CN101217343B - A smooth regulation method on type of modulation - Google Patents
A smooth regulation method on type of modulation Download PDFInfo
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- CN101217343B CN101217343B CN2008100558722A CN200810055872A CN101217343B CN 101217343 B CN101217343 B CN 101217343B CN 2008100558722 A CN2008100558722 A CN 2008100558722A CN 200810055872 A CN200810055872 A CN 200810055872A CN 101217343 B CN101217343 B CN 101217343B
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Abstract
The invention discloses a method for implementing a modulating way with smooth adjustment, and in a communication system of orthogonal frequency division multiple access (OFDMA), sampling and statistics are carried out for the uplink signal-to-noise rate (ULSNR) and the downlink signal-to-noise rate (DLSNR) of a wireless channel periodically, the degree of the modulating way of the communication system are dynamically adjusted according to the statistics result, when the ULSNR and the DLSNR satisfy rate conditions of the modulating way with certain degree, the modulating way of each channel carrier is adjusted, thus effectively solving the influence of the modulating way mutation on system stability which is caused by the mutation of channel conditions, ensuring smooth data transmission, and improving the degree of satisfaction of users.
Description
Technical field
The present invention relates to the channel modulation techniques of OFDM (OFDMA) system, relate in particular to a kind of method of level and smooth adjustment modulation system.
Background technology
OFDM (OFDM) technology is disturbed and the spectrum efficiency advantages of higher anti-multipath owing to it possesses effectively, develops into one of mainstream technology of wireless communication field in recent years gradually.The OFDM technology has been widely used in audio frequency, video field and the commercial signal communication system of broadcast type at present, and main application comprises: the digital audio broadcasting (DAB) of asymmetrical Digital Subscriber Loop (ADSL), etsi standard, digital video broadcasting (DVB), high definition TV (HDTV), wireless lan (wlan) etc.OFDMA is as a kind of form of OFDM modulation, and as the expansion of OFDM technology, it is optimized at multi-user communication simultaneously, especially mobile communication system and other mobile communication equipment is optimized.Current, employing OFDMA technology is the strong competitor that World Interoperability for Microwave Access, WiMax (WiMAX) system of physical layer core technology has become the next generation mobile communication technical standard.
Multiple-input, multiple-output (MIMO) technology is one of wireless mobile communications field intelligent antenna technology, this technology can improve the capability of communication system and the availability of frequency spectrum exponentially under the situation that does not increase bandwidth, therefore become the key technology that the third generation mobile communication system must adopt.The OFDMA+MIMO technology is compared with code division multiple access (CDMA) technology of 3-G (Generation Three mobile communication system), have technical advantages such as the higher availability of frequency spectrum, better transmission channel anti fading performance, therefore, the OFDMA+MIMO technology is more suitable for wide-band mobile communication system, thereby is acknowledged as one of core technology of next generation mobile communication system.
But, using the OFDMA technology carries out in the modulated process carrier signal, when undergoing mutation, the signal to noise ratio (snr) in the OFDMA system causes the sudden change of modulation system easily, particularly portable terminal requires to be in situation in the rapid movement again than higher and portable terminal to transmission bandwidth, because channel circumstance changes the frequency height, therefore in the very short a bit of time, the fluctuation of signal also can be very big.For example, when transmission signals has a bigger pulse or decline to change in moment, if adjust modulation system according to moment SNR value this moment, then may cause and select modulation system higher-order or lower-order irrelevantly, but because channel is to keep this situation moment, and the feedback of channel conditions is periodic, need wait next time to give the correct time on the channel situation and just can carry out if will redefine modulation system, and the transmission error code phenomenon will occur or influence data throughout this moment.
Signal level schematic diagram when Fig. 1 undergos mutation for SNR, as shown in the figure, reflected that portable terminal is in the process of fast moving, portable terminal enters in the zone of a sighting distance, very good at this channel condition constantly, this moment, signal level was higher, but owing to path loss or after entering the non line of sight zone, channel is decline at once, signal level this moment step-down thereupon.This situation will follow the rapid movement of portable terminal to occur repeatedly.
