CN101567708B - Frequency offset compensation method and device - Google Patents

Abstract

The invention discloses a frequency offset compensation method, which comprises the following steps that: a base station performs frequency offset estimation on received uplink signals to obtain a frequency offset estimation result, and pre frequency offset compensation is performed on downlink signals according to the frequency offset estimation result; a terminal detects the frequency of the received downlink signals after the frequency offset compensation, the emission frequency of the uplink signals is determined according to the detected frequency of the downlink signals, and the uplink signals are emitted in the determined frequency; and a terminal side performs the pre frequency offset compensation by the same method. The invention also discloses a frequency offset compensation device, which comprises a frequency offset estimation module, a pre frequency offset compensation module and a frequency detection and frequency modulation module. The method and the device can effectively reduce the frequency offset of uplinks and downlinks, perform the frequency offset compensation of the uplinks and the downlinks, and not only reduce the relative frequency offset between the base station and the terminal, but also reduce frequency jump variable when the terminal switches between the base stations, so that both the base station and the terminal can correctly correct the receivedsignals to ensure communication quality.

Description

A kind of method and apparatus of compensate of frequency deviation

Technical field

The present invention relates to the compensate of frequency deviation technology, refer in particular to a kind of method and apparatus of compensate of frequency deviation.

Background technology

Code division multiple access (CDMA, Code Division Multiple Access) has that capacity is large, the anti-multipath fading ability strong and the band efficiency advantages of higher, become the main flow of 3G (Third Generation) Moblie Radio Transmission Technology, especially TD SDMA (TD-SCDMA, Time Division-Duplex SynchronousCode Division Multiple Access) and Wideband Code Division Multiple Access (WCDMA) (WCDMA, Wideband CodeDivision Multiple Access) extremely users' favor of system.

Along with building successively of highway, the continuous speed-raising of railway, the high-speed transit transportation has begun to use on a large scale, and the large step advances, thereupon, communicate professional terminal at bullet train also more and more, this just requires network that good telecommunication service quality can be provided.

In mobile communication system, owing to terminal is moving when sending message signale, so that the base station is kept in motion with respect to terminal.And when receiver and transmitter were in the motion state of given pace, the signal that receives had Doppler frequency shift, and particularly under the High-speed Circumstance, this frequency displacement is especially obvious.Doppler frequency shift can affect up access success rate, handover success rate, also can capacity and the covering of system be exerted an influence.

Base station amounts of frequency offset and speed of related movement are directly proportional, and the relation between the two is: $f_d=-\frac{f_0}{C}\×v\×\cos \mathrm{\θ}$ , wherein, f _dBe amounts of frequency offset; f ₀Centered by frequency, when base station and terminal communication, determine corresponding centre frequency, the base station sends downstream signal with the centre frequency of determining to this terminal all the time; V is the movement velocity of terminal; C is propagation velocity of electromagnetic wave; θ is the angle between the terminal direction of motion and the signal propagation direction.

At present, the movement velocity of the vehicles is generally in 150km/h～250km/h scope, development along with communications and transportation, in recent years, the speed that has successively many vehicles reaches 300～350km/h, and in this velocity interval, the Doppler frequency shift of terminal will be above 400Hz in the vehicles, therefore, base station and terminal must support enough compensate of frequency deviation technology could satisfy operation quality requirement.And estimate the frequency error between self and the transmitter and finish correction of frequency errors to be the function that receiver must be finished.

As shown in Figure 1, terminal receives f _dFrequency displacement, locking sends upward signal after the downstream signal frequencies, uplink receiving will have 2f _dFrequency displacement.Suppose that terminal moves with the speed of 300～350km/h, the reception signal frequency error of base station is the highest may to reach 1600Hz, so the impact of the frequency error of maximum 1600Hz must be had the ability to offset in the base station.

The direction of relative movement of terminal and base station is different, can produce positive and negative different frequency deviation, establishes f ₀The transmission frequency of base station, when terminal to away from the motion of the direction of base station the time, can produce negative frequency deviation-f _d, the frequency that terminal receives is f ₀-f _d, the frequency that the base station receives is f ₀-2f _dWhen terminal is moved to the direction of close base station, can produce positive frequency deviation f _d, the frequency that terminal receives is f ₀+ f _d, the frequency that the base station receives is f ₀+ 2f _dWhen terminal is moved between two base stations, when switching from a base station to another base station, terminal can frequency of occurrences saltus step, from frequency f ₀-f _dBe transferred to frequency f ₀+ f _d, terminal will have 2f _dFrequency hopping.Excessive frequency offset can cause communication quality to descend, and can cause service disruption in the time of serious.

If can not correctly estimate frequency deviation and compensate, systematic function will reduce greatly so, especially when frequency deviation is larger.Therefore seek good frequency bias compensation method significant.

Publication number is that the Chinese patent of CN1595829A discloses the method and apparatus that a kind of frequency deviation is estimated and compensated, and its basic thought is the frequency deviation value f that utilizes the front time slot to obtain ₀, compensate as the output symbol of initial value to current time slots; Then utilize the maximum likelihood method fine setting, export at last current frequency deviation value, use for next time slot, but still can not solve the problem that receives two times of frequency deviations and terminal frequency offset saltus step for up base station.

Publication number is mobile communication system and the method thereof that the Chinese patent of CN1859039A discloses a kind of reducing up channel Doppler effect, its basic thought is, to input a plurality of branch roads from the uplink channel signals of upper level, each branch road is according to different default frequency deviations, respectively it is carried out in various degree correcting frequency deviation, and comparison each tributary signal behind correcting frequency deviation, one road signal of optimum is exported to next stage.This scheme is the detection method of uplink frequency offset, do not solve the problem that reduces the receiving terminal frequency deviation, and complexity is high.

In a word, prior art is not still carried out the method for compensate of frequency deviation to downstream signal, and can not solve the problem of terminal frequency saltus step.This shows, seek a kind of uplink frequency offset compensation can carried out, can carry out again the downlink frequency offset compensation, and the method that can solve terminal frequency saltus step problem seems very important.

