230521B - Improved pseudonoise code tracking loop using DS/SS in the random variables correlated multipath fading channel - Google Patents

Abstract

An improved digital pseudonoise code tracking loop for DS/SS is disclosed. By the inherent diversity, the improved digital pseudonoise code tracking loop is able to be lodged in Rake receiver to avoid the unstable locked points of the error signals. In conventional code tracking loops, unstable locked points usually occur, and the error signal is randomly aberrant for multipath fading. Therefore, the elapsing fading channel must have a sound guiding function, and its multi spreading path must be also randomly correlated. Moreover, this invention discloses an effective way to regenerate and eliminate multipath interference to improve the error characteristics of this technique. The equations of the error characteristics and the error signal are analyzed with repeated computer simulations. Furthermore, the simulation of the timing jitter and the mean time to lose lock is also disclosed. This invention much improves the technique in the related area disclosed.

Description

1230521 IX. Description of the invention: Synchronize the locally generated de-spreading sequence with the pseudo-noise (PN) sequence carried by the incoming signal. It is one of the most important functions of a direct sequence spread spectrum communication system (DS / SS) receiver. The income signal 'Cao Jing' carries the information symbol (inf〇rmati〇n_ | 3earingSyml3〇ls). Modulation, and parent-to-heteroporous interference (noise) and channel impairments. Only when synchronization is achieved ’can the benefits of the direct-sequence spread-spectrum communication system be known, such as interference rejection, anti_jam performance, and better spectral utilization. This kind of synchronization usually requires two stages to achieve: the first is the acquisition stage, which can make a rough alignment of the income sequence and the locally generated sequence; the second is the tracking stage (the Into the stage), mainly to ensure that this calibration can continue to be maintained throughout the entire message detection process (detection processes). Furthermore, a good code tracking loop can effectively reduce the severity of various problems caused by timing errors, and thus improve the performance of message detection. For the issue tracking of spread spectrum communication technology, most of the analysis is related to analog implementation (such as &amp; 1§ implementation) and additive white Gaussian noise (addkive whke awqn w channel research content. But 'except In addition to the additive white Gaussian noise, the tracking ability of frequency-selectivefad ^ (conventional code awful king Ws). Based on the extended Carmen waver ), The impact of multiple paths (whether she was codedday for the joint evaluation of the evaluator (j〇imestimat)), will be able to further effectively deal with multiple paths, but because the DS / SS wireless rail system is in the interference Operating under very severe conditions, we will find that in the real society, the presence of the Carmen Yiqi (Qing) or recursive least squares (RLS) algorithm does not have any functional advantage, even if it is used Larger calculations (heaviercomputati〇nall〇ads) (ie, and higher processmgmtes) (ie. Twice the chip speed is the same. In fact, (n umber of resolvable channel paths) can completely change the function of the extended Carmen filter. In addition, some people have proposed a new code tracking scale and reduce the rural heavy duty system reform M technology, but these two The ribs are still based on analogy-implemented technologies. 'So they are not only implemented in cans, they also cannot adjust the tap spacing of centrifugal receivers to improve the performance of diverse operations. In addition, no one has Proof the error signals (esignals) and county characteristics (err0r characteristics) to verify the attractive (pca function). On the other hand, in order to reduce the cost and the complexity of the user terminal of the spread spectrum system (SS), The multiple-access terminals in the frequency domain (frequenCy- (jivisi〇n) or time-division) that can be transmitted and charged are comparable to each other, and the full-digitization of the modem is undoubtedly urgent. Desirable and needed. In the present invention, 'an all-digital, non-homogeneous (n0n_c〇herent) improved code tracking circuit month b is sufficient to select the limited bandwidth of the channel (bancji) imite (j) operates on DS / SS systems. In the technology described, the present invention uses the assistance of central_branch c〇rreiati〇n to embed an improved code tracking loop into a rake receiver. (RAKE receiver). Utilizing the characteristics of the correlation of the central section, the error characteristics obtained on the RAKEfmger of each rake receiver can be maintained at a chip duration; as a result, encountered in previous research The problem of self-interference can be effectively reduced. By exploiting the maximum ratio combining (MRC) and multipath interference cancellation (MPIC) to develop intrinsic diversity, the technique proposed by the present invention can avoid the error signal locking point (Locked points), which improves the characteristics of the error. Using the error signals obtained by the proposed technology, it is confirmed that the multi-path 1230521 fading channel is dark in any variable. "Slaves are a stubborn observatory (-_). Furthermore, the excellent improvement obtained by the technology proposed by the present invention can be confirmed by the system of the present invention in terms of timing (average time) and loss of lock average time (ueantimetGlGsek) ek (MTLL). The diagram briefly illustrates the improved code tracking circuits proposed by Figure- (A) and Figure-⑻; Figure 2 S ^), S2 (s), and S3 (〇 graphics; Figure 3⑷ raking fingers in the front (卿 eding fin㈣_ (Residual mutual) (rcs_ c draw correlation); (b) ^^ (given flnger) (desired err〇r characteristic); M ^ m) (succeeding finger); Figure 2 (continued) (d) The error we want Characteristics and residual cross-correlation; Figure 3 (continued) (e) Effective error characteristics; Figure 