CN101212430B - Channel estimating method and its device - Google Patents
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Abstract
The invention relates to a channel estimation method and a device thereof, which is used in a wireless communication system; the method comprises the steps: stability of power change is divided into a plurality of grades; a corresponding channel estimation algorithm of each grade and a judgment condition which a parameter of the power change needs to satisfy are set and computation of the channel estimation algorithm selected by a highly stable grade is smaller than that of the channel estimation algorithm selected by a lowly stable grade; when estimates the channel, according to the power change situation of each time unit in current period, after the power change parameter in the current period is statistically calculated, the stability grade of the channel change in the current period is obtained by judging according to the judgment condition; then corresponding channel estimation algorithm is selected according to the stability grade so as to carry out channel estimation for the next period. The channel estimation method and the device of the invention can reduce power consumption without affecting performance.
Description
Technical field
The present invention relates to a kind of channel estimation methods and device thereof, particularly a kind of at middle channel estimation methods of CMMB (ChinaMobile Multimedia Broadcasting, China Mobile multimedia broadcasting) and device thereof.
Background technology
In the channel realization technology based on the CMMB standard, channel estimating is a wherein important step, also is a link that power consumption is very big simultaneously.In the handheld device field, power consumption is an important techniques index.
As shown in Figure 1, in the prior art about the schematic diagram of the flow processing of channel estimating.In the past channel estimating adopts single algorithm, lacks the judgement to channel status, and directly carries out computing such as subsequent communication channel estimation, causes power consumption to increase.Channel variance situation is not judged, and directly carried out channel estimating, carry out the compensation of signal, stably under the situation, still use complicated algorithm, cause the waste of power consumption at channel.
For the chip of handheld device, more satisfactory treatment state is under the channel variation complicated situation, adopts complicated channel estimation method; And, adopt simple channel estimation method at channel variation environment more stably.Therefore, how can judge the situation of channel variation, thereby determine that channel estimating adopts corresponding algorithm, avoid unnecessary power consumption consumption just to become the problem that presses for solution by channel power, noise power.
Summary of the invention
The technical problem to be solved in the present invention provides a kind of channel estimation methods and device thereof, can reduce power consumption under the situation that does not influence performance.
In order to address the above problem, the invention provides a kind of channel estimation methods, be applied to wireless communication system, this method comprises: the smoothness with variable power is divided into some ranks earlier, and the channel estimation method of each rank correspondence and the judgment condition that the variable power parameter need satisfy be set, and the channel estimation method that is the steady rank selection of height is littler than the operand of the channel estimation method of low steady rank selection, when channel estimating, variable power situation according to each chronomere in the current period, after statistics obtains the variable power parameter of whole current period, adjudicate according to described judgment condition, obtain the smoothness rank of current period channel variation; Select corresponding channel estimation method according to described smoothness rank then, next period is carried out channel estimating;
When adding up described variable power parameter, whether the power of judging each chronomere in the period successively changes, as change, then the variable power number of times is added 1, finish the variable power number of times that obtains after the judgement to all chronomeres in the period and be described variable power parameter; Then, adjudicate the smoothness rank that obtains current period channel variation according to the threshold range at this variable power number of times place again, described threshold range sets in advance;
The described period is a time slot, and described chronomere is the symbol in the time slot;
Whether the power of described symbol changes is after amplifying by the absolute value with the difference of current sign and last symbol power, as the performance number of current sign greater than or more than or equal to as described in the absolute value of difference after the amplification, the power of then judging current sign changes, otherwise judges that the power of current sign does not change.
Further, said method also can have following characteristics:
It is that it is amplified 1.5～10 times that the absolute value of described difference with current sign and last symbol power amplifies, and concrete multiplication factor is provided with according to the channel condition of reality.
Further, said method also can have following characteristics:
Described smoothness rank is divided into steadily and not steady two kinds, if the variable power number of times of the chronomere in the current period greater than or more than or equal to the threshold value of the variable power number of times of the chronomere in the default period, the smoothness rank of then adjudicating its channel variation is not for steady; Otherwise it is steady to adjudicate its channel variation.
Further, said method also can have following characteristics:
Described variable power is meant that channel power changes, or the noise power variation, or the weighted average that channel power changes and noise power changes.
Further, said method also can have following characteristics:
Described wireless communication system is the China Mobile multimedia broadcasting system.