Summary of the invention

In view of this, main purpose of the present invention is to provide a kind of method and apparatus of compensate of frequency deviation, can effectively reduce the uplink downlink frequency deviation, carrying out the uplink downlink frequency deviation estimates and compensation, not only reduce the relative frequency deviation between base station and the terminal, and the frequency hopping amount of minimizing terminal, so that base station and terminal can both correctly be proofreaied and correct the signal that receives, guarantee communication quality.

For achieving the above object, technical scheme of the present invention is achieved in that

A kind of frequency bias compensation method, the method may further comprise the steps:

The base station is carried out frequency deviation to the terminal upward signal that receives and is estimated, according to frequency offset estimation result the downstream signal of described terminal is carried out pre-compensate of frequency deviation.

Further, the method also comprises:

The frequency of the downstream signal of terminal after to pre-compensate of frequency deviation detects, and determines the tranmitting frequency of upward signal according to detected downstream signal frequencies, and determined frequency is adjusted into self operating frequency, with determined frequency to the base station transmit uplink signal.

Further, describedly downstream signal is carried out compensate of frequency deviation be: pre-compensate of frequency deviation value is determined according to frequency offset estimation result in the base station; And with the centre frequency of default and pre-compensate of frequency deviation value sum as the downstream signal tranmitting frequency.

Preferably, when described terminal was moved away from the base station, described pre-compensate of frequency deviation value was for just; When described terminal was moved near the base station, described pre-compensate of frequency deviation value was for negative.

Preferably, the size of described pre-compensate of frequency deviation value satisfies: the absolute value of the Doppler frequency deviation value sum of described pre-compensate of frequency deviation value and descending generation is not more than the absolute value of the Doppler frequency deviation value of descending generation.

A kind of device of compensate of frequency deviation, this device comprises:

Frequency deviation estimating modules is used for that the terminal upward signal that receives is carried out frequency deviation and estimates, draws frequency offset estimation result;

Pre-compensate of frequency deviation module is used for according to the frequency offset estimation result that described frequency deviation estimating modules draws downstream signal being carried out pre-compensate of frequency deviation.

Preferably, this device further comprises:

Inspection frequency and frequency modulation module, for detection of the frequency that goes out the received downstream signal of after described pre-compensate of frequency deviation module is carried out pre-compensate of frequency deviation terminal, and determine the tranmitting frequency of upward signal according to detected downstream signal frequencies, determined frequency is adjusted into the terminal works frequency, make terminal with determined frequency to the base station transmit uplink signal.

Preferably, described pre-compensate of frequency deviation module further comprises:

Pre-compensate of frequency deviation value determining unit, the frequency offset estimation result that is used for drawing according to frequency deviation estimating modules is the pre-compensate of frequency deviation value that described terminal is determined in the base station;

The downstream signal transmitter unit is used for launching downstream signal as the tranmitting frequency of base station to terminal with the pre-compensate of frequency deviation value sum that pre-compensate of frequency deviation value determining unit is determined with the centre frequency of default.

Further, the size of the pre-compensate of frequency deviation value determined of described pre-compensate of frequency deviation value determining unit satisfies: the absolute value of the Doppler frequency deviation value sum of pre-compensate of frequency deviation value and descending generation is not more than the absolute value of the Doppler frequency deviation value of descending generation.

A kind of frequency bias compensation method, the method may further comprise the steps:

The downstream signal that send the base station that end-on is received carries out frequency deviation to be estimated, according to frequency offset estimation result upward signal is carried out pre-compensate of frequency deviation.

Further, describedly upward signal is carried out compensate of frequency deviation be: terminal is determined pre-compensate of frequency deviation value according to frequency offset estimation result; And with frequency that self was received and pre-compensate of frequency deviation value sum as the upward signal tranmitting frequency.

Further, when described terminal was moved away from the base station, described pre-compensate of frequency deviation value was for just; When described terminal was moved near the base station, described pre-compensate of frequency deviation value was for negative.

Preferably, the size of described pre-compensate of frequency deviation value satisfies: the absolute value of the Doppler frequency deviation value sum of described pre-compensate of frequency deviation value and up generation is not more than the absolute value of the Doppler frequency deviation value of up generation.

A kind of device of compensate of frequency deviation, this device comprises:

Frequency deviation estimating modules is used for that the downstream signal that send the base station that receives is carried out frequency deviation and estimates, draws frequency offset estimation result;

Pre-compensate of frequency deviation module is used for according to the frequency offset estimation result that described frequency deviation estimating modules draws upward signal being carried out pre-compensate of frequency deviation.

Preferably, described pre-compensate of frequency deviation module further comprises:

Pre-compensate of frequency deviation value determining unit, the frequency offset estimation result that is used for drawing according to frequency deviation estimating modules is that terminal is determined pre-compensate of frequency deviation value;

The upward signal transmitter unit, be used for the pre-compensate of frequency deviation value sum determined with the received frequency of terminal and pre-compensate of frequency deviation value determining unit as the tranmitting frequency of terminal to the base station transmit uplink signal.

Further, the size of the pre-compensate of frequency deviation value determined of described pre-compensate of frequency deviation value determining unit satisfies: the absolute value of the Doppler frequency deviation value sum of pre-compensate of frequency deviation value and up generation is not more than the absolute value of the Doppler frequency deviation value of up generation.

The method and apparatus of compensate of frequency deviation of the present invention has following characteristics and advantage:

(1) prior art can only be carried out the uplink frequency offset compensation, and downlink frequency offset compensation of the present invention is by the base station received upward signal to be carried out frequency deviation to estimate, obtain terminal uplink frequency offset estimated result, and with reference to the size of uplink frequency offset downstream signal is rectified a deviation in advance that compensation realizes, terminal detects the frequency of the downstream signal behind up pre-compensate of frequency deviation, determine the tranmitting frequency of upward signal according to detected downstream signal frequencies, the terminal works frequency is adjusted into determined frequency, with determined frequency transmit uplink signal, can reduce again the frequency deviation of upward signal.As seen, the present invention can reduce the frequency deviation of uplink receiving signal, and upward signal is compensated, and can reduce again the frequency deviation of down receiving signal, downstream signal is compensated, so just so that base station and terminal can both correctly be proofreaied and correct the signal that receives.

(2) method of employing compensate of frequency deviation of the present invention, effect is more obvious in the time of can making base station and terminal can both carry out having large frequency deviation under compensate of frequency deviation, the especially high-speed mobile environment; Because reducing of the in esse frequency deviation of receiving terminal alleviated the pressure that base station and terminal frequency are proofreaied and correct, greatly for telecommunication service quality provides reliable guarantee.