4 Characteristics of pseudo-noise code chasing after the road Short-term average of the error of the chasing loop (MCTL) error; Figure 6: Short-term average of the error signal of the multi-sexing _ except for the improvement of the improved handle light and light-weight; 1230521 Figure 7 of the early-delay (EL) error signal Short-time average; Figure 8. Short-time average of early-delay (EL / MPIC) error signal under multipath interference cancellation; Figure 9: H = 32 and π 64 obtained using the proposed technique Simulation results of mean-squared timing errors; Figure X. Under the conditions of == 16 and <= 32, the user would like to mention Simulation results of mean time to lose lock obtained by the technology. Detailed description of the preferred specific examples 1 · Channel Model Many studies have used different channel models and multiple analysis techniques to complete the Of receiver diversity combining. Some studies use discrete-time multi-path channel models, where each multi-path element is assumed to be wider than the chip dumtion, Therefore, the signal received by each transceiver (tap) is individually independent. Some studies use a tapped-delay-line (TDL) model, which is based on the assumption that the bandwidth of the transmitted signal is 'ratio code' The chip rate is narrow or equivalent. In addition, some studies use a continuous-time multipath channel model (conti_us_timemultipathchannelm0del) to evaluate the correlation between the signals received by different fingers of a dry receiver to evaluate The performance of a consumable receiver. For frequency-selective fading channels (freqUenCy_selective color output% channel) For transmitted broadband signals, the signature duration is usually shorter than the channel coherence time. Therefore, the channel changes quite slowly, and its characteristics can be accurately measured. Therefore, the bandwidth of each signature waveform is wider than the channel coherence bandwidth 1230521, and the frequency-selective fading channel is most often represented by TDL, where the transceiver interval is i / 仏, Transceiver weight coefficients (tap weight coefficients) are given as zero-mean complex-valued stationary Gaussian random processes. The number of resolvable paths per user is usually estimated as [_ΑΛ ″ +1, where 4 is the channel multipath spread, and Lx ″ is the largest integer, and this largest integer is less than or equal to X. Using this model, the equivalent low-pass time-varying impulse response (equal 1〇w_pass time-varying impulse response) of wide-sense stationary channel and uncorrelated scattering can be expressed by the following formula : / = 0 where the six offices /) represent the delay time 1 and the impulse response at the immediate time (line 111 € 丨 1 ^ 111: &gt;, called (/), indicating the time after: the sending and receiving of complex values are weights and Rayleigh Distributed magnitudes and uniformly distributed phases, and the number of decomposable paths is (z + i). 2 · System description A bandlimited DS / SS system with limited frequency I, its modulator (modulator) ) And the demodulator (demodulator) diagram have been thoroughly studied. In order to explain in detail the operation details of the improved code tracking loop proposed here, Figure 1 is a complete illustration of it. Chip-matched adapter (ehip-matched fiiter) The output fundamental frequency signal and the square root raised cosine (raise (jc〇sine) conversion function (complex representation of transfer V% (/) is / = 0 W = —00 'g [t-mTc + lTc] + n (t) (1) 123 0521 where W} m and | m | N are quotient integers (that is, the integer part of m / M), and the absolute value of m is #; from is the signal processing gain; tV is the iW code length; rc is the chip spacing ; 0⑺ indicates phase error caused by front-end non-coherent down-conversion process, and the result is incorporated into αι (〇; d_; information-bearing) Quaternary phase-shift keying (QPSK) complex symbol; ck is the a chip value of the / W sequence (PN sequence); g⑺ is the overall chip shape ) Fourier transform; and the power spectral density of the noise component (ρ〇λ · 叩 沉 ㈣ density) n (t) is SN (frN〇GN (f) / P. At t The signal of the corpse (k + s〇Tc and 4 __ = (1 ^ 々- (1/2) ding (: (that is, the sampling rate of 2 / Tc)) is represented by r (〇, where 'is the A: a normalized code Chip timing error (normaiizedchiptimingenw) to generate two parallel sequences: an integer-instant stream and a semi-integer instant stream (Half-integer-instant stream) rMl / ”= (A: + q-(1/2)) Γ Α · Multipath Interference Regeneration First, the integer real-time example r々 is input into the multipath of the central section Interference regenerators (central-bmnch multipath interference regenerator, CB-MPIR), they must buffer the η time point before entering the central section correlators, in order to wait for the low-pass filtering of the integral dump in the multipath interference regenerator (I / D latency) required for I / D work (I / D latency; at the same time, a semi-integer real-time stream rr (i / 2) is input to the multipath interference regenerator of the front section (eariy branch multipath interference regenerator (EB-MPIR) and multi-path interference regenerator (late-bmnch legs and interference re-genemtor (LB-MPIR)) in the rear section. They must also buffer the η time point before inputting the front and back segment correlators, in order to wait for the multipath interference regenerator to pour out the low-pass filter 1230521 wave filter (I / D) to work — in the path , Each _ c 'extends η a—. In CB_MPIR h is the first de-spreading at L + 1 C | _. By multiplying the output value of the I / D filter by the delayed de-spreading sequence e ^ | Mv, the pieces can be passed to each path. Signal. Therefore, the cross-correlation of the fingers of the generalized architecture can be expressed as follows: 2 ik /-ID L xc I \ (k'p cI ^ Lv / (2) where 1D {·} represents the I / D verification operation (ie id (.} = (1 / n) Σ „: 1 {}) A similar operation branch is also found in EB_Mp North LL, # LB-MHR ^ 仏 ⑽. It is generated by the p-half integer ㈣ stream of the rake receiver The cross correlation can be expressed as follows: Η \! 2) -ρ