In order to solve the problems of the technologies described above, the present invention also proposes a kind of channel estimation methods, be applied to wireless communication system, this method comprises: the smoothness with variable power is divided into some ranks earlier, and the channel estimation method of each rank correspondence and the judgment condition that the variable power parameter need satisfy be set, and the channel estimation method that is the steady rank selection of height is littler than the operand of the channel estimation method of low steady rank selection, when channel estimating, variable power situation according to each chronomere in the current period, after statistics obtains the variable power parameter of whole current period, adjudicate according to described judgment condition, obtain the smoothness rank of current period channel variation; Select corresponding channel estimation method according to described smoothness rank then, next period is carried out channel estimating;
When adding up described variable power parameter, whether the power of judging each chronomere in the period successively changes, as change, then the variable power number of times is added 1, finish the variable power number of times that obtains after the judgement to all chronomeres in the period and be described variable power parameter; Then, adjudicate the smoothness rank that obtains current period channel variation according to the threshold range at this variable power number of times place again, described threshold range sets in advance;
The described period comprises a plurality of time slots, described chronomere is the time slot that comprises a plurality of symbols, whether the power of described time slot changes is that variable power number of times according to the symbol in this time slot is judged, promptly as the variable power number of times of the symbol in this time slot greater than or more than or equal to the threshold value of the variable power number of times of the symbol in the default time slot, the power of then judging this time slot changes, otherwise judges that the power of this time slot does not change;
Whether the power of described symbol changes is after amplifying by the absolute value with the difference of current sign and last symbol power, as the performance number of current sign greater than or more than or equal to as described in the absolute value of difference after the amplification, the power of then judging current sign changes, otherwise judges that the power of current sign does not change.
Further, said method also can have following characteristics:
It is that it is amplified 1.5～10 times that the absolute value of described difference with current sign and last symbol power amplifies, and concrete multiplication factor is provided with according to the channel condition of reality.
Further, said method also can have following characteristics:
Described smoothness rank is divided into steadily and not steady two kinds, if the variable power number of times of the chronomere in the current period greater than or more than or equal to the threshold value of the variable power number of times of the chronomere in the default period, the smoothness rank of then adjudicating its channel variation is not for steady; Otherwise it is steady to adjudicate its channel variation.
Further, said method also can have following characteristics:
Described variable power is meant that channel power changes, or the noise power variation, or the weighted average that channel power changes and noise power changes.
Further, said method also can have following characteristics:
Described wireless communication system is the China Mobile multimedia broadcasting system.
In order to solve the problems of the technologies described above, the present invention also provides a kind of channel estimating apparatus, comprising: memory module, variable power statistical module, channel variation judging module and channel estimation module, wherein:
Described memory module, be used to preserve the smoothness rank of some variable power of configuration, and the channel estimation method of each rank correspondence and the variable power parameter judgment condition that need satisfy, and the operand of the channel estimation method that to be the channel estimation method selected of high steadily rank select than low steady rank is little;
Described variable power statistical module is used for the variable power situation according to each chronomere in the current period, and statistics obtains the variable power parameter of whole current period, outputs to described channel variation judging module;
Described channel variation judging module is used for adjudicating according to the variable power parameter of receiving with from the described judgment condition that described memory module is obtained, and obtains the smoothness rank of current period channel variation, outputs to described channel estimation module;
Described channel estimation module is used for selecting corresponding channel estimation method according to the described smoothness rank of receiving, next period is carried out channel estimating;
Described variable power statistical module judges successively whether the power of each chronomere in the period changes, as change, then the variable power number of times is added 1, finish the variable power number of times that obtains after the judgement to all chronomeres in the period and be described variable power parameter;
Described channel variation judging module is adjudicated the smoothness rank that obtains current period channel variation according to the threshold range at described variable power number of times place;
The data that comprise described threshold value in the judgment condition of preserving in the described memory module;
Described variable power statistical module is to be to add up a period with a time slot, when whether the power of judging described chronomere changes, is whether the power of judging the symbol in the described time slot changes;
Described variable power statistical module is when whether the power of judging symbol changes, be after amplifying by absolute value with the difference of current sign and last symbol power, as the current sign performance number greater than or more than or equal to as described in the absolute value of difference after the amplification, the power of then judging current sign changes, otherwise judges that the power of current sign does not change.
Further, said apparatus also can have following characteristics:
Described variable power statistical module is that it is amplified 1.5～10 times with the absolute value amplification of the difference of current sign and last symbol power, and concrete multiplication factor is provided with according to the channel condition of reality.
Further, said apparatus also can have following characteristics:
The smoothness rank that described memory module is preserved is divided into steadily and not steady two kinds;
Described channel variation judging module as the variable power number of times of judging the chronomere in the current period greater than or more than or equal to the threshold value of the variable power number of times of the chronomere in the default period, the smoothness rank of then adjudicating its channel variation is not for steady; Otherwise it is steady to adjudicate its channel variation.
Further, said apparatus also can have following characteristics:
Described wireless communication system is the China Mobile multimedia broadcasting system.
