Background technology
Traditional multicarrier modulation system is that high-speed data-flow is formed the data flow of a plurality of low speed by serial to parallel conversion, and then modulates corresponding carrier wave respectively, thereby constitutes the parallel transmission system that sends of a plurality of low-rate datas.But wherein a plurality of carrier waves that are used to modulate show as a plurality of overlapping the subcarrier of quadrature on frequency band.OFDM (OrthogonalFrequency Division Multiplexing, abbreviation OFDM) technology is a kind of special multi-carrier modulation technology, have between each subcarrier 1/2 overlapping, but at discrete Fourier transform (DFT) (Disperse Fourier Transform, being called for short DFT) maintenance is mutually orthogonal down in operation, receiving terminal can by the correlation demodulation technical point from, constitute data transmission system efficiently.The OFDM technology can improve spectrum efficiency greatly, utilize fast fourier transform (FastFourier Transfer simultaneously, be called for short FFT) and the hardware realization of inverse fast fourier transform (Inverse FastFourier Transfer is called for short IFFT), the realization of ofdm system can be simplified greatly.In addition, ofdm system can also utilize the Cyclic Prefix protection to reduce the intersymbol interference in front and back at interval, and can conveniently utilize frequency selectivity to resist the decline of wireless channel.Because the plurality of advantages of OFDM technology, the OFDM technology is widely used at present.Access scheme (OrthogonalFrequency Division Multiplexing Access based on orthogonal frequency division multiplexi, abbreviation OFDMA) system utilizes the OFDM technology to do multiplex technique, promptly by distributing different data subcarriers to distinguish different users to different user.Because transfer of data is used different mutually orthogonal subcarriers between the user, so transfer of data can the phase mutual interference between the user.And when subcarrier is distributed, can take into full account this user's wireless environment situation, make full use of frequency selectivity, distribute the data subcarrier of the most suitable transmission to the user, and, make power system capacity improve by the allocation schedule optimization Algorithm.
(Hybrid automatic Request withIncremental Redundancy is asked in mixing with steadily increase redundancy automatically, be called for short H-ARQ with IR) be a kind of link adaptation techniques, its basic process is: data sending terminal is encoded to information sets, encoded packets is divided into some fragments, and each transmission sends wherein one or more fragments.Data receiver is decoded to the encoded packets fragment that receives, if can not be correctly decoded, then feeds back to data sending terminal request repeat data.Data sending terminal then sends some fragments again, retransmitting the fragment that sends can be identical or different with the fragment that last time sent, data receiver is after receiving the fragment of re-transmission, when decoding, in conjunction with the encoded packets fragment of last time transmission and the encoded packets fragment of re-transmission, make full use of the relevant information that they carry, improve the decoding probability.The use of H-ARQ with IR technology has improved the error correcting capability of Data Receiving in the Radio Access Network, and can adapt to the variation of Radio Link automatically, thereby has improved transmission performance.
In wireless system based on the OFDMA technology, when wireless access terminal (Accessterminal is called for short AT) sends data to Radio Access Network when (Access network is called for short AN), AT determines the transmitting power of Traffic Channel and control channel according to the certain power control algolithm.The WiMAX that proposes such as QualCom company inserts in standard 802.20 systems, for the multiplexing OFDMA that all is based on of the transmission of data, during promptly each the transmission, distribute to the AT sub-carrier resources by AN, each AT uses the data subcarrier of distributing to oneself to carry out data-modulated and sends (reverse data transmission).In the same sector, each AT uses different sub-carrier resources, has guaranteed the orthogonality of transmission, makes that transfer of data can the phase mutual interference between the user.AN constantly adjusts the power of AT with reference to control channel by power control information, and AT determines the power of Traffic Channel by the certain power control algolithm then, and carries out the emission of Traffic Channel and control channel.Power control is the key technology that guarantees link transmission quality.But each AN is in the allocation of subcarriers resource, certain delay is all arranged, so AN does not also know the actual transmission power situation of AT constantly, the result just might cause at the real data x time, the power overload of AT, be the maximum transmit power limit that the power resource (the power sums that the channel of all emissions needs) of AT actual needs surpasses AT, AT will have to carry out power attenuation this moment, and the power attenuation of some channel is met the requirements with guaranteed output.