(3) and ymn ID ^ HV2hp

(4) Please note ’! / D delay is an important design parameter. It means that the same adjustment and spacing used in I / D operations is recommended, as it is as small as a bowl, so it must be short, to avoid the possibility of data sign inversion (data signinversion). In other words, the milk filters of eb_MPIR, LB-MPIII and CB-MPIR must have a wide enough bandwidth to accommodate the results of data modulation. However, the distance between adjustments must also be long enough to correctly estimate the effect of the channel, reject unwanted noise, and effectively reconstruct / eliminate multipath interference. Since I / D overrun operation uses "quote as chip durations" to perform multipath interference reconstruction, the front segment, rear segment, and center segment are related to each other. D is delayed but delayed, and multipath interference is eliminated at the correct phase. In this way, before the cross-correlation is achieved, the improved code tracking (S-Curve) under the forward signal (MCTL / MPIC) error signal and 8-shaped B · multipath interference cancellation is in the 刖 £ section and the back zone. In the correlator of the segment and the central segment, the sequence corresponding to the adjacent path is the first to stream from the delayed integer instant and the delayed semi-integer instant stream before the correlation with the local pseudo-noise sequence (ie, "}" And {. (1/2) — „}). Therefore, the mutual correlation of the correlators of the 'front section, the rear section, and the central section, that is, pair, V. The sum can be expressed as follows: 1M, and VE, k (1/2) -p

λ 1 Λρ + 1 \ y E, (k ~ n) n ^ y E, (k-n) n XC \ k-n \ N

Kk

yL, {kn} n yL, {k ~ n} n <Vh'v where ® represents the convolution operator is the impulse response function of the first-order low-pass filter, and its conversion function is // (ZΚΙ -θ / Ο-όZ1), & (一 1¾¾, has a bandwidth Bb comparable to the symbol rate 1 / T. The data modulation result and channel fading result are &lt; It is multiplied by &quot; f's complex conjugate to compensate. In addition, it can effectively maintain the error characteristics of each finger in the range [-7; 7;] to reduce the effect of self-interference 12 1230521. Therefore, the error signal caused by the technology proposed in the present invention, that is, the improved code under multipath interference cancellation, such as the slave loop (MCTL / MPIC), can be obtained by using the maximum combining ratio (MRC) standard. Obtained, its expression is as follows: where (·) * indicates that conjugate complex numbers are used for operation. After several operations (manipulations) (as described in the appendix), the error message of MCTL / MPIC says that ε production ε can be rewritten As follows: ^ MCTL / MPIC. First, /,

Ck-(5Γ0 -8Γ, + 4Γ2 ~ Γ3) .51 ^) + (3γ〇 + 5Γ2 -3Γ3 + T4) S2 (s) + (5Γ0 ~ 8Γι + 4γ 广 οχ »外 χ) = outer 7;) { A violent statement] L 士 Κ]} s2 (^) = g [{^ ~ l) r] g [(£ + i) r]-g [(e + \) TC] § [(ε-\) TC ] (^) = gfc + i) r] g [^ € + j ^ _ xyc] g [(^ ^ l) tc] Γ〇-ΣΙΚ 13 I23〇52i Γ2 = ERek

Γ3 = ZRek

And Γ4 = ERekv4}.疋 ’r. , Γι, Γ2, Γ3, Γ4, etc. will change with the change of channel action, although there is no _ 明 _ symbol A or, to indicate. If m is the independent complex height of the mean difference scale = machine variable UandGmvariables), then the _ness (that is, the sonar curve) can be further expressed from the formula as follows: s IC = (£ ίΓ〇}) [55, 1 W + 3S21) + 553 (ε)] (8), Chinese <.>, And E {·} represent the time average (time.average) and · operand (which can be operated). Regardless of the way the channel transceiver weights ~ are combined (for example, in multiple paths, it is irrelevant, lateral, or arbitrary with time-varying relevance), McTL / MpiC error signs and S-turns Under the general prison point, all horses must have a symmetrical symmetry, because the secret), the secret), and the heart have this attribute. ⑽), Secret), and the shape of the heart palates please see Figure 2. The error signal and S-curve of the modified code tracking circuit (MCTL) 14 1230521 The error structure of the modified code tracking circuit (hereinafter _MCTL) is similar to that without #path interference cancellation, and its formula can be re-expressed as follows:

4 gas such as Σ ί-ρ \ Uk ^ / Λ -p a /)) '’E, k-VLk V J = (Γ〇 (9) + (r〇 where

-P -P UE, k ~ P ULJc = ΓΗ ^ 2) ~ ρ-η XC | ^ K / ^} ® kk. (L〇) If the average weight of the transmitter is zero and independent of each other, then _ The curve formula is as follows: s L ('<• pick G) + s3 (4 (11) Also under any return conditions, the MCTL error signal and the s curve are also oddly symmetric at the same lock point ε = 0. When Tian Kmao's 25 weightings are zero-mean and independent, the error signal of each finger will still be affected by the neighboring lion and cause self-interference. For a specific propagation path, some typical finger error signals will Pick her red __, # exhaustively delete it. And the residual mutual 15 1230521 correlation (beyond the half chip spacing) will inevitably be detected and cause some unwanted error characteristics (ie self-interference), in Residual cross-correlations on the front and rear fingers are shown individually in Figures III and (c). As for the difference in characteristics and self-interference, they are individually shown in solid and dashed lines in Figure III. Self-interference Naturally, it will hinder the desired error characteristics. The effective error characteristics of MCTL using MRC from individual propagation paths are shown in Figure 3 (e). As a result, the proposed Using the residual error characteristics of MTL's MCTL, its position will be above the effective error characteristics produced by all the fingers. At the same time, any specific finger can support the shipbuilding capability through the correlation of the central section. From the corresponding broadcast path and the adjacent propagation path side to the code error fiber. For this reason, when the lake is a _Mpic technology, only the multipath interference from the adjacent path needs to be dealt with. D. Comparison is for easy comparison, The present invention also proposes an error signal for the rake code tracking circuit. Each rake finger has a signal as follows: ^ ELIMPJC —: Σ | Vp (12) 4L: = ς I Vp Κ4 -Κ4} (13) Multipath interference cancellation (MPIC) and circuits without MPIC. It shows that the error signal caused by multipath interference may be biased due to the residual cross-correlation of adjacent paths, thus causing the lock &amp; point to move. In the appendix This is explained in more detail. 3. Data Result 16 l23〇52i After the above statistical analysis and Monte Carlo simulation on a computer, the values obtained are shown in this section. Set The pseudo-parameters are as follows: Frequency PN code chip shape chip rate chip rate signal rate of modulation system operator QPSK; 900 MHz; m-sequence with generating polynomial g (x) = l + x3 + x7 square-root raised cosine with a rolloff factor a = 0.22; 7 / rc = 1.27Mchips / s;

1 / T ^ \ 0K symbols / s; 32 samples; the power of the three propagation paths of the channel is equal, and the relative delay between the eight subsequent multipath elements, using an independent jakes channel fading model, the maximum fading rate It is 83.3 Hz; therefore, each transceiver weight has the intensity of the Rayleigh distribution and the phase of the uniform distribution. In this model, five fingers are used to avoid possible energy loss, where the segment filter bandwidth is equal to 1 = 1. / 7; The normalized bandwidth is normalized = 10-35 &gt; &lt; 10-351〇-4 and 5 &gt; &lt;10-4; ^ 16, 32, and 64; 50 000 QPSK data signals. Figure 4 shows the S-curve of the code tracking circuit used for comparison. Dotted and dotted lines represent MCTL and

MCTL / MI> IC theoretical S-curve, MCTL, MCTL / MPIC, EL and EL / MPIC simulation results are also plotted. Obviously, the simulation results are very close to those obtained from the previous statistical analysis. Furthermore, MCTL / MPIC has a more robust introduction capability than other models, while MCTL's S curve is still higher than EL or EL / MPIC. The S curve of EL is not meaningful, so EL and EL / MPIC will actually suffer from severe multipath interference. It can be clearly seen from Fig. 4 that by using the technology proposed by the present invention, the problem of S-curve deviation caused by frequency selective fading can be reduced. In order to further verify the ability of the comparison technology to be introduced on a time-varying multipath channel, the present invention simulates the short time averages of many MCTL, MCTL / MPIC, EL, and EL / MPIC error signals, as shown in Figure 17 and 1230521. It can be clearly seen in the figure that the error signal of the mctl spear is always oddly symmetric, and the lock level is unchanged, so it can confirm its attractive ability. However, the lock point that sees # EL / MPIC 々 差 5 will change due to the influence of _ Wei Dao, because the discriminator is connected to the road and the moon can generate multi-path interference. In Mctl and mctl / mpic towels, the central section correlator can financially limit the residual mutuality of fine and fine, so more stable signals can be obtained, as shown in Figures 5 and 6. . Because the present invention detects the signal received by each path individually, in the traditional delay-locked loop (DLL), the upper position of the individual error signal generates self-interference, so in turn_4 make 4 codes # Residual errors of the pitch towel produce deviations. The adopted channel is the worst case scenario, because in this case, each path may move the lock point from one thief to another. From the above readable multiple clutters lead to a large time series, while it is not necessary to simulate the traditional delay-locked loop and the chaotic momentum of the previously mentioned technology on the theoretical multi-path channel (# ㈣ 和 _mean time (MTLL) is not necessary Because they have been proven to be very susceptible to the I response of multipath channels. In order to δ evaluate the steady-state performance of the technology proposed by the present invention (), the normalized loop bandwidth is defined as follows: (14) The sensitivity and slope of the loop error characteristic of a non-numerically controlled vibrator (niimericaiiy contr〇ned 〇sciUat〇r), for MCTL / MPIC, can be expressed as follows: Heart <五 {Γ〇}> · 5πα sin (^) (l -a2) +2 cos (^) (l-3α2)