In order to solve the problems of the technologies described above, the present invention also provides a kind of channel estimating apparatus, comprising: memory module, variable power statistical module, channel variation judging module and channel estimation module, wherein:
Described memory module, be used to preserve the smoothness rank of some variable power of configuration, and the channel estimation method of each rank correspondence and the variable power parameter judgment condition that need satisfy, and the operand of the channel estimation method that to be the channel estimation method selected of high steadily rank select than low steady rank is little;
Described variable power statistical module is used for the variable power situation according to each chronomere in the current period, and statistics obtains the variable power parameter of whole current period, outputs to described channel variation judging module;
Described channel variation judging module is used for adjudicating according to the variable power parameter of receiving with from the described judgment condition that described memory module is obtained, and obtains the smoothness rank of current period channel variation, outputs to described channel estimation module;
Described channel estimation module is used for selecting corresponding channel estimation method according to the described smoothness rank of receiving, next period is carried out channel estimating;
Described variable power statistical module judges successively whether the power of each chronomere in the period changes, as change, then the variable power number of times is added 1, finish the variable power number of times that obtains after the judgement to all chronomeres in the period and be described variable power parameter;
Described channel variation judging module is adjudicated the smoothness rank that obtains current period channel variation according to the threshold range at described variable power number of times place;
The data that comprise described threshold value in the judgment condition of preserving in the described memory module;
Described variable power statistical module is to add up with a period that comprises a plurality of time slots, when whether the power of judging described chronomere changes, is whether the power of judging the time slot in the described period changes; And whether the power of time slot changes and judges according to the variable power number of times of the symbol in this time slot, as the variable power number of times of the symbol in this time slot greater than or more than or equal to the threshold value of the variable power number of times of the symbol in the default time slot, the power of then judging this time slot changes, otherwise judges that the power of this time slot does not change;
Described variable power statistical module is when whether the power of judging symbol changes, be after amplifying by absolute value with the difference of current sign and last symbol power, as the current sign performance number greater than or more than or equal to as described in the absolute value of difference after the amplification, the power of then judging current sign changes, otherwise judges that the power of current sign does not change.
Further, said apparatus also can have following characteristics:
Described variable power statistical module is that it is amplified 1.5～10 times with the absolute value amplification of the difference of current sign and last symbol power, and concrete multiplication factor is provided with according to the channel condition of reality.
Further, said apparatus also can have following characteristics:
The smoothness rank that described memory module is preserved is divided into steadily and not steady two kinds;
Described channel variation judging module as the variable power number of times of judging the chronomere in the current period greater than or more than or equal to the threshold value of the variable power number of times of the chronomere in the default period, the smoothness rank of then adjudicating its channel variation is not for steady; Otherwise it is steady to adjudicate its channel variation.
Further, said apparatus also can have following characteristics:
Described wireless communication system is the China Mobile multimedia broadcasting system.
Compared with prior art, the present invention is divided into some ranks by the smoothness with variable power, and after statistics obtained the variable power parameter of whole current period, judgement obtained the smoothness rank of current period channel variation, and selects corresponding channel estimation method.Because the channel estimation method that is the steady rank selection of height is littler than the operand of the channel estimation method of low steady rank selection.Therefore under the situation that does not influence performance, reduced power consumption.In addition, after the invention allows for absolute value amplification with current time unit and last chronomere power difference, compare with current time unit power value, judge the steady degree methods of channel variation with this, can the easier and result who obtains the steady degree of channel variation exactly, thus foundation provided for subsequent treatment.
Description of drawings
Fig. 1 is about the schematic diagram of the flow processing of channel estimating in the prior art;
Fig. 2 is the frame structure schematic diagram of dividing based on time slot in the prior art;
Fig. 3 among the present invention about the schematic diagram of the flow processing of channel estimating;
Fig. 4 is for carrying out the method flow diagram of channel estimating to next time slot in the embodiment of the invention;
Fig. 5 is to the following method flow diagram that carried out channel estimating in 1 second in the embodiment of the invention;
Fig. 6 is the structural representation of embodiment of the invention channel estimating apparatus.
Embodiment
The present invention further sets forth a kind of channel estimation methods of the present invention in order to solve the drawback that conventional solution exists by following specific embodiment, below embodiment is described in detail, but not as a limitation of the invention.
As shown in Figure 2, the frame structure schematic diagram for dividing based on time slot in the prior art.The physical layer signal per second is 1 frame in the CMMB standard, is divided into 40 time slots, and the length of each time slot is 25ms, comprises 1 beacon Beacon and 53 OFDM symbol symbol.
Meeting of the present invention in 1 second time according to the variable power situation of each time slot, for whether next time slot or current this 1 second next second of certain time slot in 1 second adopt the channel estimation method of simplification that basis for estimation is provided.