Oppositely, cover situations such as more weak owing to be in deep fading zone or travelling carriage apart from base station signal far away, travelling carriage will promote transmitting power to satisfy the received power level at receiving terminal, but when surpassing the travelling carriage maximum transmission power, travelling carriage need reduce the transmitting power on some subcarrier.
At forward direction, cover situations such as more weak owing to be in deep fading zone or travelling carriage apart from base station signal far away, base-station will promote the forward emitting power of this travelling carriage to satisfy the received power level at the travelling carriage receiving terminal, but surpass when the base station power amplifier is maximum to allow transmitting power, the transmitting power on some subcarrier need be reduced in the base station.
When emergent power transships, according to 802.20 agreements, AT will independently determine the priority of each channel, then according to the priority level of these channels, whether decision closes (gate-off) one or more of send channels, meet the demands with guaranteed output, promptly preferentially close the low channel of priority.In 802.20 systems, main backward channel comprises that R-CQI (is used to report the forward channel quality, if close emission, to cause very big influence to forward data transmission), (the affirmation channel of response forward data transmission is if close emission for R-ACKCH, to cause very big influence to forward data transmission), R-DCH (reverse data channel, if close emission, then reverse data can not transmit).Oppositely also there is some other control channel: such as R-REQCH (reverse Request channel, be mainly used in the reverse resource bid information that reports, as reverse buffer size, QoS priority etc., be used to carry out back scheduling), R-BFCH (reverse BeamForming channel, be used to report the relevant information of carrying out MIMO scheduling needs) or the like, but they all are to send in the cycle, priority is lower, and the power of these control channels itself is just very low, in power overload, even close emission, can significantly not reduce transmitting power yet.In reality system, the main cause of power overload is because scheduling the time is the too many sub-carrier resources of traffic channel assignments, and in actual transmissions constantly, the wireless environment of AT can not be supported so much sub-carrier resources, the result causes the data channel transmitting power too high, thereby makes the AT transmission power overload.So processing according to 802.20 agreements, when overload of reverse power, close channels transmit, or can impact forward data transmission, need close too many channel and could recover power, these operations all have a significant impact the stable and transmission performance of system.
Can find out that from above-described content the method for the power overload situation that occurs when handling wireless data transmission in the prior art can produce very big influence for the stability and the transmission performance of communication system.
Therefore, be necessary to improve existing service channel power damped system, with when emergent power when overload in the wireless data transmission process, can under situation the about stability and the transmission performance of communication system not produced a very large impact, realize normal transfer of data.
Summary of the invention
In view of the above problems, the present invention aims to provide data transmission method and system and device, with when emergent power in the wireless data transmission process transships, Traffic Channel is handled, thereby under situation the about stability and the transmission performance of communication system not produced a very large impact, normally transmit data.
According to an aspect of the present invention, a kind of data transmission method has been proposed, may further comprise the steps: S101, be the one or more running time-frequency resource perforation patterns of Traffic Channel predefine, when transmitting terminal detects transmission power overload, close one or more subcarriers of punch position corresponding service channel in the running time-frequency resource perforation pattern according to a running time-frequency resource perforation pattern of from one or more running time-frequency resource perforation patterns, selecting, wherein, the running time-frequency resource perforation pattern illustrates the state of each subcarrier of Traffic Channel; S102, transmitting terminal transmits data through ovennodulation by the subcarrier of not closing in the Traffic Channel to receiving terminal, and all subcarriers by Traffic Channel send running time-frequency resource perforation pattern information to receiving terminal simultaneously; And S103, receiving terminal obtains the running time-frequency resource perforation pattern according to running time-frequency resource perforation pattern information, and according to the data of running time-frequency resource perforation pattern reception from transmitting terminal.