When (3) terminal was switched in the prior art, the frequency hopping amount was very large, terminal need to be with self frequency by original frequency hopping to the new frequency very large with the primary frequency size differences, this will cause very large pressure to terminal undoubtedly.And the present invention so that terminal is simpler aspect the hardware realization, reduces technical difficulty and the cost of terminal because greatly reducing the reduction terminal pressure of frequency hopping amount reduces the complexity of communication; Simultaneously, because present terminal technology uneven, the not too perfect terminal of some technology may ability not be finished so significantly frequency hopping and abort communication, and this will affect user's business experience.And greatly reducing of frequency hopping amount of the present invention with the specification requirement that greatly reduces terminal, so that nearly all terminal can both keep communication unimpeded in the existing market, strengthens user's business experience in high-speed mobile scene.

Description of drawings

Fig. 1 is the frequency deviation schematic diagram in the fast mobile terminal process;

Fig. 2 is the method flow schematic diagram that base station side of the present invention is carried out pre-compensate of frequency deviation;

Fig. 3 is the method flow schematic diagram that base station side of the present invention is carried out the first embodiment of pre-compensate of frequency deviation;

Fig. 4 is the method flow schematic diagram that base station side of the present invention is carried out the second embodiment of pre-compensate of frequency deviation;

Fig. 5 is the schematic diagram of the base station A of terminal the first embodiment of being carried out pre-compensate of frequency deviation by base station side receive frequency during to the base station B switch instances of the second embodiment;

Fig. 6 is the method flow schematic diagram that base station side of the present invention is carried out the 3rd embodiment of pre-compensate of frequency deviation;

Fig. 7 is the method flow schematic diagram that base station side of the present invention is carried out the 4th embodiment of pre-compensate of frequency deviation;

Fig. 8 is the schematic diagram of the base station A of terminal the 3rd embodiment that carried out pre-compensate of frequency deviation by base station side receive frequency during to the base station B switch instances of the 4th embodiment;

Fig. 9 is the device schematic diagram that base station side of the present invention is carried out pre-compensate of frequency deviation;

Figure 10 is the method flow schematic diagram that end side of the present invention is carried out pre-compensate of frequency deviation;

Figure 11 is the device schematic diagram that end side of the present invention is carried out pre-compensate of frequency deviation.

Embodiment

The present invention is mainly used under the high-speed mobile scene, and its basic thought is: at first, the frequency deviation estimation is carried out to received upward signal in the base station, obtains terminal k uplink frequency offset estimated result

And according to

Downstream signal is carried out pre-compensate of frequency deviation; Described terminal detects behind the compensate of frequency deviation frequency of self received downstream signal, determine the tranmitting frequency of upward signal according to detected downstream signal frequencies, self operating frequency is adjusted into determined frequency, with determined frequency to the base station transmit uplink signal; If end side is wanted proportion precompensation technology, the end side method of carrying out pre-compensate of frequency deviation and the base station side method of carrying out compensate of frequency deviation is identical so.

The present invention is further detailed explanation below in conjunction with accompanying drawing.

The method flow that base station side of the present invention is carried out pre-compensate of frequency deviation may further comprise the steps as shown in Figure 2:

The upward signal that send the terminal k that receives step 201, base station carries out frequency deviation to be estimated, obtains frequency offset estimation result Wherein, k represent the base station for k terminal;

If the frequency offset estimation result that terminal obtains is

f _{D, k}Just be used for representing the symbol of frequency deviation, F _{D, k}Estimated value, be the symbol that represents the frequency deviation estimated.Because base station transmit signals is short to the time compole that receives signal demand, according to the frequency offset calculation formula $f_d=-\frac{f_0}{C}\×v\×\cos \mathrm{\θ},$ Everyly in the formula almost do not change in the short time at the utmost point, so the approximate frequency deviation of thinking that downstream signal produces equates with the frequency deviation of upward signal generation in following step, be f _{D, k}Because frequency deviation can just can be born, so f _{D, k}Value can just can bear, when terminal is moved away from the base station, f _{D, k}Value be negative, when terminal near base station when motion, f _{D, k}Value be positive number.

Step 202, base station are according to the frequency offset estimation result that obtains

Set pre-compensate of frequency deviation value f _{Pre, k}, with the centre frequency f of default ₀With pre-compensate of frequency deviation value f _{Pre, k}Sum f ₀+ f _{Pre, k}Send downstream signal as base station down signal tranmitting frequency to described terminal k; Wherein, f ₀The centre frequency of base station work, when terminal is moved away from the base station, f _{Pre, k}For just; When terminal is moved near the base station, f _{Pre, k}For negative.

In the communication system, the frequency that the downstream signal of terminal is mail in the base station is fixed, all the time with centre frequency f ₀Send downstream signal to terminal, key of the present invention is, sets pre-frequency deviation estimated value, with f ₀With pre-compensate of frequency deviation value f _{Pre, k}Sum f ₀+ f _{Pre, k}Send downstream signal as the downstream signal tranmitting frequency to described terminal k.f _{Pre, k}Value and frequency offset estimation result

It is relevant, $f_{\mathrm{pre},k}=f\left({\hat{f}}_{d,k}\right),$ Wherein, f representative function, f _{Pre, k}Be

Function.Function $f_{\mathrm{pre},k}=f\left({\hat{f}}_{d,k}\right)$ Concrete form has a variety of, as long as can make terminal frequency offset f _{Dl, k}Satisfy | f _{Dl, k}|≤| f _{D, k}|, wherein, f _{Dl, k}=f _{Pre, k}+ f _{D, k}, reduce the actual frequency deviation that receives and get final product.

For example, function $f_{\mathrm{pre},k}=f\left({\hat{f}}_{d,k}\right)$ Form can be got

$f_{\mathrm{pre},k}=-\mathrm{\α}{\hat{f}}_{d,k},---\left(1\right)$

Wherein, α is the positive number less than or equal to 1, represents not carry out compensate of frequency deviation when α is zero, mainly is α ≠ 0 and the present invention uses, but less than or equal to 1 situation;

Functional form also can be got $f_{\mathrm{pre},k}={\hat{f}}_{d,k}-C,$ Wherein, C is constant, can just can bear, but C just in time with

Positive and negative opposite, purpose is partly or entirely to offset the frequency deviation that produces, the situation of C=0 represents not carry out pre-frequency deviation adjustment, and the present invention uses mainly is $\left|C\right|<\left|{\hat{f}}_{d,k}\right|$ Situation.