Basic thought is: channel power or the noise power of calculating each symbol in the current time slots, compare by the performance number of current sign and the changing value of a last symbol power, variable power situation to all symbols in the current time slots is made statistics, obtain the variable power situation of current time slots, next time slot is made estimation with this variation;
Perhaps calculate the channel power or the noise power of each symbol in the current time slots, compare by the performance number of current sign and the changing value of a last symbol power, variable power situation to all symbols in the current time slots is made statistics, obtain the variable power situation of current time slots, obtain the variable power situation of each time slot in 1 second again by same method, statistics obtains variable power situation total in 1 second, with this variable power situation to making estimation in following 1 second.
Below be the object of channel estimating with the time slot in 1 second, according to the method for present embodiment, provide basis for estimation to the channel estimation method of next time slot of current time slots.
As shown in Figure 3, for among the present invention about the schematic diagram of the flow processing of channel estimating, compare with prior art shown in Figure 1, increase feedback in the frame of broken lines, judge, and the step of algorithm switching, output result according to the current time slots channel estimating judges channel situation, and situation about judging is fed back to the channel estimating part, and channel estimating can be selected suitable algorithm in view of the above.
Below the step in the frame of broken lines among Fig. 3 is described in detail.With a time slot in 1 second is example, the variable power situation of this time slot in this 1 second is judged, thereby the foundation of selection is provided for the channel estimation method of next time slot.
As shown in Figure 4, for next time slot in the embodiment of the invention carries out the method flow diagram of channel estimating, may further comprise the steps:
Step 400, the power of each OFDM symbol in the calculating current time slots;
Step 401, the variable power situation and the record of each symbol and previous symbol in the judgement current time slots;
Calculate the absolute value of the difference of current OFDM symbol and previous OFDM symbol power, and with this absolute value be amplified to the same magnitude of current OFDM symbol power on compare; If current OFDM symbol power value is bigger, think that then current OFDM symbol power changes greatly, adds 1 with change frequency; Judge the variable power of next OFDM symbol then, record change frequency, all the OFDM symbols in complete time slot of statistics.
Here the absolute value of described difference can be amplified 1.5～10 times, as adopting 2～4 times, concrete multiplication factor can be adjusted according to the channel condition of reality.
Step 402 counts the variable power situation of whole time slot;
Add up all the OFDM symbols in complete the time slot, obtain a total variable power number of times, describe out the variable power situation of whole time slot with described variable power number of times;
Step 403 according to the variable power situation of current time slots, judges whether the current time slots channel changes steadily;
The variable power number of times is set a threshold value,, represent that its channel variation can be bigger if the total variable power number of times of current time slots has surpassed this threshold value; If the total variable power number of times of current time slots does not surpass this threshold value, represent that then its channel changes steadily relatively;
Step 404 according to the situation of change of the current time slots channel of judging, is selected respective algorithms, and next time slot is carried out channel estimating;
In the channel variation of current time slots more stably the time, under the situation that does not influence the channel-decoding performance, the channel estimating of next time slot is adopted relatively more conservative algorithm, all valid data of next time slot are carried out channel estimating obtain channel model;
When the channel variation of current time slots is bigger, need adopt accurate algorithm to guarantee the channel-decoding performance to the channel estimating of next time slot.
The algorithm operation quantity of selecting when the algorithm of selecting when above-mentioned channel variation is relatively more steady is bigger than channel variation is little.Thereby can under the prerequisite that does not influence channel estimating performance, save power consumption.
Application example is as follows:
1) power of each symbol in the calculating current time slots can selective channel power or noise power.
No matter selective channel power, or noise power all need be carried out by step of the present invention; both only differences to some extent on algorithm; and the algorithm at channel power and noise power is varied in this area, and is also known by those skilled in the art, protection of the present invention is not produced to limit.So following description is an example with a kind of channel power algorithm only, also can do similar processing for noise power, just repeats no more.
1i) calculate the significant figure strong point real part in the OFDM symbol and the quadratic sum of imaginary part, obtain the power at this significant figure strong point:
Hf[i]＝symbol_i[i]×symbol_i[i]+symbol_q[i]×symbol_q[i]；
Wherein, symbol_i[i]: the real part at the significant figure strong point in OFDM symbol;
Symbol_q[i]: the imaginary part at the significant figure strong point in OFDM symbol;
1ii), obtain this OFDM symbol performance number with 2610 valid data summations:
Wherein, Es: this OFDM symbol (comprising 2610 significant figure strong points) power;
1iii) channel power of trying to achieve is revised, is obtained revised this OFDM symbol performance number:
Es＝(Es＞＞2)+(Es＞＞3)+(Es＞＞6)-(Es＜＜10)
2) judge variable power between the symbol, and count the variable power situation of whole time slot
2i) calculate the absolute value diff_power of the difference of current OFDM symbol and previous OFDM symbol power, and with this absolute value be amplified to the same magnitude of current OFDM symbol power on, to guarantee and can compare;
diff_power＝|Es[i]-Es[i-1]|＜＜2
Here be that absolute value with described difference moves to left two and promptly amplifies 4 times, but this multiplication factor can dispose according to actual channel conditions, can be provided with according to statistics.