4cos (; ra) cos (f) T (l-a ^ Jl-4 ^] For MCTL, it can be expressed as: 18 1230521

2cos (; ra) cos (yo) is difficult to call 〇}〉 · Under different signal-to-signal ratios (Signal_t_isemtiG, SNR), the MCTL / MHC and MCTL mean square timing errors of the Reynolds BA can not be reduced. Computer simulation shows, as shown in Figure 9. It can also be seen from Figure 9 that the mean square timing error of MCTL / MHC is much longer than the mean square timing error of MCTL. This means that under the same normalized loop bandwidth, MCTL / MPIC has more stable performance in timing jitter. The out-of-lock average (MTLL) is not important to the code and circuit, and _ is under the condition of low inspection. In the traditional secret loop circuit (DLL), the MTLL surface Wei circuit maintains the synchronization average time; similarly, in the improved code tracking circuit provided by the present invention, Yujiang indicates that all the power consumption Refers to the average time to maintain synchronization. In other words, Caijiang is also the average time between two consecutive moments when the finger is out of lock. Under different SNR conditions, the MTLL simulation results of the improved code tracking loop with and without Mpic are shown in Figure 10. As can be seen in the figure, the MTLL of MCTL / MPIC is always longer than the Mπχ of MCTL. Because the area of the S-curve of mctl and total c is larger under positive e ', it means the state of escape energy of Bixian Nuclear University is determined, so the average time to lose scale is also long. 4. Conclusion The present invention provides a new and improved pick-and-trace circuit, a cross-spectrum spread spectrum communication system, and frequency-selective fading channel communication. Utilizing the essential diversity and multipath interference cancellation methods, the technology proposed by the present invention will provide better introduction capabilities. After obtaining the analysis results of the $ S scale, they are compared using a computer simulation. In addition, in order to taste green, the present invention also proposes a large-scale error signal, time tremor, and loss of lock. · The riding technology proposed by the present invention can be improved by 19 1230521, and this point is clearly confirmed.

20 1230521 Appendix Derivation of Error Signals In order to derive the error signals and s-curves of the proposed technology in more detail, the present invention will propose more equations below. In the formula of Article ，, the correlation produced by the instantaneous integer stream of the root finger of the rake structure can be rewritten as follows:

{k} n = ID {rk ^ p χ ^ | ^} where A &quot; nk = ID {nk_pxclklN} and δ M, k 1Ό] ΣαΙΣ-s [(k ^^-P ^ l + sk) τ]]

For unimportant residual cross-correlation. Here, the equation is broadened to the equation, because the channel usually changes slowly, so it can be considered to be constant over several times. «~ ⑺ omitted in Jane

, ΚΡ ~ P Similarly, and can be rewritten in more detail as: 21 (18) 1230521 Ί η ^ _2 LV Δ J Tc

yE. {k} n = ^ K- (l / 2) -p X Clp ^ {k} MS + ^ p + ^ {kl} Aig [ί 〇 ^ + 9 Lv L) Tc λΡ λΡ + TlE, k + SE , k and yL \ k} n = ^ \ [k- {M2) -p XC |) tl | iV K ap ^ {k ~ \} MS + V〆㈣ Λ 户 AP 4- yiL, k + S i, k

Tc (19) where 8k + l ~ P ~~ Tc / = 0 m ^ k sE, k = iD \ ^ d (k) xlg [l ^ pyp + \

Lj

'Σ C \ m \ NC \ k \ N * S k—tn + l — p ~ \ ~ Sk— Tc 2)

Sl ^ = IL Σ a / 4-i) Mg £ k + l-p +-Tc, 丄)

Σα1 Σ ά {η ^ η \ ΑΗ ^ 8 ik-m + lP + Sk ~) Tc I Λ 1 = 0 m ^ k- \ Lv LJ JJ Furthermore, in the first center section, the front section, and the rear section The cross-correlation of sections, that is, v ^, and vL, can also be rewritten in more detail as: 22 1230521

Upk = \ rk_p_n + z p +】 {k—n} n) XC \ k- x c Female—4 '