In above-mentioned data transmission method, among the step S101, the situation that transmitting terminal detects transmission power overload comprises following a kind of at least: the wireless access terminal detects the reverse link transmission power overload, Radio Access Network detects the emission power of forward link overload.
In above-mentioned data transmission method, among the step S101, the method of pre-defined one or more Traffic Channel running time-frequency resource perforation patterns comprises following at least a: do not punch in the position corresponding to subcarrier in the running time-frequency resource perforation pattern, represents all sub-carrier frequencies normal power emissions; Partly punched in the position corresponding to subcarrier in the running time-frequency resource perforation pattern, expression partial data sub-carrier frequencies is closed emission, only keeps pilot subcarrier frequencies and other data subcarrier frequency emission; All being punched in the position corresponding to subcarrier in the running time-frequency resource perforation pattern, represents that all data subcarrier frequencies close emission, only keeps the pilot subcarrier frequencies emission.
In above-mentioned data transmission method, the part drilling method comprises following at least a: regularly the running time-frequency resource perforation pattern is punched; And by randomly the running time-frequency resource perforation pattern being punched.
In above-mentioned data transmission method, among the step S102, the additional character that running time-frequency resource perforation pattern information is mapped on the complex number plane transmits.
In above-mentioned data transmission method, among the step S102, transmit by code division multiplexing through perforation pattern symbol after the mapping and the data on the Traffic Channel through ovennodulation.
In above-mentioned data transmission method, step S103 comprises: S1031, receiving terminal carry out demodulation to the received signal, recover running time-frequency resource perforation pattern information, determine the running time-frequency resource perforation pattern; S1032, receiving terminal is determined in the Traffic Channel subcarrier of transmission data according to the running time-frequency resource perforation pattern, receives data and handles from subcarrier.
According to a further aspect in the invention, a kind of data transmission system has been proposed, comprise: running time-frequency resource perforating device 301, it is distolateral to be positioned at emission, it stores the predefined one or more running time-frequency resource perforation patterns of promising Traffic Channel, when transmitting terminal detects transmission power overload, close one or more subcarriers of the punch position corresponding service channel in the running time-frequency resource perforation pattern according to a running time-frequency resource perforation pattern of from one or more running time-frequency resource perforation patterns, selecting, wherein, the running time-frequency resource perforation pattern illustrates the state of each subcarrier of Traffic Channel; Information carrying means 302, it is distolateral to be positioned at emission, and the subcarrier that is used for not closing by Traffic Channel is to the data of receiving terminal transmission through ovennodulation, and all subcarriers by Traffic Channel send running time-frequency resource perforation pattern information to receiving terminal simultaneously; And information acquisition device 303, it is distolateral to be positioned at reception, be used for obtaining the running time-frequency resource perforation pattern according to running time-frequency resource perforation pattern information, and according to the data of running time-frequency resource perforation pattern reception from transmitting terminal.
In the running time-frequency resource perforating device in above-mentioned data transmission system, the situation that transmitting terminal detects transmission power overload comprises following a kind of at least: the wireless access terminal detects the reverse link transmission power overload, Radio Access Network detects the emission power of forward link overload.
In the running time-frequency resource perforating device in above-mentioned data transmission system, the define method of predefined one or more Traffic Channel running time-frequency resource perforation patterns comprises following at least a: do not punch in the position corresponding to subcarrier in the running time-frequency resource perforation pattern, represents all sub-carrier frequencies normal power emissions; Partly punched in the position corresponding to subcarrier in the running time-frequency resource perforation pattern, expression partial data sub-carrier frequencies is closed emission, only keeps pilot subcarrier frequencies and other data subcarrier frequency emission; All being punched in the position corresponding to subcarrier in the running time-frequency resource perforation pattern, represents that all data subcarrier frequencies close emission, only keeps the pilot subcarrier frequencies emission.
In above-mentioned data transmission system, the part drilling method comprises following at least a: regularly the running time-frequency resource perforation pattern is punched; And randomly the running time-frequency resource perforation pattern is punched.
In the information carrying means in above-mentioned data transmission system, the additional character that running time-frequency resource perforation pattern information is mapped on the complex number plane transmits.