Mobile terminal data throughput schematic diagram when Fig. 2 undergos mutation for SNR, as shown in the figure, if determined the modulation system of a high-order preferably constantly at channel, when channel declines suddenly, the exponent number of modulation system is forced to again descend, frequent adjustment can cause system's instability, and this moment, crenellated phenomena appearred in terminal data throughput of transmissions easily.This mainly is because SNR when undergoing mutation, and signal can't proper solution have regulated and guided certain transfer of data and error code occurred, and the further result of deterioration.
Therefore, in real time modulation system is carried out frequent adjustment if change according to the fluctuation of signal, will cause the instability of modulation system, this will inevitably cause the instability of whole OFDMA system.Particularly for the mobility of portable terminal and the very high WiMAX system of requirement of bandwidth, the fast moving of portable terminal must be brought the quick variation of the modulated signal in the channel, but this variation of signal is again temporary transient probably, this is transmission channel circumstance complication regional particularly evident aloft, just becomes WiMAX system problem demanding prompt solution so how to guarantee the stability of mobile terminal data throughput of transmissions under the situation of sign mutation.
Summary of the invention
In view of this, main purpose of the present invention is to provide a kind of self-adaptation control method of level and smooth adjustment modulation system, improves the stability of communication system modulated process and guarantees seamlessly transitting of message transmission rate, improves user's satisfaction.
For achieving the above object, technical scheme of the present invention is achieved in that
A kind of method of level and smooth adjustment modulation system, this method comprises:
A, gather the signal to noise ratio snr information of channel, and the measurement period of valid frame under the different rank modulation system is set;
B, judge whether the available frame count in the current measurement period reaches statistical condition, with the available frame count statistics zero clearing of current measurement period, and do not return step a when reaching statistical condition;
C, calculate current rising ratio or current decreasing ratio according to the available frame count in the measurement period, and respectively with the different rank modulation system of prior setting under rising ratio threshold value or decreasing ratio threshold value compare, if satisfy the exponent number regularization condition, then heighten or reduce the exponent number of modulation system; Otherwise the exponent number of keeping current modulation mode is constant.
Wherein, the described modulation system of step a comprises at least: binary phase shift keying BPSK, four phase absolute phase shift keying QPSK, eight phase absolute phase shift keying 8PSK, 16 attitude quadrature amplitude modulation 16QAM, 64 attitude quadrature amplitude modulation 64QAM and 128 attitude quadrature amplitude modulation 128QAM.
The SNR information of the described collection channel of step a is specially: gather up signal to noise ratio ULSNR and descending signal to noise ratio DLSNR.
The SNR information of the described collection channel of step a is specially: the base station physical layer measures the ULSNR value and reports the MAC layer as SNR information; And the physical layer of terminal measures DLSNR and reports self MAC layer, by the MAC layer DLSNR formed upstream message and passes to the physical layer of self, is sent to the base station by eating dishes without rice or wine as ULSNR information.
The mode of the SNR information of the described collection channel of step a is specially: adopt the SNR of the mode match exponents rising modulation system of stationary window to add up, adopt the SNR of the mode match exponents reduction modulation system of sliding window to add up.
The described measurement period that is provided with of step a is specially: for the measurement period under the exponent number rising situation, periodic quantity is 1～200 frame; For the measurement period under the exponent number reduction situation, periodic quantity fixedly is changed to 1 frame.
Step a further comprises: the SNR information of being gathered is kept at rises in rank statistics array or the depression of order statistics array.
Step a further comprises: determine cycle frame number and corresponding available frame count standard under the different rank modulation system.
Step b is described to judge that whether the available frame count in the current measurement period reaches statistical condition, is specially: judge that whether the interior available frame count of measurement period is greater than the available frame count standard.
Available frame count in the described counting statistics cycle of step c is specially: by traversing operation, the available frame count that rises in rank statistics array or the depression of order statistics array is come out.