} ®K = (ap ~ ap- \ ^ ap + \) d {kn} MS [£ k-nTA + (^ 1 ~ QP -aP + 2) d {^ n} hiS {^ kn + (ap- \ ~ ^ p-2 ~ ap ί} Λ / gm] + ni, p- ^ two p + i ni -¾ ^

UE, k = \ k ~ (\ / 2) -pn ~ (yPE, {kn} n ^, (kn) „) XC \ kn \ N JX C \ k ~ n \ N} ® K ^ (ap ~ aP + \ ap-\) ^ (kn) M ~~) ΤΛ + (βρ + 1 ~ ^ p + 2 -ap) d (kn) Mg {(^ kn + ^) ^ c] + ^ E, k-^ E , k ~ + ^ E, k ~ ^ E, k ~ ^ Ej!

UL, k = | ^-(l / 2)-^-«~ (Κ ^ -η) η + yPL, (k ~ n) n) XC \ kA ~ n \ N JX C \ k ~ \ ~ n \ N) ® K = (^-Vl -ap-l) d (k ^ -n) NS {^ kn ^ ΤΛ

^ (ap_) -ap ~ ap_2) d (k_ ^ n) Mg {(sk_n ~~) ^] + 仏 — 私 -1-七 1 + yttrium-fe1-% + 1 where npK ^ (nk_n_pxc ^) ®hk Κ-] = ηΓ-! ^ Κ ((η [Mm® Sound kp 23 1230521 nEX ~ (nk-(\ / 2) -np XC \ kn \ N) ® ^ ^ -n ^ _n®hk ((filk

Kk = (^-(1/2)-,-^ X v) Θ K

Kkl-KL®Ki {Kk

K :: = KL®K {{n [, = (ΈαιΈάι ^ Λ \ Λ ^ x8 {{kp + i + £ kK ~ \) ®κ 1 = 0 m ^ k

^ lk = (TjaiYjd (rn) MC \ k \ NC \ m \ N ^ ^ m ~ P + 1 + Sk ~ ~) TΛ) ® K

/ = 0 m ^ k L Σ d {m} AIc \ k ~] \ / \ m \ MxS [(k-m-p + l + ek-) Tc]) ®hk

1 = 0 m ^ k- ~ \ Z k ~ i = k; in®Km, k ^ -k: in®KWuk

Sacrifice: Sacrifice L®h to bully kX, handle ~ heart two k: \ ®h bully, and further, rewrite the definitions of T〇, TuT2, T3, and T4 as:

-ΣΚ.ΙΙ

Vp Γι = Έκ ^ αΡαΙ ^ = XRe ^^ Vi)

Vp \ fp 24 1230521 = ZRe ^ Vi) = J] RQ {apap ^} V /? Vp =! &Gt;{Via; 2} = ERe (a;}, it = state a; +2} = ZRe {a &gt;} Listen to it r2 = | ~; +2} = 浐 KV2} = ZReKv2) V / 7 = ZReK -1 &lt; +1} = Υ ^ {αρΛαρ ^ 5 (21)

p Vp r3 = ZReKv3} = J] Re {apap + 3} p Vp = | &gt; «2}: 5 &gt;{a; _lV2} p Vp = ZRCazhou V2} = ZRe {'V2} p V /? And r4 = | &gt;{V2a; +2} = 5 &gt; K—2 ~} P Vp

Here, the noise variable can be set to zero to focus on the derivation of the correlation (and cross-correlation) between the signals, which will produce error characteristics and indeed contribute to the ability to introduce the code tracking loop. In fact, the addition of the f, Bai Tongsi miscellaneous flood channel (than the fact, the Cause (J by AWGN) and reproductive deafness (—M) caused by the inclination, after the expected value calculation and the daily average f calculation will be Disappearance According to the noise, regenerative and noise terms (nGiset_s) _ recording, the misplacement is the only white quantity. As mentioned above, the error signal under MCTL / MPIC can be heard by some algebra. 7). 25 1230521 In addition, for MCTL,%,% &amp;, and ^ ^ can be rewritten as: ΰ [= {rk_p—, C \ k_n \) ®hk + ap-ldik-n) M 8i (£ kn-W〇) + +? ^ = (V (l / 2)-^ X V-Lv) 0 ^ = ap ^ {k ~ n} MSK ^ k ^ n ~-) Tc] ^ ap ^ { k ~ n} MS [^ k ~ n + ¾ + ^ E, k

VL, k = irk-(\ / 2) -pn XC \ k-\-n \ N) ®K = ^ pd (kln) MSi ^ k ~ n + 2 ^ Tc ^ + ap-^ {k-^- n} MS [^ kn + ^ L, k + ^ L, k (22) In the formulas of (20) and (22), the second term of &lt; 々, and will undoubtedly cause self-interference, thus making EL The lock point of the EL / MPIC error signal produces a time-varying shift. 26

Claims (1)