In the information carrying means in above-mentioned data transmission system, transmit by code division multiplexing through perforation pattern symbol after the mapping and the data on the Traffic Channel through ovennodulation.
In above-mentioned data transmission system, information acquisition device comprises: running time-frequency resource perforation pattern acquisition module 3031, be used for carrying out to the received signal demodulation, and recover running time-frequency resource perforation pattern information, determine the running time-frequency resource perforation pattern; Data acquisition facility 3032 is used for determining according to the running time-frequency resource perforation pattern subcarrier of Traffic Channel transmission data, receives data and handles from subcarrier.
In accordance with a further aspect of the present invention, a kind of data transmission device has been proposed, comprise: information sending module 401, wherein store the method for one or more channels of managing business, when detecting transmission power overload, the method of at least a channel of selecting the method according to the channel of managing business from one or more of the managing business channel of managing business, and the information of the channel method of will managing business and modulated data send the information acquisition module to by treated Traffic Channel; Information acquisition module 402 is used for the method according to the information acquisition process Traffic Channel of the channel method of managing business, and obtains the data that treated Traffic Channel transmits according to the method for the channel of managing business.
In above-mentioned data transmission device, information sending module comprises: running time-frequency resource punching submodule 4011, it stores the predefined one or more running time-frequency resource perforation patterns of promising Traffic Channel, when detecting transmission power overload, close one or more subcarriers of the punch position corresponding service channel of running time-frequency resource perforation pattern according to a running time-frequency resource perforation pattern of from one or more running time-frequency resource perforation patterns, selecting, wherein, the running time-frequency resource perforation pattern illustrates the state of each subcarrier of Traffic Channel; Message transmission submodule 4012, the subcarrier that is used for not closing by Traffic Channel transmits the data through ovennodulation, and all subcarriers by Traffic Channel transmit running time-frequency resource perforation pattern information simultaneously.
In above-mentioned data transmission device, in the running time-frequency resource punching submodule, the situation that detects transmission power overload comprises following a kind of at least: the wireless access terminal detects the reverse link transmission power overload, Radio Access Network detects the emission power of forward link overload.
In above-mentioned data transmission device, in the running time-frequency resource punching submodule, the define method of predefined one or more Traffic Channel running time-frequency resource perforation patterns comprises following at least a: do not punch in the position corresponding to subcarrier in the running time-frequency resource perforation pattern, represents all sub-carrier frequencies normal power emissions; Partly punched in the position corresponding to subcarrier in the running time-frequency resource perforation pattern, expression partial data sub-carrier frequencies is closed emission, only keeps pilot subcarrier frequencies and other data subcarrier frequency emission; All being punched in the position corresponding to subcarrier in the running time-frequency resource perforation pattern, represents that all data subcarrier frequencies close emission, only keeps the pilot subcarrier frequencies emission.
In above-mentioned data transmission device, the part drilling method comprises following at least a: regularly the running time-frequency resource perforation pattern is punched; And by randomly the running time-frequency resource perforation pattern being punched.
In above-mentioned data transmission device, in the message transmission submodule, the additional character that running time-frequency resource perforation pattern information is mapped on the complex number plane transmits.
In above-mentioned data transmission device, in the message transmission submodule, transmit by code division multiplexing through perforation pattern symbol after the mapping and the data on the Traffic Channel through ovennodulation.
In above-mentioned data transmission device, the information acquisition module comprises: the running time-frequency resource perforation pattern obtains submodule 4021, is used for carrying out to the received signal demodulation, recovers running time-frequency resource perforation pattern information, determines the running time-frequency resource perforation pattern; Data are obtained submodule 4022, are used for determining according to the running time-frequency resource perforation pattern subcarrier of Traffic Channel transmission data, receive data and handle from subcarrier.
In sum, in the wireless data transmission process, when overload appears in power,,, reach the purpose of power attenuation with the running time-frequency resource disconnection of transmission by choosing certain running time-frequency resource perforation pattern.Interference to the Traffic Channel normal transmission can be ignored.The invention solves the problem of the normal transmission data under the power overload situation in the wireless data transmission process, thereby improved the stability and the transmission performance of communication system.