2ii) as step 2i) in whenever obtain a power difference diff_power after, with regard to current OFDM symbol power Es[i] and top power difference diff_power once compare, if performance number Es[i] bigger, think that then current OFDM symbol power changes greatly, and the record change frequency adds 1;
if(Es[i]＞diff_power)
diff_cnt＝diff_cnt+1；
After finishing the statistics of this variable power, go back to step 2i), switch to next OFDM symbol as current OFDM symbol, carry out the calculating of the difference of channel power with an OFDM symbol before this symbol, and then execution in step 2ii) judgement in adds up, circulation is carried out, and all the OFDM symbols in complete time slot of statistics obtain a total variable power number of times diff_cnt.
Because comprise 53 OFDM symbols in each time slot, therefore, step 2i) in, i gets 1 to 52.
3) channel variance situation of judgement current time slots.
The variable power number of times is set a threshold value, if the total variable power number of times diff_cnt of current time slots has surpassed this threshold value, the OFDM symbol power in the expression current time slots changes greatly, and its channel variation is bigger; If the total variable power number of times diff_cnt of current time slots does not surpass this threshold value, represent that then the OFDM symbol power in the current time slots changes not quite, its channel changes steadily relatively.
For choosing of threshold value, can select 6 in practice, when these data are smaller, judge relatively more responsive; Bigger threshold value is set can cause accuracy to descend.
4) according to the channel variance situation of current time slots, for next time slot carries out channel estimating, as whether adopting the foundation that algorithm provided of saving power.
In the channel variation of current time slots more stably the time, under the situation that does not influence the channel-decoding performance, the channel estimating of next time slot is adopted relatively more conservative way, reach the purpose of saving power;
When the channel variation of current time slots is bigger, need adopt accurate algorithm to guarantee the channel-decoding performance to the channel estimating of next time slot.
In addition, the present invention can be used for adding up a symbol power situation of change in the time slot, also can add up the variable power situation of (quantity can be determined according to actual conditions) in a plurality of time slots.By adding up the variable power situation in a plurality of time slots, just can obtain the variable power situation in 1 second, thereby select following 1 second channel estimating.
As shown in Figure 5, below with 1 second be the object of channel estimating, the method according to this invention provides basis for estimation to following 1 second channel estimation method:
Step 500 can obtain the situation of change of current time slots by top embodiment, and is stable or change bigger; Set a variable power number of times in 1 second, if the variation of current time slots is bigger, then change frequency adds 1;
Then to next time slot, carry out as the step of top embodiment, judge the situation of change of next time slot, stable or change greatlyyer, the same number of pass times in addition record that adds up is until having added up all time slots in 1 second;
In the CMMB standard in the physical layer signal, be divided into 40 time slots in 1 second, for above-mentioned steps 500, in actual applications, can be not 40 time slots in this 1 second not all be judged statistics, may only select wherein several slots immediately and add up,, describe the variable power situation in whole 1 second with the variable power situation of this several slots that counts;
And for the judgement of the variable power situation of each time slot, can be according to the method for the described embodiment of Fig. 4, obtain by statistics the variable power situation of the symbol in the time slot, also might obtain by additive method.About the selection of herein embodiment, not as a limitation of the invention.
After in step 500, obtaining the variable power situation of each time slot in 1 second, the statistics and the judgement of this 1 second variable power situation after carrying out according to step of the present invention again, and the channel estimating of next second:
Step 501 is set a threshold value to the variable power number of times in 1 second, if total variable power number of times is bigger than this threshold value in 1 second, represents that the variable power of the time slot in this 1 second is bigger, and its channel variation is bigger; If variable power number of times total in this 1 second does not surpass this threshold value, represent that then the variable power of the time slot in this 1 second is little, its channel changes steadily relatively;
Step 502, the channel variation in this 1 second be more stably the time, under the situation that does not influence the channel-decoding performance, the channel estimating of next second adopted relatively more conservative way, reaches the purpose of saving power;
When the channel variation in this 1 second is bigger, need adopt accurate algorithm to guarantee the channel-decoding performance to the channel estimating of next second.