Step c is described to be judged whether to comprise the exponent number that satisfies the exponent number regularization condition and whether adjust modulation system:
C1, the pairing rising ratio of the modulation system threshold value RiseRatio of different rank is set
FixedAnd decreasing ratio threshold value DropRatio
Fixed, and, calculate current rising ratio R iseRatio according to the statistics of available frame count
CurrentOr current decreasing ratio DropRatio
Current, execution in step c2 or c4 then;
C2, with current rising ratio R iseRatio
CurrentWith RiseRatio
FixedCompare, if current rising ratio is greater than rising ratio threshold value, then execution in step c3; Otherwise, execution in step c6;
C3, heighten the exponent number of current modulation mode, finish the processing procedure of this measurement period, enter next measurement period;
C4, with current decreasing ratio DropRatio
CurrentWith DropRatio
FixedCompare, if current decreasing ratio is greater than the decreasing ratio threshold value, execution in step c5 then; Otherwise, execution in step c6;
C5, reduce the exponent number of current modulation mode, finish the processing procedure of this measurement period, enter next measurement period;
C6, the exponent number of keeping current modulation mode are constant, finish the processing procedure of this measurement period, enter next measurement period.
Wherein, the described mode of heightening the exponent number of current modulation mode of step c3 is specially: the mode of mode of Shang Shenging or multistage rising step by step.
The mode of the exponent number of the described reduction current modulation mode of step c5 is specially: the mode of mode of Xia Jianging or multistage decline step by step.
The self-adaptation control method of level and smooth adjustment modulation system provided by the present invention has the following advantages:
1) the present invention judges by periodically the SNR that is gathered being carried out validity, prevented that the channel instantaneous mutation from causing the adverse effect that modulation system frequently changes thereupon, make the adjustment of modulation system between different rank play cushioning effect, thereby improved portable terminal transfer of data stable in the high-speed motion process.
2) by gatherer process different working methods is set among the present invention to SNR, adopt the sliding window mode when promptly the Channel Transmission condition being adopted when better stationary window mode and Channel Transmission condition relatively poor, the kind mode can improve the exponent number of modulation system rapidly before using, and the transmission rate of channel is got a promotion as far as possible; Use a kind of mode in back, play the effect of stablize the modulation system exponent number, thereby keep stablizing of transfer of data under the current modulation mode as much as possible.
3) the present invention is according to the difference of modulation system exponent number, be provided with the rising ratio threshold value and the decreasing ratio threshold value of different sizes, by contrasting with current rising ratio or with current decreasing ratio, select step by step/multistage rising, or step by step/mode of multistage decline, improve the multiple choices scheme of the exponent number adjustment of different channels situation modulated mode, improved the adaptability of the inventive method.
Description of drawings
Signal level schematic diagram when Fig. 1 undergos mutation for SNR;
Mobile terminal data throughput schematic diagram when Fig. 2 undergos mutation for SNR;
Fig. 3 is a stationary window data acquisition modes schematic diagram in the embodiment of the invention;
Fig. 4 is a sliding window data acquisition mode schematic diagram in the embodiment of the invention;
Fig. 5 is a statistics and judging process flow chart in the embodiment of the invention;
Fig. 6 is that the modulation system exponent number raises and the situation of reduction schematic diagram in the embodiment of the invention;
Fig. 7 is the process flow diagram that the modulation system exponent number is adjusted in the embodiment of the invention.
Embodiment
Below in conjunction with accompanying drawing and embodiments of the invention method of the present invention is described in further detail.
Basic thought of the present invention is: by periodically the up signal to noise ratio (ULSNR) of wireless transmission channel, descending signal to noise ratio (ULSNR) being gathered and added up, and the exponent number of the modulation system of communication system is dynamically adjusted according to statistics, when ULSNR and DLSNR satisfy the condition of certain ratio, adjust the modulation system of each self-channel, thereby the realization modulation system can be adjusted in real time according to the variation of channel.