Embodiment
Also the present invention is described in detail in conjunction with the embodiments below with reference to accompanying drawing.
With reference to shown in Figure 1, illustrate according to a kind of data transmission method of the present invention.This method may further comprise the steps: S101, be the one or more running time-frequency resource perforation patterns of Traffic Channel predefine, when transmitting terminal detects transmission power overload, close one or more subcarriers of punch position corresponding service channel in the running time-frequency resource perforation pattern according to a running time-frequency resource perforation pattern of from one or more running time-frequency resource perforation patterns, selecting, wherein, the running time-frequency resource perforation pattern illustrates the state of each subcarrier of Traffic Channel; S102, transmitting terminal transmits data through ovennodulation by the subcarrier of not closing in the Traffic Channel to receiving terminal, and all subcarriers by Traffic Channel send running time-frequency resource perforation pattern information to receiving terminal simultaneously; And S103, receiving terminal obtains the running time-frequency resource perforation pattern according to running time-frequency resource perforation pattern information, and according to the data of running time-frequency resource perforation pattern reception from transmitting terminal.
In above-mentioned data transmission method, among the step S101, the situation that transmitting terminal detects transmission power overload comprises following a kind of at least: the wireless access terminal detects the reverse link transmission power overload, Radio Access Network detects the emission power of forward link overload.
In above-mentioned data transmission method, among the step S101, the method of pre-defined one or more Traffic Channel running time-frequency resource perforation patterns comprises following at least a: do not punch in the position corresponding to subcarrier in the running time-frequency resource perforation pattern, represents all sub-carrier frequencies normal power emissions; Partly punched in the position corresponding to subcarrier in the running time-frequency resource perforation pattern, expression partial data sub-carrier frequencies is closed emission, only keeps pilot subcarrier frequencies and other data subcarrier frequency emission; All being punched in the position corresponding to subcarrier in the running time-frequency resource perforation pattern, represents that all data subcarrier frequencies close emission, only keeps the pilot subcarrier frequencies emission.
In above-mentioned data transmission method, the part drilling method comprises following at least a: regularly the running time-frequency resource perforation pattern is punched; And by randomly the running time-frequency resource perforation pattern being punched.
In above-mentioned data transmission method, among the step S102, the additional character that running time-frequency resource perforation pattern information is mapped on the complex number plane transmits.
In above-mentioned data transmission method, among the step S102, transmit by code division multiplexing through perforation pattern symbol after the mapping and the data on the Traffic Channel through ovennodulation.
In above-mentioned data transmission method, step S103 comprises (as shown in Figure 2): S1031, and receiving terminal carries out demodulation to the received signal, recovers running time-frequency resource perforation pattern information, determines the running time-frequency resource perforation pattern; S1032, receiving terminal is determined in the Traffic Channel subcarrier of transmission data according to the running time-frequency resource perforation pattern, receives data and handles from subcarrier.
With reference to shown in Figure 3, illustrate according to data transmission system of the present invention.This system comprises: running time-frequency resource perforating device 301, it is distolateral to be positioned at emission, it stores the predefined one or more running time-frequency resource perforation patterns of promising Traffic Channel, when transmitting terminal detects transmission power overload, close one or more subcarriers of the punch position corresponding service channel in the running time-frequency resource perforation pattern according to a running time-frequency resource perforation pattern of from one or more running time-frequency resource perforation patterns, selecting, wherein, the running time-frequency resource perforation pattern illustrates the state of each subcarrier of Traffic Channel; Information carrying means 302, it is distolateral to be positioned at emission, and the subcarrier that is used for not closing by Traffic Channel is to the data of receiving terminal transmission through ovennodulation, and all subcarriers by Traffic Channel send running time-frequency resource perforation pattern information to receiving terminal simultaneously; And information acquisition device 303, it is distolateral to be positioned at reception, be used for obtaining the running time-frequency resource perforation pattern according to running time-frequency resource perforation pattern information, and according to the data of running time-frequency resource perforation pattern reception from transmitting terminal.