1230521 10. Scope of patent application: • An improved pseudo-noise code tracking circuit suitable for direct sequence spread spectrum communication system in arbitrarily variable correlated multi-path fading channels. The chip is adapted to filters, samplers, and centers. Multi-channel interference regeneration of the segment, multi-path interference regeneration of the front segment, multi-path interference reproduction of the rear segment, middle segment correlator, front segment correlator, rear segment correlator, maximum combination The ratio is composed, with the help of the central sector correlator, an improved code tracking circuit is embedded in the rake receiver. The characteristics of the sector correlator are used, and the error characteristics obtained by the fingers of each handle receiver are It can maintain a chip interval; this will effectively reduce the problem of self-interference; and by using the maximum combination ratio and multiple interference cancellation to achieve the essential rural-like combination. 2. An improved pseudo-noise code tracking circuit suitable for a direct-sequence spread-spectrum communication system in an arbitrary variable-related multipath fading channel as described in item 丨 of the scope of patent application, in which a chip is adapted to a filter, It is to effectively limit the bandwidth of the received signal and arrange the waveform, and can achieve the Nyquist-type inter-symbol interference characteristics and reduce out-of-band noise and interference. Among them, the chip is adapted to the baseband signal output by the filter. The complex expression of the square root raised cosine conversion function is: / = 〇W2 = -o〇 ^ g [t-mTc ^ lTc] + n {t) where} M and | m | N are integers of quotient (ie w / M integer part), w absolute value #; M is the signal spreading processing gain; # is the length of the pseudo-noise code; reduced to chip spacing; 0⑺ represents the phase error caused by the non-homogeneous frequency reduction processing at the front end, and the result Incorporated into α 丨 ⑺; (1 state is the complex symbol that is keyed by the quaternary phase shift from {所} to carry information; ck is the first chip value of the household # sequence (pNsequence); g⑺ is the overall chip shape Fourier transform G⑺ = rcG⑹; and the power of the noise element 27 1230521 spectral density 呦 is ⑽GW P; at ㈣ + ε and t + + Η Η 1 / ^ Λ is expressed as r 其中, where &amp; is the (normalized chip timing error) to generate two flat 仃 sequences: an integer real-time stream fc = r (U)} and a semi-integer real-time stream k-⑽ =... As described in the first patent claim range-a kind of direct-sequence spread spectrum communication system suitable for arbitrary variable-related multi-path fading channels Improved pseudo-noise code chase loop, in which the center section of the heavy yttrium path interference regenerator and interference canceller, the front section multiple path interference regenerator and interference canceller, the rear section multiple path interference regeneration The device and the interference canceller are parallel signal sequences. After the H-terminal of the multipath receiver is accurately reproduced, the interference can be eliminated before the receiving tank enters the correlator of the corresponding section. Among them, the center section's multiple The path interference regenerator is to receive the signal 4 input from the integer instantaneous sampling point and send it to the next mid-range side device. Due to the integration / tilt-out filter and wave filter magnification factors, a buffer is required. To delay the output; at the same time, half-integer sampling point 4 The multipath interference regenerator in the front section and the multipath interference regenerator in the rear section are also due to the delay factor of the integration / tilt filter. Before entering the front and rear section correlators, they must be Delay; in the multi-path interference regenerator of the central section, for each of the (L + i) paths, ~ is first used to despread the frequency, and then the signal of the wheel on each path can be regenerated , By multiplying the round-out of the integration / tilt-out filter and the delayed spreading sequence Q B7; in this way, the intersection and co-correlation of the integer sampling information string of the second line on the rake receiver can be expressed It is: z {k} nY ^ ID [k_pXc ^ Among them, ID {.} Represents the action of integrating / tilting out the filter, 28 1230521 / State = ΜΣ; = {.} The same operation can also be applied in the front area The multi-path interference regenerator of the segment and the multi-path interference regenerator of the rear segment of the multi-path interference regenerator can be expressed as: aP / Hm1 / 2) -pX% When | v} and λP, the product of Vi | AJ should be divided into the design record of Yanlang Prostitute— Jian Yao; The continuous integration range operated, in order to avoid the effect of data sign inversion, it must be kept smaller than the program refinement, that is, the integration on the multi-path interference regenerator of the front section, the rear section and the center section The / out filter must have a sufficient bandwidth to accommodate the effects of data modulation. 