Step 203, described terminal k receive the downstream signal from the base station, and detect the frequency of the downstream signal behind the compensate of frequency deviation, determine the tranmitting frequency of upward signal according to detected downstream signal frequencies, determined frequency is adjusted into self operating frequency, with determined frequency to the base station transmit uplink signal.

Here, the frequency offset estimation result of the downstream signal that receives of described terminal is

And the theoretical value of downstream signal frequency deviation is f _{Dl, k}=f _{Pre, k}+ f _{D, k},

Be f _{Dl, k}Estimated value, ${\hat{f}}_{\mathrm{dl},k}\&ap;f_{\mathrm{dl},k};$

So the detected frequency of terminal is f behind the compensate of frequency deviation _Ue, $f_{\mathrm{ue}}=f_0+{\hat{f}}_{\mathrm{dl},k}\text{\&ap;}{f}_0+f_{\mathrm{pre},k}+f_{d,k},$ Because f _{Pre, k}Offset part or all of frequency deviation, so f _UeThe absolute value of frequency deviation less than f _{D, k}Absolute value.

Described terminal can directly be adjusted into self operating frequency with detected frequency after detecting the frequency of downstream signal, send upward signal with detected frequency to the base station; Also can determine the upward signal tranmitting frequency according to detected frequency, for example detected frequency be multiply by certain coefficient, and determined frequency is adjusted into self operating frequency, send upward signal with determined frequency to the base station, concrete terminal determines that according to detected frequency the method for upward signal tranmitting frequency belongs to prior art, does not repeat them here.But no matter terminal sends upward signal with the sort of frequency to the base station, all can solve the problem that the base station receives two times of frequency deviations.In the following description, for the convenience that illustrates, describe to base station transmission downstream signal as example take the frequency that direct-detection goes out with terminal.

Described terminal is at f _UeSend upward signal on the frequency to the base station, and the base station actual frequency that receives next time is f _Ue+ f _{D, k}≈ f ₀+ f _{Pre, k}+ 2f _{D, k}And | f _{Pre, k}+ 2f _{D, k}|≤| 2f _{D, k}|, because f _{Pre, k}Part or whole f have been offset _{D, k}, as seen, the invention solves under the high-speed cruising base station excessive because receiving two times of frequency deviations, cause the correctly problem of restituted signal.

Base station or terminal circulation execution in step 201 that is to say to step 203, and upward signal of the every transmission of terminal will carry out once pre-compensate of frequency deviation, so repeat, until stop communication between described terminal and the base station.

In the above description, terminal k represent the base station for any one terminal, so terminal k has generality, namely the base station for any one terminal all adopt said method and base station to carry out alternately.

In order to illustrate that the present invention is the problem that how to reduce uplink downlink frequency deviation and terminal frequency offset saltus step, choosing two embodiment describes, embodiment one is that terminal is during away from base station A, α in the formula (1) is taken as at 1 o'clock, the method of compensate of frequency deviation, when embodiment two is the close base station B of terminal, α in the formula (1) is taken as at 1 o'clock, the method of compensate of frequency deviation, then in conjunction with two embodiment illustrate when terminal when being switched to base station B by base station A, how to solve the problem of terminal frequency offset saltus step when of the present invention.

Base station side of the present invention carry out pre-compensate of frequency deviation the first embodiment method flow as shown in Figure 3, may further comprise the steps:

Step 301, base station A are carried out frequency deviation to the upward signal of the terminal that receives and are estimated, obtain the value of frequency offset estimation result, namely obtain the frequency deviation estimated value and are

Step 302, base station A are according to the frequency deviation estimated value that obtains

Set pre-compensate of frequency deviation value f _Pre, the present $f_{\mathrm{pre}}={\hat{f}}_d,$ With f ₀With pre-compensate of frequency deviation value f _{Pre, k}Sum $f_0+f_{\mathrm{pre}}=f_0+{\hat{f}}_d$ Send downstream signal as the downstream signal tranmitting frequency to described terminal;

Step 303, described terminal receive downstream signal, and detect the frequency of the downstream signal behind the compensate of frequency deviation, and operating frequency is adjusted into detected frequency, and send upward signal with this operating frequency to base station A.

Here, the frequency deviation estimated value of the downstream signal that receives of described terminal is

And the theoretical value of downstream signal frequency deviation is f _{Dl, A}=f _Pre-f _d,

Be f _{Dl, A}Estimated value, ${\hat{f}}_{\mathrm{dl},A}\&ap;f_{\mathrm{dl},A}=f_{\mathrm{pre}}-f_d={\hat{f}}_d{-f}_d=0,$ As can be known, this moment terminal the frequency deviation estimated value

Absolute value less than f _dAbsolute value.

So the detected frequency of terminal is f behind the compensate of frequency deviation _{Ue, A}, $f_{\mathrm{ue},A}=f_0-{\hat{f}}_{\mathrm{dl},A}\&ap;f_0,$ This frequency departure base station center frequency is less than the downlink frequency offset-f that does not do pre-correction _d

Because described terminal is at f _{Ue, A}Send upward signal to base station A on the frequency, so base station A next time, the actual frequency that receives was f _{Ue, A}-f _d=f ₀-f _d, here, frequency deviation is-f _dAbsolute value less than-2f _dAbsolute value, greatly reduce the maximum capacity requirement of base station A compensate of frequency deviation.

Base station side of the present invention carry out pre-compensate of frequency deviation the second embodiment method flow as shown in Figure 4, may further comprise the steps:

The upward signal that step 401, base station B send terminal carries out frequency deviation to be estimated, obtains the frequency deviation estimated value and is

Step 402, base station B are according to resulting frequency deviation estimated value Set pre-compensate of frequency deviation value f _Pre, order $f_{\mathrm{pre}}=-{\hat{f}}_d,$ And with f ₀With pre-compensate of frequency deviation value f _{Pre, k}Sum $f_0+f_{\mathrm{pre}}=f_0-{\hat{f}}_d$ Send downstream signal as the downstream signal tranmitting frequency to described terminal;

Step 403, described terminal receive downstream signal, and detect the frequency of the downstream signal behind the compensate of frequency deviation, and operating frequency is adjusted into detected frequency, and send upward signal with this operating frequency to base station B.