In the running time-frequency resource perforating device in above-mentioned data transmission system, the situation that transmitting terminal detects transmission power overload comprises following a kind of at least: the wireless access terminal detects the reverse link transmission power overload, Radio Access Network detects the emission power of forward link overload.
In the running time-frequency resource perforating device in above-mentioned data transmission system, the define method of predefined one or more Traffic Channel running time-frequency resource perforation patterns comprises following at least a: do not punch in the position corresponding to subcarrier in the running time-frequency resource perforation pattern, represents all sub-carrier frequencies normal power emissions; Partly punched in the position corresponding to subcarrier in the running time-frequency resource perforation pattern, expression partial data sub-carrier frequencies is closed emission, only keeps pilot subcarrier frequencies and other data subcarrier frequency emission; All being punched in the position corresponding to subcarrier in the running time-frequency resource perforation pattern, represents that all data subcarrier frequencies close emission, only keeps the pilot subcarrier frequencies emission.
In above-mentioned data transmission system, the part drilling method comprises following at least a: regularly the running time-frequency resource perforation pattern is punched; And by randomly the running time-frequency resource perforation pattern being punched.
In the information carrying means in above-mentioned data transmission system, the additional character that running time-frequency resource perforation pattern information is mapped on the complex number plane transmits.
In the information carrying means in above-mentioned data transmission system, transmit by code division multiplexing through perforation pattern symbol after the mapping and the data on the Traffic Channel through ovennodulation.
In above-mentioned data transmission system, information acquisition device comprises: running time-frequency resource perforation pattern acquisition module 3031, be used for carrying out to the received signal demodulation, and recover running time-frequency resource perforation pattern information, determine the running time-frequency resource perforation pattern; Data acquisition facility 3032 is used for determining according to the running time-frequency resource perforation pattern subcarrier of Traffic Channel transmission data, receives data and handles from subcarrier.
With reference to shown in Figure 4, illustrate according to a kind of data transmission device of the present invention.This device comprises: information sending module 401, wherein store the method for one or more channels of managing business, when detecting transmission power overload, the method of at least a channel of selecting the method according to the channel of managing business from one or more of the managing business channel of managing business, and the information of the channel method of will managing business and modulated data send the information acquisition module to by treated Traffic Channel; Information acquisition module 402 is used for the method according to the information acquisition process Traffic Channel of the channel method of managing business, and obtains the data that treated Traffic Channel transmits according to the method for the channel of managing business.
In above-mentioned data transmission device, information sending module comprises: running time-frequency resource punching submodule 4011, it stores the predefined one or more running time-frequency resource perforation patterns of promising Traffic Channel, when detecting transmission power overload, close one or more subcarriers of the punch position corresponding service channel of running time-frequency resource perforation pattern according to a running time-frequency resource perforation pattern of from one or more running time-frequency resource perforation patterns, selecting, wherein, the running time-frequency resource perforation pattern illustrates the state of each subcarrier of Traffic Channel; Message transmission submodule 4012, the subcarrier that is used for not closing by Traffic Channel transmits the data through ovennodulation, and all subcarriers by Traffic Channel transmit running time-frequency resource perforation pattern information simultaneously.
In above-mentioned data transmission device, in the running time-frequency resource punching submodule, the situation that detects transmission power overload comprises following a kind of at least: the wireless access terminal detects the reverse link transmission power overload, Radio Access Network detects the emission power of forward link overload.
In above-mentioned data transmission device, in the running time-frequency resource punching submodule, the define method of predefined one or more Traffic Channel running time-frequency resource perforation patterns comprises following at least a: do not punch in the position corresponding to subcarrier in the running time-frequency resource perforation pattern, represents all sub-carrier frequencies normal power emissions; Partly punched in the position corresponding to subcarrier in the running time-frequency resource perforation pattern, expression partial data sub-carrier frequencies is closed emission, only keeps pilot subcarrier frequencies and other data subcarrier frequency emission; All being punched in the position corresponding to subcarrier in the running time-frequency resource perforation pattern, represents that all data subcarrier frequencies close emission, only keeps the pilot subcarrier frequencies emission.