Under the wireless channel environment, the modulation system that communication system adopted directly determines the quality of the height and the communication quality of the error rate, particularly when the exponent number of modulation system is adjusted, communication system is relatively tolerant for the modulation system of low order, because can remedy the channel conditions deteriorate adverse effect by the mode of sacrificing bandwidth; And for the heightening of the exponent number of higher order modulation schemes, then should be very prudent, because under unsettled channel circumstance, use the modulation system of high-order can cause the bigger error rate, when serious even cause portable terminal to break away from network.The modulation system that is adopted in the embodiment of the invention, be arranged in order from low to high according to exponent number, include at least: binary phase shift keying (BPSK), four phase absolute phase shift keyings (QPSK), eight phase absolute phase shift keyings (8PSK), 16 attitude quadrature amplitude modulation (16QAM), 64 attitude quadrature amplitude modulation (64QAM) and 128 attitude quadrature amplitude modulation modulation systems such as (128QAM).When channel circumstance is the poorest, adopt the BPSK modulation system; When channel circumstance is optimum, select the modulation system of high-order as much as possible, as: 64QAM, 128QAM even the modulation system of high-order more.
In actual wireless communication, channel situation is a real-time change, and adopting high-order still is that the low-order-modulated mode is modulated carrier signal, need decide according to the good and bad situation of channel.Usually be the adjustment that index is carried out corresponding modulation system with the signal to noise ratio (snr) of gathering channel, SNR is divided into up signal to noise ratio (ULSNR) and descending signal to noise ratio (DLSNR) by the difference of Channel Transmission direction.The collection of parameter ULSNR can be measured by the baseband processing module by the base station physical layer, and measurement result is reported media interviews controls (MAC) layer further handles; For the collection of parameter DLSNR relative complex then, because according to the IEEE802.16e agreement, need the physical layer of portable terminal to measure DLSNR and report self MAC layer, by the MAC layer DLSNR is formed upstream message again and pass to the physical layer of self, be sent to the base station by air interface then and be further processed again.
The present invention adds up the SNR situation of every frame within certain frame number scope of transmission channel, this frame number scope is called as measurement period, be also referred to as statistical window, according to actual needs, the big I of statistical window value is selected arbitrarily within 1～200 frame, and the value of statistical window also can in use dynamically be adjusted, to satisfy the requirement of adjusting the communication system response speed according to the change dynamics of SNR.For example, the as if statistics window is the length of 6 frames in the embodiment of the invention.According to the working method of statistical window, be divided into two kinds of stationary window mode and sliding window modes, below introduce it respectively.
Fig. 3 is a stationary window data acquisition modes schematic diagram in the embodiment of the invention, as shown in Figure 3, when the situation of statistics SNR, is that step-length is in turn added up the SNR information in the statistical window and reported with the periodic quantity, and this mode is called the stationary window mode.
Fig. 4 is a sliding window data acquisition mode schematic diagram in the embodiment of the invention, as shown in Figure 4, when the situation of statistics SNR, be that step-length is added up the SNR information in the statistical window slidably and reported with single frame length, this statistical is called the sliding window mode.
The variation tendency of the exponent number of modulation system has two kinds, promptly raises or reduction., should consider the exponent number of modulation system is improved, preferably under the situation for channel condition to improve the transmission rate of channel; For the relatively poor situation of channel condition, just should consider to reduce the exponent number of modulation system, but should not reduce exponent number immediately, keeping stability of data transmission, the moment SNR value when avoiding channel circumstance to undergo mutation is to influence that communication system caused.
Therefore, when channel conditions improved when the exponent number of modulation system had the rising potentiality, system adds up the situation of SNR, need to adopt periodic statistical, periodic quantity also can dynamically be adjusted according to actual conditions, to change communication system, obtain SNR information and correspondingly should adopt as shown in Figure 3 stationary window mode the response speed that SNR changes.
SNR situation in the time of need reducing for the modulation system exponent number during channel conditions deteriorate is added up, also adopt periodic statistical, but periodic quantity is fixed as 1 frame, promptly the SNR to every frame all adds up, can grasp the situation of channel variation in real time with the assurance system, and in time the exponent number of modulation system is adjusted, obtain SNR information this moment and then correspondingly adopt as shown in Figure 4 sliding window mode.