Wherein, the frequency deviation estimated value of the downstream signal that receives of described terminal is

And the theoretical value of downstream signal frequency deviation is f _{Dl, B}=f _Pre+ f _d,

Be f _{Dl, B}Estimated value, ${\hat{f}}_{\mathrm{dl},B}\&ap;f_{\mathrm{dl},B}=f_{\mathrm{pre}}+f_d=-{\hat{f}}_d+f_d=0,$ As can be known, this moment terminal the frequency deviation estimated value

Less than f _d

So the detected frequency of terminal is f behind the compensate of frequency deviation _{Ue, B}, $f_{\mathrm{ue},B}=f_0+{\hat{f}}_{\mathrm{dl},B}\&ap;f_0,$ This frequency departure base station center frequency is less than the downlink frequency offset f that does not do pre-correction _d

Terminal can be at f _{Ue, B}Send upward signal to base station B on the frequency, so the frequency that base station B receives next time is f _{Ue, B}+ f _d=f ₀+ f _d, frequency deviation is f _dAbsolute value less than 2f _dAbsolute value, greatly reduce the maximum capacity requirement of base station compensate of frequency deviation.

The schematic diagram that terminal of the present invention is switched to base station B by base station A as shown in Figure 5, in conjunction with the embodiments one and embodiment two, when supposing that described terminal is switched to base station B by base station A, the frequency of terminal reception from $f_{\mathrm{ue},A}=f_0-{\hat{f}}_{\mathrm{dl},A}\&ap;f_0$ Jump to $f_{\mathrm{ue},B}=f_0+{\hat{f}}_{\mathrm{dl},B}\&ap;f_0,$ The frequency hopping amount is almost nil, the frequency hopping amount 2f when not doing pre-compensate of frequency deviation much smaller than downstream signal _d

Among two above embodiment, pre-compensate of frequency deviation value is got ± f _d, namely the α in the formula (1) gets 1, and the below gets less than further specifying implementation of the present invention at 1 o'clock with the value of α.Embodiment three is terminals during away from base station A, and the α that gets in the formula (1) is

The time, the method for compensate of frequency deviation, when embodiment four was the close base station B of terminal, the α that gets in the formula (1) was

The time, the method for compensate of frequency deviation, then in conjunction with two embodiment illustrate when terminal when being switched to base station B by base station A, how to solve the problem of terminal frequency offset saltus step when of the present invention.

Base station side of the present invention carry out pre-compensate of frequency deviation the 3rd embodiment method flow as shown in Figure 6, may further comprise the steps:

Step 601, base station A are carried out frequency deviation to the upward signal of the terminal that receives and are estimated, obtain the frequency deviation estimated value and are

Step 602, base station A are according to the frequency deviation estimated value that obtains Set pre-compensate of frequency deviation value f _Pre, order $f_{\mathrm{pre}}=\frac{{\hat{f}}_{\mathrm{<figure-callout\; id="2"\; label="d"\; filenames="S2008101046543E00042.png"\; state="\{\{state\}\}">d</figure-callout>}}}{2},$ And with f ₀With pre-compensate of frequency deviation value f _{Pre, K}Sum $f_0+f_{\mathrm{pre}}=f_0+\frac{{\hat{f}}_{\mathrm{<figure-callout\; id="2"\; label="d"\; filenames="S2008101046543E00042.png"\; state="\{\{state\}\}">d</figure-callout>}}}{2}$ Send downstream signal as the downstream signal tranmitting frequency to described terminal;

Step 603, described terminal receive downstream signal, and detect the frequency of downstream signal behind the compensate of frequency deviation, operating frequency is adjusted into detected frequency, and sends upward signal with this operating frequency to base station A.

Here, the frequency deviation estimated value of the downstream signal that receives of described terminal is

${\hat{f}}_{\mathrm{dl},A}\&ap;f_{\mathrm{pre}}-f_d=\frac{{\hat{f}}_d}{2}-f_d\&ap;-\frac{{\mathrm{<figure-callout\; id="2"\; label="f\; d"\; filenames="S2008101046543E00042.png"\; state="\{\{state\}\}">f</figure-callout>}}_d}{2},$ As can be known, this moment terminal the frequency deviation estimated value

Less than-f _d

So the detected frequency of terminal is f behind the compensate of frequency deviation _{Ue, A}, $f_{\mathrm{ue},A}=f_0+{\hat{f}}_{\mathrm{dl},A}\&ap;f_0-\frac{{\mathrm{<figure-callout\; id="2"\; label="f\; d"\; filenames="S2008101046543E00042.png"\; state="\{\{state\}\}">f</figure-callout>}}_d}{2},$ This frequency departure base station center frequency is less than the downlink frequency offset f that does not do pre-correction _d

Because described terminal is at f _{Ue, A}Send upward signal to base station A on the frequency, so base station A next time, the actual frequency that receives was $f_{\mathrm{ue},A}-f_d=f_0-\frac{f_d}{2}-f_d=f_0-\frac{{3\mathrm{<figure-callout\; id="2"\; label="f\; d"\; filenames="S2008101046543E00042.png"\; state="\{\{state\}\}">f</figure-callout>}}_d}{2},$ Here, frequency deviation is

Absolute value less than-2f _dAbsolute value, greatly reduce the maximum capacity requirement of base station A compensate of frequency deviation.