In addition, arbitrarily duration all can be according to the method described in the present invention, with reference to 1 second treatment step, expands, and operates identically, repeats no more.
As shown in Figure 6, be the structural representation of present embodiment channel estimating apparatus.Comprise: memory module, variable power statistical module, channel variation judging module and channel estimation module, wherein:
Memory module 1, be used to preserve the smoothness rank of some variable power of configuration, and the channel estimation method of each rank correspondence and stipulated the judgment condition of the threshold condition that the variable power parameter need satisfy, and be that the channel estimation method selected of high steadily rank is littler than the operand of the channel estimation method of low steady rank selection.The smoothness rank that described memory module is preserved can be divided into steadily and not steady two kinds.
Variable power statistical module 2 is used for the variable power situation according to each chronomere in the current period, and statistics obtains the variable power parameter of whole current period, outputs to described channel variation judging module.Particularly, whether the power that can judge each chronomere in the period successively changes, as change, then the variable power number of times is added 1, finish the variable power number of times that obtains after the judgement to all chronomeres in the period and be described variable power parameter.
Corresponding to two kinds of execution modes in the method, the variable power statistical module can be to add up a period with a time slot, when whether the power of judging described chronomere changes, is whether the power of judging the symbol in the described time slot changes.Perhaps, the variable power statistical module also can be added up with a period that comprises a plurality of time slots, when whether the power of judging described chronomere changes, is whether the power of judging the time slot in the described period changes; And whether the power of time slot changes and judges according to the variable power number of times of the symbol in this time slot, as the variable power number of times of the symbol in this time slot greater than or more than or equal to default respective threshold, the power of then judging this time slot changes, otherwise judges that the power of this time slot does not change.And when whether the power of judging symbol changes, can be amplified to by absolute value the difference of current sign and last symbol power with the same magnitude of current sign performance number after, as the current sign performance number greater than or more than or equal to as described in the absolute value of difference after the amplification, the power of then judging current sign changes, otherwise judges that the power of current sign does not change.
Channel variation judging module 3 is used for adjudicating according to the variable power parameter of receiving with from the described judgment condition that described memory module is obtained, and obtains the smoothness rank of current period channel variation, outputs to described channel estimation module.Particularly, can adjudicate the smoothness rank that obtains current period channel variation according to the threshold range at described variable power number of times place.When the smoothness rank is divided into steadily with not steady two kinds, described channel variation judging module as the variable power number of times of judging the chronomere in the current period greater than or more than or equal to default respective threshold, the smoothness rank of then adjudicating its channel variation is not for steady; Otherwise it is steady to adjudicate its channel variation.
Channel estimation module 4 is used for selecting corresponding channel estimation method according to the described smoothness rank of receiving, next period is carried out channel estimating.
Certainly; the present invention also can have other various embodiments; under the situation that does not deviate from spirit of the present invention and essence thereof; those of ordinary skill in the art can make various corresponding changes and distortion according to the present invention, but these corresponding changes and distortion all should belong to the protection range of the appended claim of the present invention.
For example, be that the steady degree of channel variation is divided into two ranks in the foregoing description, promptly steadily with not steady, but also can be divided into more rank in other embodiments, as 3, each rank is selected a channel estimation method, can select the little algorithm of operand in the high steady rank.
Claims (18)
1. channel estimation methods, be applied to wireless communication system, it is characterized in that, smoothness with variable power is divided into some ranks earlier, and the channel estimation method of each rank correspondence and the judgment condition that the variable power parameter need satisfy be set, and the channel estimation method that is the steady rank selection of height is littler than the operand of the channel estimation method of low steady rank selection, when channel estimating, variable power situation according to each chronomere in the current period, after statistics obtains the variable power parameter of whole current period, adjudicate according to described judgment condition, obtain the smoothness rank of current period channel variation; Select corresponding channel estimation method according to described smoothness rank then, next period is carried out channel estimating;
When adding up described variable power parameter, whether the power of judging each chronomere in the period successively changes, as change, then the variable power number of times is added 1, finish the variable power number of times that obtains after the judgement to all chronomeres in the period and be described variable power parameter; Then, adjudicate the smoothness rank that obtains current period channel variation according to the threshold range at this variable power number of times place again, described threshold range sets in advance;
The described period is a time slot, and described chronomere is the symbol in the time slot;
Whether the power of described symbol changes is after amplifying by the absolute value with the difference of current sign and last symbol power, as the performance number of current sign greater than or more than or equal to as described in the absolute value of difference after the amplification, the power of then judging current sign changes, otherwise judges that the power of current sign does not change.
2. the method for claim 1 is characterized in that,
It is that it is amplified 1.5～10 times that the absolute value of described difference with current sign and last symbol power amplifies, and concrete multiplication factor is provided with according to the channel condition of reality.