The front was mentioned, and can measure by the physical layer baseband processing module for ULSNR in the wireless channel environment, but DLSNR needed portable terminal to report by up channel.Under the actual conditions, comprise ULSNR and DLSNR, can not guarantee that the SNR information of every frame can both real-time report.Therefore available frame count is compared and judge, be used for guaranteeing the real-time of signal feedback.
Communication system is carried out record to the situation of the SNR that every frame is gathered, and judge whether the SNR in the measurement period reaches the available frame count standard of available frame count defined, can feed back to communication system in real time with the variation that guarantees channel conditions, system then in time adjusts the exponent number of modulation system according to judged result.Described available frame count is meant that communication system in the measurement period receives the number of the frame that has reported SNR information.Described available frame count standard is meant the number of the minimum valid frame that reaches statistical requirements.
For available frame count is judged, need definition one-period frame number (Period
EffectiveCheck), the periodic frame numerical table is shown in the number of the frame that needs to carry out validity check in the measurement period; An available frame count standard (FrameNumber is set
Effective), be used for the lowest threshold of the number of the valid frame added up being adjudicated as in the measurement period.When adjudicating, system also needs the initial frame number (FrameNo of retention cycle validity check
Start), current frame number (FrameNo
Current) and current available frame count (FrameNumber
CurrentEffective).After this judgement finishes, the processing procedure that current frame number is promptly entered following one-period as the initial frame number of following one-period.
Its judging process is as follows:
If FrameNo
Current-FrameNo
Start=Period
EffectiveCheckThe time, then show and need carry out validity check the valid frame in this cycle frame number scope; Otherwise, for less than Period
EffectiveCheckSituation then do not handle.
Described validity check is that available frame count standard and current available frame count are compared, and meets the requirements if current valid frame numerical value, is then represented the available frame count in the measurement period greater than the available frame count standard; Otherwise, representing that the SNR of the collection in this measurement period does not reach the standard of validity check, the SNR that gathered in this measurement period this moment is all invalid, carries out zero clearing and handles, and gathers again and counts in next measurement period then.
Fig. 5 is a statistics and judging process flow chart in the embodiment of the invention, as shown in Figure 5, for convenience of description, introduces following parameter:
Liter rank statistics array [statistics frame number] (StatArrayForRise[StatFrameNumber]), the array that expression is used for gathering SNR, the statistics of available frame count when being used for the rising of modulation system exponent number;
Depression of order statistics array [statistics frame number] (StatArrayForDrop[StatFrameNumber]), the array that expression is used for gathering SNR, the statistics of available frame count when being used for the reduction of modulation system exponent number;
Current rising ratio (RiseRatio
Current): be illustrated in the measurement period, the available frame count that counts on is than certain ratio of the modulation system access door limit for height of high-order more relatively.
Rising ratio threshold value (RiseRatio
Fixed): the definite value of setting, represent in the measurement period that certain is the threshold value of the fixed ratio of available frame count under the modulation system of high-order more; The modulation system of corresponding different rank, this rising ratio threshold value are different accordingly.
Current decreasing ratio (DropRatio
Current): be illustrated in the measurement period, the available frame count that counts on than certain more the modulation system of low order withdraw from the low ratio of thresholding.
Decreasing ratio threshold value (DropRatio
Fixed): the definite value of setting, represent in the measurement period that certain is the threshold value of the fixed ratio of available frame count under the modulation system of low order more.The modulation system of corresponding different rank, this decreasing ratio threshold value are different accordingly.
Concrete statistics is as follows with judging process:
Step 501: the SNR information that collects is added up, draw RiseRatio
CurrentAnd DropRatio
Current
Described SNR information is added up, mainly be to StatArrayForRise[StatFrameNumber] array and StatArrayForDrop[StatFrameNumber] array travels through, the modulation system of current relatively exponent number, with certain more high-order or more the entering thresholding or withdraw from thresholding and compare of modulation system of low order, thereby obtain RiseRatio
CurrentAnd DropRatio
CurrentValue.
Step 502: according to the RiseRatio of statistics
CurrentAnd DropRatio
Current, respectively with RiseRatio
FixedAnd DropRatio
FixedCompare, and make corresponding judgement.