Base station side of the present invention carry out pre-compensate of frequency deviation the second embodiment method flow as shown in Figure 7, may further comprise the steps:

The upward signal that step 701, base station B send terminal carries out frequency deviation to be estimated, obtains the frequency deviation estimated value and is

Step 702, base station B are according to resulting frequency deviation estimated value

Set pre-compensate of frequency deviation value f _Pre, order $f_{\mathrm{pre}}=-\frac{{\hat{f}}_{\mathrm{<figure-callout\; id="2"\; label="d"\; filenames="S2008101046543E00042.png"\; state="\{\{state\}\}">d</figure-callout>}}}{2},$ And with f ₀With pre-compensate of frequency deviation value f _{Pre, K}Sum $f_0+f_{\mathrm{pre}}=f_0-\frac{{\hat{f}}_{\mathrm{<figure-callout\; id="2"\; label="d"\; filenames="S2008101046543E00042.png"\; state="\{\{state\}\}">d</figure-callout>}}}{2}$ Send downstream signal as the downstream signal tranmitting frequency to described terminal;

Step 703, described terminal receive downstream signal, and detect the frequency of the downstream signal behind the compensate of frequency deviation, and operating frequency is adjusted into detected frequency, and send upward signal with this operating frequency to base station B.

Wherein, the frequency deviation estimated value of the downstream signal that receives of described terminal is

${\hat{f}}_{\mathrm{dl},B}\&ap;f_{\mathrm{pre}}+f_d=-\frac{{\hat{f}}_{\mathrm{<figure-callout\; id="2"\; label="d"\; filenames="S2008101046543E00042.png"\; state="\{\{state\}\}">d</figure-callout>}}}{2}+f_d\&ap;\frac{{\mathrm{<figure-callout\; id="2"\; label="f\; d"\; filenames="S2008101046543E00042.png"\; state="\{\{state\}\}">f</figure-callout>}}_d}{2},$ As can be known, this moment terminal the frequency deviation estimated value

Absolute value less than f _dAbsolute value.

So the detected frequency of terminal is f behind the compensate of frequency deviation _{Ue, B}, $f_{\mathrm{ue},B}=f_0+\frac{{\mathrm{<figure-callout\; id="2"\; label="f\; d"\; filenames="S2008101046543E00042.png"\; state="\{\{state\}\}">f</figure-callout>}}_d}{2},$ This frequency departure base station center frequency is less than the downlink frequency offset f that does not do pre-correction _d

Terminal can be at f _{Ue, B}Send upward signal to base station B on the frequency, so the frequency that base station B receives next time is $f_{\mathrm{ue},B}+f_d=f_0+\frac{{\mathrm{<figure-callout\; id="2"\; label="f\; d"\; filenames="S2008101046543E00042.png"\; state="\{\{state\}\}">f</figure-callout>}}_d}{2}+f_d=f_0+\frac{{3\mathrm{<figure-callout\; id="2"\; label="f\; d"\; filenames="S2008101046543E00042.png"\; state="\{\{state\}\}">f</figure-callout>}}_d}{2},$ Frequency deviation is

Absolute value less than 2f _dAbsolute value, greatly reduce the maximum capacity requirement of base station compensate of frequency deviation.

α is in the formula of the present invention (1)

The time, the schematic diagram that terminal is switched to base station B by base station A as shown in Figure 8, in conjunction with the embodiments three and embodiment four, when supposing that described terminal is switched to base station B by base station A, the frequency of terminal reception from $f_{\mathrm{ue},A}=f_0-{\hat{f}}_{\mathrm{dl},A}\&ap;f_0-\frac{{\mathrm{<figure-callout\; id="2"\; label="f\; d"\; filenames="S2008101046543E00042.png"\; state="\{\{state\}\}">f</figure-callout>}}_d}{2}$ Jump to $f_{\mathrm{ue},B}=f_0+{\hat{f}}_{\mathrm{dl},B}\&ap;f_0+\frac{{\mathrm{<figure-callout\; id="2"\; label="f\; d"\; filenames="S2008101046543E00042.png"\; state="\{\{state\}\}">f</figure-callout>}}_d}{2},$ The frequency hopping amount is about f _d, the frequency hopping amount 2f when not doing pre-compensate of frequency deviation much smaller than downstream signal _d

The device that base station side of the present invention is carried out pre-compensate of frequency deviation comprises as shown in Figure 9 with lower module: frequency deviation estimating modules 91, pre-compensate of frequency deviation module 92, inspection frequently and frequency modulation module 93, wherein,

Frequency deviation estimating modules 91 is used for the upward signal that receiving terminal sends and the upward signal that receives is carried out frequency deviation estimate, draws the frequency deviation estimated value.

If terminal is in frequency f _UeOwing to fast mobile terminal, there is Doppler frequency deviation f in the upper upward signal that sends to the base station in the link _{D, k}, the frequency that the base station receives in theory is f=f _Ue+ f _{D, k}, and the base station detects this moment frequency deviation estimating modules 91 of self receiving and can calculate frequency offset estimation result and be ${\hat{f}}_{d,k}\&ap;f-{f_{\mathrm{ue}}}^{\&prime;}.$ Wherein, f _{D, k}Just be used for representing the symbol of frequency deviation,

It is the symbol that represents the frequency deviation estimated.Identical with the method part, the approximate frequency deviation of thinking that downstream signal produces equates with the frequency deviation that upward signal produces in following module, is f _{D, k}Because frequency deviation can just can be born, so f _{D, k}Value can just can bear, when terminal is moved away from the base station, f _{D, k}Value be negative, when terminal near base station when motion, f _{D, k}Value be positive number.

Pre-compensate of frequency deviation module 92 is used for according to the frequency offset estimation result that frequency deviation estimating modules 91 draws downstream signal being carried out compensate of frequency deviation.

The frequency offset estimation result that pre-compensate of frequency deviation module 92 draws according to frequency deviation estimating modules 91 Set pre-compensate of frequency deviation value f _{Pre, k}, so that the base station is with centre frequency f ₀Add pre-compensate of frequency deviation value f _{Pre, k}The frequency values f that obtains ₀+ f _{Pre, k}Send downstream signal to described terminal k.

Described pre-compensate of frequency deviation module 92 further comprises: pre-compensate of frequency deviation value determining unit 921 and frequency determine to reach downstream signal transmitter unit 922, and wherein, pre-compensate of frequency deviation value determining unit 921 is for the frequency offset estimation result that draws according to frequency deviation estimating modules 91

For determining pre-compensate of frequency deviation value in the base station.Here, pre-compensate of frequency deviation value f _{Pre, k}Value relevant with the uplink frequency offset estimated result, $f_{\mathrm{pre},k}=f\left({\hat{f}}_{d,k}\right),$ Wherein, f representative function, f _{Pre, k}Be

Function; Here, function $f_{\mathrm{pre},k}=f\left({\hat{f}}_{d,k}\right)$ Concrete form has a variety of, as long as can make terminal receive downstream signal frequency deviation f _{Dl, k}Satisfy | f _{Dl, k}|≤| f _{D, k}|, f wherein _{Dl, k}=f _{Pre, k}+ f _{D, k}, reduce the actual frequency deviation that receives and get final product.