3. the method for claim 1 is characterized in that,
Described smoothness rank is divided into steadily and not steady two kinds, if the variable power number of times of the chronomere in the current period greater than or more than or equal to the threshold value of the variable power number of times of the chronomere in the default period, the smoothness rank of then adjudicating its channel variation is not for steady; Otherwise it is steady to adjudicate its channel variation.
4. the method for claim 1 is characterized in that,
Described variable power is meant that channel power changes, or the noise power variation, or the weighted average that channel power changes and noise power changes.
5. the method for claim 1 is characterized in that, described wireless communication system is the China Mobile multimedia broadcasting system.
6. channel estimation methods, be applied to wireless communication system, it is characterized in that, smoothness with variable power is divided into some ranks earlier, and the channel estimation method of each rank correspondence and the judgment condition that the variable power parameter need satisfy be set, and the channel estimation method that is the steady rank selection of height is littler than the operand of the channel estimation method of low steady rank selection, when channel estimating, variable power situation according to each chronomere in the current period, after statistics obtains the variable power parameter of whole current period, adjudicate according to described judgment condition, obtain the smoothness rank of current period channel variation; Select corresponding channel estimation method according to described smoothness rank then, next period is carried out channel estimating;
When adding up described variable power parameter, whether the power of judging each chronomere in the period successively changes, as change, then the variable power number of times is added 1, finish the variable power number of times that obtains after the judgement to all chronomeres in the period and be described variable power parameter; Then, adjudicate the smoothness rank that obtains current period channel variation according to the threshold range at this variable power number of times place again, described threshold range sets in advance;
The described period comprises a plurality of time slots, described chronomere is the time slot that comprises a plurality of symbols, whether the power of described time slot changes is that variable power number of times according to the symbol in this time slot is judged, promptly as the variable power number of times of the symbol in this time slot greater than or more than or equal to the threshold value of the variable power number of times of the symbol in the default time slot, the power of then judging this time slot changes, otherwise judges that the power of this time slot does not change;
Whether the power of described symbol changes is after amplifying by the absolute value with the difference of current sign and last symbol power, as the performance number of current sign greater than or more than or equal to as described in the absolute value of difference after the amplification, the power of then judging current sign changes, otherwise judges that the power of current sign does not change.
7. method as claimed in claim 6 is characterized in that,
It is that it is amplified 1.5～10 times that the absolute value of described difference with current sign and last symbol power amplifies, and concrete multiplication factor is provided with according to the channel condition of reality.
8. method as claimed in claim 6 is characterized in that,
Described smoothness rank is divided into steadily and not steady two kinds, if the variable power number of times of the chronomere in the current period greater than or more than or equal to the threshold value of the variable power number of times of the chronomere in the default period, the smoothness rank of then adjudicating its channel variation is not for steady; Otherwise it is steady to adjudicate its channel variation.
9. method as claimed in claim 6 is characterized in that,
Described variable power is meant that channel power changes, or the noise power variation, or the weighted average that channel power changes and noise power changes.
10. method as claimed in claim 6 is characterized in that, described wireless communication system is the China Mobile multimedia broadcasting system.
11. a channel estimating apparatus is characterized in that, comprising: memory module, variable power statistical module, channel variation judging module and channel estimation module, wherein:
Described memory module, be used to preserve the smoothness rank of some variable power of configuration, and the channel estimation method of each rank correspondence and the variable power parameter judgment condition that need satisfy, and the operand of the channel estimation method that to be the channel estimation method selected of high steadily rank select than low steady rank is little;
Described variable power statistical module is used for the variable power situation according to each chronomere in the current period, and statistics obtains the variable power parameter of whole current period, outputs to described channel variation judging module;
Described channel variation judging module is used for adjudicating according to the variable power parameter of receiving with from the described judgment condition that described memory module is obtained, and obtains the smoothness rank of current period channel variation, outputs to described channel estimation module;
Described channel estimation module is used for selecting corresponding channel estimation method according to the described smoothness rank of receiving, next period is carried out channel estimating;
Described variable power statistical module judges successively whether the power of each chronomere in the period changes, as change, then the variable power number of times is added 1, finish the variable power number of times that obtains after the judgement to all chronomeres in the period and be described variable power parameter;
Described channel variation judging module is adjudicated the smoothness rank that obtains current period channel variation according to the threshold range at described variable power number of times place;
The data that comprise described threshold value in the judgment condition of preserving in the described memory module;
Described variable power statistical module is to be to add up a period with a time slot, when whether the power of judging described chronomere changes, is whether the power of judging the symbol in the described time slot changes;
Described variable power statistical module is when whether the power of judging symbol changes, be after amplifying by absolute value with the difference of current sign and last symbol power, as the current sign performance number greater than or more than or equal to as described in the absolute value of difference after the amplification, the power of then judging current sign changes, otherwise judges that the power of current sign does not change.