Concrete judging process is as follows:
If RiseRatio
Current〉=RiseRatio
Fixed, then execution in step 503, trigger modulation system to more high-order adjustment; Otherwise, execution in step 504, the exponent number of sufficient modulation system with thumb down rises the condition on rank, and the exponent number of keeping current modulation mode is constant, and waits for the arrival of next measurement period, enters the statistics and the judging process of next measurement period then;
If DropRatio
Current〉=DropRatio
Fixed, then execution in step 503, trigger modulation system to more low order adjustment; Otherwise, execution in step 504, the condition of the exponent number depression of order of sufficient modulation system with thumb down, the exponent number of keeping current modulation mode is constant, and waits for the arrival of next measurement period, and then enters the statistics and the judging process of next measurement period.
More than according to the SNR in the measurement period modulation system of wireless channel is carried out the process introduction that exponent number is adjusted for the present invention.In the process that the exponent number of modulation system is adjusted, the rising of the exponent number of modulation system or reduction also can be subdivided into following dual mode again:
Fig. 6 is that the modulation system exponent number raises and the situation of reduction schematic diagram in the embodiment of the invention, as shown in Figure 6:
1) modulation system of exponent number rising:
A, the mode that rises step by step, the modulation system of current relatively exponent number, each according to statistics only to the exponent number that raises of high-order more.Shown in a section among Fig. 6.
The mode of b, multistage rising, the modulation system of current relatively exponent number is adjusted to modulation system high-order according to statistics at every turn as much as possible.Shown in b section among Fig. 6.
2) modulation system of exponent number reduction:
C, the mode that descends step by step, the modulation system of current relatively exponent number only reduces an exponent number to low order more according to statistics is each.Shown in c section among Fig. 6.
The mode of d, multistage decline, the modulation system of current relatively exponent number is adjusted to lowest-order with modulation system according to statistics at every turn as much as possible.Shown in d section among Fig. 6.
To gather the DLSNR information of down channel, the process that the exponent number of down channel modulation system is adjusted is an example, describes application of the present invention in specific embodiment below.
Fig. 7 is the process flow diagram that the modulation system exponent number is adjusted in the embodiment of the invention, and as shown in the figure, this method of adjustment comprises:
Step 701: gather the DLSNR information of down channel, be kept in the array, with respect to current modulation system, the measurement period of setting high-order more or more the valid frame that collects DLSNR being added up under the modulation system of low order.
The DLSNR information of described collection down channel, be specially: the physical layer of portable terminal is measured DLSNR and is reported the MAC layer of self, by the MAC layer DLSNR is formed upstream message again and pass to the physical layer of self, be sent to the base station by air interface then, be kept in the memory with related data structure again, adopt array to preserve DLSNR information in the embodiment of the invention.
Similarly, gather the process of the ULSNR information of up channel, be specially: the physical layer of base station measures the MAC layer that can report the base station behind the ULSNR, is kept in the memory with related data structure, adopts array to preserve ULSNR information in the embodiment of the invention.
Described valid frame is meant the frame that has reported SNR information that communication system is received.
The measurement period that described setting is added up the frame that collects DLSNR is specially:
Measurement period (Period under the modulation system exponent number rising situation of down channel
DLRise), periodic quantity is set to the arbitrary frame numerical value in 1～200; When needed, by traversing operation, the available frame count that will rise in the rank statistics array [statistics frame number] (StatArrayForRise[StatFrameNumber]) comes out;
Measurement period (Period under the modulation system exponent number reduction situation of down channel
DLDrop), it is 1 that this cycle fixedly installs, and promptly the DLSNR information of the every frame in the measurement period is added up; When needed, by traversing operation, the available frame count that depression of order is added up in the array [statistics frame number] (StatArrayForDrop[StatFrameNumber]) comes out.
Step 702: determine cycle frame number (Period
EffectiveCheck), and definite available frame count standard, judge whether the available frame count in the current measurement period reaches statistical condition, if satisfy, then execution in step 704; Otherwise, execution in step 703.