For example, function $f_{\mathrm{pre},k}=f\left({\hat{f}}_{d,k}\right)$ Form can be got equally $f_{\mathrm{pre},k}=-\mathrm{\&alpha;}{\hat{f}}_{d,k},$ Or get $f_{\mathrm{pre},k}={\hat{f}}_{d,k}-C$ Deng, the explanation of concrete every square method part of value in the formula.

Frequency is determined and downstream signal transmitter unit 922 is used for launching downstream signal as the tranmitting frequency of base station to terminal with pre-compensate of frequency deviation value determining unit 921 determined pre-compensate of frequency deviation value sums with the centre frequency of default.

Inspection frequency and frequency modulation module 93, for detection of going out the frequency of carrying out the received downstream signal of terminal k behind the compensate of frequency deviation through pre-compensate of frequency deviation module 92, determine the tranmitting frequency of upward signal according to the frequency of detected downstream signal, determined frequency is adjusted into the terminal works frequency, make terminal with determined frequency to the base station transmit uplink signal.

Here, the frequency offset estimation result of the downstream signal that receives of described terminal k is And the theoretical value of downstream signal frequency deviation is f _{Dl, k}=f _{Pre, k}+ f _{D, k},

Be f _{Dl, k}Estimated value, ${\hat{f}}_{\mathrm{dl},k}\&ap;f_{\mathrm{dl},k};$

So the frequency that inspection frequency and frequency modulation module 93 detected described terminal k receive behind the compensate of frequency deviation is f _Ue, $f_{\mathrm{ue}}=f_0+{\hat{f}}_{\mathrm{dl},k}\&ap;f_0+f_{\mathrm{pre},k}+f_{d,k},$ This frequency departure base station center frequency is less than the downlink frequency offset f that does not do pre-correction _{D, k}

Inspection frequently and frequency modulation module 93 so that described terminal according to detected downstream signal frequencies f _UeDetermine the upward signal tranmitting frequency, send upward signal with determined frequency to the base station, suppose that terminal is directly with detected downstream signal frequencies f _UeBe adjusted into self operating frequency, send upward signal with detected frequency to the base station, then the base station actual frequency that receives next time is f _Ue+ f _{D, k}≈ f ₀+ f _{Pre, k}+ 2f _{D, k}, and | f _{Pre, k}+ 2f _{D, k}|≤| 2f _{D, k}|, because f _{Pre, k}A part or whole f have been offset _{D, k}As seen, the invention solves under the high-speed cruising base station excessive because receiving two times of frequency deviations, cause the correctly problem of restituted signal.Simultaneously, because the base station receives two times of frequency deviation solution of problems, the problem of frequency hopping had also obtained good solution when terminal was switched between two base stations, asked for an interview top embodiment, did not repeat them here.

In above module, frequency deviation estimating modules 91, pre-compensate of frequency deviation module 92 are positioned at base station one side, and inspection frequency and frequency modulation module 93 are positioned at terminal one side, and inspection frequency and frequency modulation module 93 belong to optional module.

This shows, adopt the method and apparatus of compensate of frequency deviation of the present invention, come downstream signal is rectified a deviation in advance by estimating the upward signal frequency deviation, terminal detects the frequency of the downstream signal behind the compensate of frequency deviation, determine the tranmitting frequency of upward signal according to detected downstream signal frequencies, self operating frequency is adjusted into determined frequency, with determined frequency to the base station transmit uplink signal, like this, just reduced the frequency deviation of uplink downlink, because the minimizing of up-downgoing frequency deviation, when terminal was switched between the base station, the frequency hopping amount also reduced thereupon, so that no matter the terminal of compensating for frequency offset ability power can both well be applicable to network, effectively reduce technical difficulty and production cost that terminal produces because proofreading and correct frequency deviation, also strengthened the compatibility of network to terminal.

Above-mentioned method at the pre-compensate of frequency deviation of base station side can be applied to end side equally, and terminal also can be carried out the uplink frequency offset compensation according to downstream signal frequency deviation estimated value when sending upward signal, with reduce the base station received the frequency deviation of upward signal.The method flow that end side of the present invention is carried out pre-compensate of frequency deviation mainly may further comprise the steps as shown in figure 10:

The downstream signal that step 1001, terminal k send the base station that receives carries out frequency deviation to be estimated, obtains frequency offset estimation result

If the frequency offset estimation result that terminal k obtains is

f _{D, k}' just be used for representing the symbol of frequency deviation,

F _{D, k}' estimated value, be the symbol that represents the frequency deviation estimated.

Step 1002, terminal k are according to the frequency offset estimation result that obtains Set pre-compensate of frequency deviation value f _{Pre, k}', with self received frequency and pre-compensate of frequency deviation value f _{Pre, k}' sum sends upward signal as terminal upward signal tranmitting frequency to described base station;

Here, end side is set pre-compensate of frequency deviation value f _{Pre, k}' method and base station side set pre-compensate of frequency deviation value f _{Pre, k}Method identical, do not repeat them here.

Downstream signal of the every reception of terminal k will carry out once pre-compensate of frequency deviation, so repeat, until stop communication between described terminal and the base station.

Here, terminal k represent the base station for any one terminal, so terminal k has generality, namely the base station for any one terminal all adopt said method and base station to carry out alternately.

The device that end side of the present invention is carried out pre-compensate of frequency deviation comprises as shown in figure 11 with lower module: frequency deviation estimating modules 111, pre-compensate of frequency deviation module 112, wherein,

Frequency deviation estimating modules 111 for receiving the downstream signal of sending the base station and the downstream signal that receives being carried out frequency deviation estimate, draws the frequency deviation estimated value.

Pre-compensate of frequency deviation module 112 is used for according to the frequency offset estimation result that frequency deviation estimating modules 91 draws upward signal being carried out compensate of frequency deviation.