4. An improved pseudo-noise code tracking circuit suitable for the direct sequence spread spectrum communication system in an arbitrary variable correlation multi-path fading channel as described in item 1 of the scope of the patent application, wherein the central section correlator, the front Segment correlators and post-segment correlators use parallel signal sequences to extract one-to-one correlation characteristics and implied timing characteristics of pseudo-noise signals transmitted by each distinguishable multiple propagation path. In the front-end, rear-end, and middle-end segment correlators, the related multipath interference from adjacent road shuttles is first instantaneously sampled and delayed with a delayed integer before it is cross-correlated with the virtual noise sequence at the local end. The integer instantaneous sampling information string performs a subtraction operation, so 'the cross-correlation on the correlators of the front, back, and middle segments of the P segment, that is: 29 1230521 «pnd' can be expressed as: ^ kpn%, 1 ㈣㈣ Zik-n} ^ Z {k ~ n) n XC, IM'vxc ®hki vik, C | person-called Λ, (V «! V and rk_ (m, -p- η '·, wide 1 Λ shot 1 Ν y L, (k-n) n + y L, (k-n) n &lt; Vh‘v χ ^ -Κν rhk Among them, ® represents the convolution operation symbol; &amp; represents the impulse response function of the first-order low-pass filter, and its conversion function is π⑺ = (卜 分 (卜 όζ_1), 6 = exP (-2 成 (), whose frequency The width is ~ mesh for the symbol rate 1 / T. 5. An improved pseudo-noise code tracking circuit suitable for a direct sequence spread spectrum communication system in an arbitrary variable-related multi-path fading channel, as described in the item of the scope of the patent application, in which the correlator 1 is rotated out, The error signal of one-to-one path will be generated by the discriminator. The error signal of these single paths will generate the timing error signal of the whole system by the highest signal-to-noise ratio combiner (MRC); among them, the data modulation effect on A The channel fading effect must be compensated by multiplying by the common complex number of &lt;; &lt; can effectively keep the error characteristics on each finger within the range of [-7 ;, 7;] to reduce itself The effect of interference; the (timing) error signal of the proposed technique, the lin correction code chasing circuit is accompanied by multiple interferences, which can be obtained by combining the domain score ratio with the drunken bribe, which can be expressed as follows: 30 1230521 MCTLIMPK Ck = Rc vi, k Among them, 0 means to perform a complex operation on a total number of vehicles; after some operations, the correction code follows the loop companion The (timing) error signal that interferes with multiple paths (where ~ = f) can be rewritten as: cMCTL, MPIC = ^ 5Γ〇_ 8η + 4Γ2 ~ Γ3) · (ε) 4 · (3Γ0-6Γ1 + 5Γ2 -3Γ3 + Γ4) .field) + (5Γ0-8Γ1 + 4Γ2-Γ3) · Yong) (7) where ^ (s) = g (eTc) {g [(^-\) TC]-g [(^ + \) TC]} · s2 (s) = g [(si) Tc] g [(^ \) rc] -g [(s ^ i) Tc] g [^-\ yc] s3 ^) ^ § [( ε + l) Tc] g [(£ + ifc] -g [(^-l) rc] g [(^-|) rc] 31 1230521 r3 = ZRe ^ a ^} V / 7 And here it must be noted that κϋ ;, and Γ are changed by the thinker's general effect, although there is no obvious sign k or t; if β /, ν / 5 β 疋 mean zero complex Gaussian random Variable, then its error characteristics, you can further its public 弋 strict / Hall ⑷, 处 Zheng Chucan) + 5 Gu)] Lu where <_> and clams are individually expressed as: the time average and the expected value of the operand, regardless of the channel label How to combine weighted Α, consider V / It can be said that non-co-correlated, co-correlated or arbitrary /, correlative in the multi-channel broadcast channel depends on cross-co-ordination, and its correction code repurchase path is accompanied by Xi Zhong path The (sequential) error signal and s-curve of interference cancellation have been proved to be indeed a common locking point relative to its existence, because Y2 (4 # 口 场) has this property. 32 1230521 6 · As described in item 5 of the scope of the patent application-an improved pseudo-noise code tracking circuit suitable for a direct sequence spread spectrum communication system in a multi-path fading channel with arbitrary variable correlation, wherein there is no multi-path The interference (canceled sequence) error signal of the same structure is called a correction code tracking loop, which can be re-derived and expressed as: MCTL Re Σ Uk -(τ〇- ^ ΗΓ2 ~ Γχ (ε) + {Γΰ_ΓιΚ (ε) where xc \ ^ \ Nh ^ Uk UE, k \ ^ k-(\ l2yP ~ n tl L7k = \ k-{\ l2Yp ~ n XC \ k-l-n \ N} ® If the channel label weighting is zero on average and independent of two pairs, the § curve of the correction code tracking loop can be rewritten as: Yan (Gen {{0}}} 吆 (deduction 3 (4 whose correction code tracks the loop (timing ) The error signal and the s-curve are oddly symmetric with respect to the same locking point at any channel condition; under the assumption that the channel label weighting is zero average and the two pairs are independent of each other, at each finger The (timing) error signal is still affected by the self-interference generated by the neighboring fingers 33! 23〇521. One of the items described in the scope of patent application No. 3, 4 or 5 is applicable to arbitrary variable-related multiples. An improved pseudo-noise code tracking loop of a direct-sequence spread-spectrum communication system in a fading channel behind the road. The error signal and error signal characteristic curve in the time-varying multipath channel have a stable and unique lock point and odd symmetry. Characteristic curve of error signal; this guarantees the absolute convergence properties of the invention's code tracking circuit, stable and steady-state operation, and robust introduction capability.