Describedly judge whether the available frame count in the current measurement period reaches statistical condition, be meant that whether available frame count in the cycle frame number is more than or equal to the available frame count standard.If promptly satisfy Rule of judgment more than or equal to this available frame count standard, then the statistics of the available frame count in this measurement period enters subsequent processes; Otherwise,, illustrate that the SNR in this measurement period gathers the predetermined standard that do not reach if less than this available frame count standard, so the SNR that is gathered is invalid, to the collection result zero clearing, thereby this statistics also ignores, and system enters follow-up next measurement period and restarts statistics then.
Step 703 with the zero clearing as a result of the available frame count of current statistics, is returned step 701 then, enters next measurement period.
The zero clearing as a result of described available frame count with current statistics, enter next measurement period then, the statistics that is meant this measurement period does not reach the significance level that is enough to influence adjustment modulation system exponent number, therefore ignores this statistics, adds up again in next measurement period.
Step 704: the pairing rising ratio of the modulation system threshold value (RiseRatio that different rank is set
Fixed) and decreasing ratio threshold value (DropRatio
Fixed), and, calculate current rising ratio (RiseRatio according to the statistics of the available frame count in the measurement period under the current modulation mode
Current) and current decreasing ratio (DropRatio
Current), execution in step 705 or execution in step 707 then.
Step 705: with current rising ratio (RiseRatio
Current) and RiseRatio
FixedCompare, greater than rising ratio threshold value, then execution in step 706 as if current rising ratio; Otherwise, execution in step 709.
Step 706: the exponent number of modulation system is heightened, returned step 701 then, enter the processing procedure of next cycle.
Step 707: with current decreasing ratio (DropRatio
Current) and DropRatio
FixedCompare, greater than the decreasing ratio threshold value, then execution in step 708 as if current decreasing ratio; Otherwise, execution in step 709.
Step 708: the exponent number of modulation system is reduced, return step 701 then, enter the processing procedure of following one-period.
Step 709: the exponent number of keeping current modulation mode is constant, returns step 701 then, enters the processing procedure of following one-period.
In addition, the rising mode of the exponent number of modulation system described in the step 706 is further divided into following two kinds of situations: i.e. the mode that rises step by step and the mode of multistage rising.Shown in a section among Fig. 6 and b section.
The mode of the modulation system that raises step by step exponent number is applicable to that the speed of the SNR increase in the current measurement period of next measurement period internal ratio is more slow, and the ratio that rises in other words surpasses the situation of the rising ratio threshold value under the modulation system of current exponent number step by step; And the mode of multistage rising is applicable to that the SNR in the current measurement period of next measurement period internal ratio sharply increases, and the ratio that rises is in other words bypassed the immediate leadership and surpassed the situation of the rising ratio threshold value under the modulation system of current exponent number.
Similarly, the reduction mode of the exponent number of modulation system described in the step 708 is further divided into following two kinds of situations: i.e. the mode that descends step by step and the mode of multistage decline.Shown in c section among Fig. 6 and d section.
Reduce the mode of modulation system exponent number step by step, be applicable to that the speed of the SNR reduction in the current measurement period of next measurement period internal ratio is more slow, decreasing ratio is reduced to the situation greater than the decreasing ratio threshold value under the modulation system of current exponent number step by step in other words; And the mode of multistage decline is applicable to the rapid variation of SNR in the current measurement period of next measurement period internal ratio, in other words decreasing ratio the situation greater than the decreasing ratio threshold value under the modulation system of current exponent number of reducing to of bypassing the immediate leadership.
More than be the process that the exponent number of down channel modulation system is adjusted, to the process that the exponent number of the modulation system of up channel is adjusted, except the gatherer process difference of ULSNR, processing method is identical, therefore, here just repeats no more.
The above is preferred embodiment of the present invention only, is not to be used to limit protection scope of the present invention.