12. device as claimed in claim 11 is characterized in that,
Described variable power statistical module is that it is amplified 1.5～10 times with the absolute value amplification of the difference of current sign and last symbol power, and concrete multiplication factor is provided with according to the channel condition of reality.
13. device as claimed in claim 11 is characterized in that,
The smoothness rank that described memory module is preserved is divided into steadily and not steady two kinds;
Described channel variation judging module as the variable power number of times of judging the chronomere in the current period greater than or more than or equal to the threshold value of the variable power number of times of the chronomere in the default period, the smoothness rank of then adjudicating its channel variation is not for steady; Otherwise it is steady to adjudicate its channel variation.
14. device as claimed in claim 11 is characterized in that, described wireless communication system is the China Mobile multimedia broadcasting system.
15. a channel estimating apparatus is characterized in that, comprising: memory module, variable power statistical module, channel variation judging module and channel estimation module, wherein:
Described memory module, be used to preserve the smoothness rank of some variable power of configuration, and the channel estimation method of each rank correspondence and the variable power parameter judgment condition that need satisfy, and the operand of the channel estimation method that to be the channel estimation method selected of high steadily rank select than low steady rank is little;
Described variable power statistical module is used for the variable power situation according to each chronomere in the current period, and statistics obtains the variable power parameter of whole current period, outputs to described channel variation judging module;
Described channel variation judging module is used for adjudicating according to the variable power parameter of receiving with from the described judgment condition that described memory module is obtained, and obtains the smoothness rank of current period channel variation, outputs to described channel estimation module;
Described channel estimation module is used for selecting corresponding channel estimation method according to the described smoothness rank of receiving, next period is carried out channel estimating;
Described variable power statistical module judges successively whether the power of each chronomere in the period changes, as change, then the variable power number of times is added 1, finish the variable power number of times that obtains after the judgement to all chronomeres in the period and be described variable power parameter;
Described channel variation judging module is adjudicated the smoothness rank that obtains current period channel variation according to the threshold range at described variable power number of times place;
The data that comprise described threshold value in the judgment condition of preserving in the described memory module;
Described variable power statistical module is to add up with a period that comprises a plurality of time slots, when whether the power of judging described chronomere changes, is whether the power of judging the time slot in the described period changes; And whether the power of time slot changes and judges according to the variable power number of times of the symbol in this time slot, as the variable power number of times of the symbol in this time slot greater than or more than or equal to the threshold value of the variable power number of times of the symbol in the default time slot, the power of then judging this time slot changes, otherwise judges that the power of this time slot does not change;
Described variable power statistical module is when whether the power of judging symbol changes, be after amplifying by absolute value with the difference of current sign and last symbol power, as the current sign performance number greater than or more than or equal to as described in the absolute value of difference after the amplification, the power of then judging current sign changes, otherwise judges that the power of current sign does not change.
16. device as claimed in claim 15 is characterized in that,
Described variable power statistical module is that it is amplified 1.5～10 times with the absolute value amplification of the difference of current sign and last symbol power, and concrete multiplication factor is provided with according to the channel condition of reality.
17. device as claimed in claim 15 is characterized in that,
The smoothness rank that described memory module is preserved is divided into steadily and not steady two kinds;
Described channel variation judging module as the variable power number of times of judging the chronomere in the current period greater than or more than or equal to the threshold value of the variable power number of times of the chronomere in the default period, the smoothness rank of then adjudicating its channel variation is not for steady; Otherwise it is steady to adjudicate its channel variation.
18. device as claimed in claim 15 is characterized in that, described wireless communication system is the China Mobile multimedia broadcasting system.
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| CN1677908A (en) * | 2004-03-31 | 2005-10-05 | 清华大学 | TDS-OFDM receiver self-adaptive channel estimation balancing method and system |
| WO2007108789A1 (en) * | 2006-03-17 | 2007-09-27 | Nokia, Inc. | Reduced power consumption in software radios |
| CN101394196A (en) * | 2007-09-20 | 2009-03-25 | 北京信威通信技术股份有限公司 | Dynamically regulating method and device for frame structure in channel estimation |
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| WO2007108789A1 (en) * | 2006-03-17 | 2007-09-27 | Nokia, Inc. | Reduced power consumption in software radios |
| CN101394196A (en) * | 2007-09-20 | 2009-03-25 | 北京信威通信技术股份有限公司 | Dynamically regulating method and device for frame structure in channel estimation |
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