Here, pre-compensate of frequency deviation module 112 in end side according to the pre-compensate of frequency deviation value f that sets _{Pre, k}The method that compensate of frequency deviation is carried out in ' method and the base station of carrying out compensate of frequency deviation is identical, does not repeat them here.

Described pre-compensate of frequency deviation module 112 further comprises: pre-compensate of frequency deviation value determining unit 1121 and frequency determine to reach upward signal transmitter unit 1122, and wherein, pre-compensate of frequency deviation value determining unit 1121 is for the frequency offset estimation result that draws according to frequency deviation estimating modules 91

For terminal is determined pre-compensate of frequency deviation value.

Frequency is determined and upward signal transmitter unit 1122 is used for the received frequency of terminal self and pre-compensate of frequency deviation value determining unit 1121 determined pre-compensate of frequency deviation value sums as the tranmitting frequency of terminal to the base station transmit uplink signal.

In addition, the compensate of frequency deviation that the present invention also can carry out base station side and end side combines, to carry out compensate of frequency deviation in base station side, terminal is after receiving the base station and carrying out the frequency of compensate of frequency deviation, carry out compensate of frequency deviation in self this side, the method of concrete compensation is seen the explanation of each part mentioned above, does not repeat them here.

The above is preferred embodiment of the present invention only, is not for limiting protection scope of the present invention.

Claims (10)

1. a frequency bias compensation method is characterized in that, the method may further comprise the steps:

The base station is carried out frequency deviation to the terminal upward signal that receives and is estimated, according to frequency offset estimation result the downstream signal of described terminal is carried out pre-compensate of frequency deviation, wherein, describedly downstream signal is carried out compensate of frequency deviation be: pre-compensate of frequency deviation value is determined according to frequency offset estimation result in the base station; And with the centre frequency of default and pre-compensate of frequency deviation value sum as the downstream signal tranmitting frequency;

The frequency of the downstream signal of terminal after to pre-compensate of frequency deviation detects, and determines the tranmitting frequency of upward signal according to detected downstream signal frequencies, and determined frequency is adjusted into self operating frequency, with determined frequency to the base station transmit uplink signal.

2. method according to claim 1 is characterized in that, when described terminal was moved away from the base station, described pre-compensate of frequency deviation value was for just; When described terminal was moved near the base station, described pre-compensate of frequency deviation value was for negative.

3. method according to claim 2 is characterized in that, the size of described pre-compensate of frequency deviation value satisfies: the absolute value of the Doppler frequency deviation value sum of described pre-compensate of frequency deviation value and descending generation is not more than the absolute value of the Doppler frequency deviation value of descending generation.

4. the device of a compensate of frequency deviation is characterized in that, this device comprises:

Frequency deviation estimating modules is used for that the terminal upward signal that receives is carried out frequency deviation and estimates, draws frequency offset estimation result;

Pre-compensate of frequency deviation module is used for according to the frequency offset estimation result that described frequency deviation estimating modules draws downstream signal being carried out pre-compensate of frequency deviation;

Inspection frequency and frequency modulation module, for detection of the frequency that goes out the received downstream signal of after described pre-compensate of frequency deviation module is carried out pre-compensate of frequency deviation terminal, and determine the tranmitting frequency of upward signal according to detected downstream signal frequencies, determined frequency is adjusted into the terminal works frequency, make terminal with determined frequency to the base station transmit uplink signal;

Wherein, described pre-compensate of frequency deviation module further comprises:

Pre-compensate of frequency deviation value determining unit, the frequency offset estimation result that is used for drawing according to frequency deviation estimating modules is the pre-compensate of frequency deviation value that described terminal is determined in the base station;

The downstream signal transmitter unit is used for launching downstream signal as the tranmitting frequency of base station to terminal with the pre-compensate of frequency deviation value sum that pre-compensate of frequency deviation value determining unit is determined with the centre frequency of default.

5. device according to claim 4, it is characterized in that, the size of the pre-compensate of frequency deviation value that described pre-compensate of frequency deviation value determining unit is determined satisfies: the absolute value of the Doppler frequency deviation value sum of pre-compensate of frequency deviation value and descending generation is not more than the absolute value of the Doppler frequency deviation value of descending generation.

6. a frequency bias compensation method is characterized in that, the method may further comprise the steps:

The downstream signal that send the base station that end-on is received carries out frequency deviation to be estimated, according to frequency offset estimation result upward signal is carried out pre-compensate of frequency deviation;

Wherein, describedly upward signal is carried out compensate of frequency deviation be: terminal is determined pre-compensate of frequency deviation value according to frequency offset estimation result; And with frequency that self was received and pre-compensate of frequency deviation value sum as the upward signal tranmitting frequency.

7. method according to claim 6 is characterized in that, when described terminal was moved away from the base station, described pre-compensate of frequency deviation value was for just; When described terminal was moved near the base station, described pre-compensate of frequency deviation value was for negative.

8. method according to claim 7 is characterized in that, the size of described pre-compensate of frequency deviation value satisfies: the absolute value of the Doppler frequency deviation value sum of described pre-compensate of frequency deviation value and up generation is not more than the absolute value of the Doppler frequency deviation value of up generation.

9. the device of a compensate of frequency deviation is characterized in that, this device comprises:

Frequency deviation estimating modules is used for that the downstream signal that send the base station that receives is carried out frequency deviation and estimates, draws frequency offset estimation result;

Pre-compensate of frequency deviation module is used for according to the frequency offset estimation result that described frequency deviation estimating modules draws upward signal being carried out pre-compensate of frequency deviation;

Wherein, described pre-compensate of frequency deviation module further comprises:

Pre-compensate of frequency deviation value determining unit, the frequency offset estimation result that is used for drawing according to frequency deviation estimating modules is that terminal is determined pre-compensate of frequency deviation value;

The upward signal transmitter unit, be used for the pre-compensate of frequency deviation value sum determined with the received frequency of terminal and pre-compensate of frequency deviation value determining unit as the tranmitting frequency of terminal to the base station transmit uplink signal.

10. device according to claim 9, it is characterized in that, the size of the pre-compensate of frequency deviation value that described pre-compensate of frequency deviation value determining unit is determined satisfies: the absolute value of the Doppler frequency deviation value sum of pre-compensate of frequency deviation value and up generation is not more than the absolute value of the Doppler frequency deviation value of up generation.

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