Claims (12)
1. level and smooth method of adjusting modulation system is characterized in that this method comprises:
A, gather the signal to noise ratio snr information of channel, and the measurement period of valid frame under the different rank modulation system is set;
B, judge whether the available frame count in the current measurement period reaches statistical condition, with the available frame count statistics zero clearing of current measurement period, and do not return step a when reaching statistical condition;
C, calculate current rising ratio or current decreasing ratio according to the available frame count in the measurement period, and respectively with the different rank modulation system of prior setting under rising ratio threshold value or decreasing ratio threshold value compare, if current rising ratio greater than rising ratio threshold value, is then heightened the exponent number of current modulation mode; If current decreasing ratio then reduces the exponent number of current modulation mode greater than the decreasing ratio threshold value; Otherwise the exponent number of keeping current modulation mode is constant.
2. method according to claim 1, it is characterized in that the described modulation system of step a comprises at least: binary phase shift keying BPSK, four phase absolute phase shift keying QPSK, eight phase absolute phase shift keying 8PSK, 16 attitude quadrature amplitude modulation 16QAM, 64 attitude quadrature amplitude modulation 64QAM and 128 attitude quadrature amplitude modulation 128QAM.
3. method according to claim 1 is characterized in that, the SNR information of the described collection channel of step a is specially: gather up signal to noise ratio ULSNR and descending signal to noise ratio DLSNR.
4. method according to claim 1 is characterized in that, the SNR information of the described collection channel of step a is specially: the base station physical layer measures the ULSNR value and reports the MAC layer as SNR information; And the physical layer of terminal measures DLSNR and reports self MAC layer, by the MAC layer DLSNR formed upstream message and passes to the physical layer of self, is sent to the base station by eating dishes without rice or wine as ULSNR information.
5. according to claim 1 or 4 described methods, it is characterized in that, the mode of the SNR information of the described collection channel of step a, be specially: adopt the SNR of the mode match exponents rising modulation system of stationary window to add up, adopt the SNR of the mode match exponents reduction modulation system of sliding window to add up.
6. method according to claim 5 is characterized in that, the described measurement period that is provided with of step a is specially: for the measurement period under the exponent number rising situation, periodic quantity is 1～200 frame; For the measurement period under the exponent number reduction situation, periodic quantity fixedly is changed to 1 frame.
7. method according to claim 1 is characterized in that step a further comprises: the SNR information of being gathered is kept at rises in rank statistics array or the depression of order statistics array.
8. method according to claim 1 is characterized in that step a further comprises: determine cycle frame number and corresponding available frame count standard under the different rank modulation system.
9. method according to claim 1 is characterized in that, step b is described to judge that whether the available frame count in the current measurement period reaches statistical condition, is specially: judge that whether the interior available frame count of measurement period is greater than the available frame count standard.
10. method according to claim 1 is characterized in that, described method also comprises: also comprised before step b:
In measurement period,, the available frame count that rises in rank statistics array or the depression of order statistics array is come out by traversing operation.
11. method according to claim 10 is characterized in that, the described mode of heightening the exponent number of current modulation mode of step c3 is specially: the mode of mode of Shang Shenging or multistage rising step by step.
12. method according to claim 10 is characterized in that, the mode of the exponent number of the described reduction current modulation mode of step c5 is specially: the mode of mode of Xia Jianging or multistage decline step by step.
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| CN1567758A (en) * | 2003-06-27 | 2005-01-19 | 上海贝尔阿尔卡特股份有限公司 | Self-adaptive modulating and coding method and device based on channel information second order statistics |
| CN1744481A (en) * | 2005-09-30 | 2006-03-08 | 上海贝豪通讯电子有限公司 | Adaptive transmission method in TD-SCDMA system |
| CN1956352A (en) * | 2005-10-28 | 2007-05-02 | Ut斯达康通讯有限公司 | Distribution method of transmitting antenna speed, power in V-BLAST system |
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| CN1744481A (en) * | 2005-09-30 | 2006-03-08 | 上海贝豪通讯电子有限公司 | Adaptive transmission method in TD-SCDMA system |
| CN1956352A (en) * | 2005-10-28 | 2007-05-02 | Ut斯达康通讯有限公司 | Distribution method of transmitting antenna speed, power in V-BLAST system |
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