In above-mentioned data transmission device, the part drilling method comprises following at least a: regularly the running time-frequency resource perforation pattern is punched; And by randomly the running time-frequency resource perforation pattern being punched.
In above-mentioned data transmission device, in the message transmission submodule, the additional character that running time-frequency resource perforation pattern information is mapped on the complex number plane transmits.
In above-mentioned data transmission device, in the message transmission submodule, transmit by code division multiplexing through perforation pattern symbol after the mapping and the data on the Traffic Channel through ovennodulation.
In above-mentioned data transmission device, the information acquisition module comprises: the running time-frequency resource perforation pattern obtains submodule 4021, is used for carrying out to the received signal demodulation, recovers running time-frequency resource perforation pattern information, determines the running time-frequency resource perforation pattern; Data are obtained submodule 4022, are used for determining according to the running time-frequency resource perforation pattern subcarrier of Traffic Channel transmission data, receive data and handle from subcarrier.
With reference to figure 5, shown in Figure 6, the method for a kind of service channel power of decaying provided by the invention is further specified.This method is the transmitting power by control Traffic Channel each subcarrier, rather than the transmitting power of closing Traffic Channel and other control channels realizes the decay of service channel power.For example, in the OFDMA system, the transmission of reverse traffic channel generally all is that the time by as shown in Figure 5 realizes.
Laterally be time shaft, each grid is represented 1 OFDM symbol period, vertically is frequency axis, and each grid is represented 1 subcarrier.In 802.20, by 16 subcarriers and 8 OFDM symbols, form a piece (block), as the time of reverse data transmission, can distribute a plurality of such Resource Block to carry out transfer of data to AT.Black box is represented the pilot tone inserted, and it does not transmit data, is used for channel estimating.
When the reverse emergent power of AT transshipped, AT can select certain frequency patterns (as shown in Figure 6) to carry out the gate-off of subcarrier emission, and needn't close the whole service channel.
Wherein, the grey grid represents to launch the subcarrier by gate-off, represents this virgin's carrier wave zero energy emission.At the present frame x time, when AT detects overload of reverse power, AT can independently determine to close the emission of which subcarrier (by the perforation pattern decision of selecting, the position of all grey grids as shown in FIG. is considered to a perforation pattern at specific time), after AT power recovered, AT can continue to launch on all subcarriers.
In order to guarantee the accuracy of channel estimating, pilot sub-carrier can not be closed emission.
The method of pre-defined one or more groups Traffic Channel running time-frequency resource perforation pattern comprises:
1, do not punch the normal power emission;
2, punch on 1/2 running time-frequency resource, keep 1/2 running time-frequency resource, pilot sub-carrier does not punch, and total transmitting power reduces 3dB;
3, punch on 3/4 running time-frequency resource, keep 1/4 running time-frequency resource, pilot sub-carrier does not punch, and total transmitting power reduces 6dB;
4, punch on all data running time-frequency resources, pilot sub-carrier does not punch.
Wherein, the Traffic Channel perforation pattern specifically has following several:
1, regular pattern composite, i.e. the mode of making an appointment according to the data transmit-receive both sides, such as:
A. 1/2 resource is punched:, choose 0,2,4,6 subcarriers such as grade at OFDM symbol 1; At OFDM symbol 2, choose 1,3,5,7 subcarriers such as grade; At OFDM symbol 3, choose 0,2,4,6 subcarriers such as grade; At OFDM symbol 4, choose 1,3,5,7 subcarriers such as grade, the rest may be inferred;
B. 3/4 resource is punched:, choose 0,4,8,12 subcarriers such as grade at OFDM symbol 1; At OFDM symbol 2, choose 2,6,10,14 subcarriers such as grade; At OFDM symbol 3, choose 0,4,8,12 subcarriers such as grade; At OFDM symbol 4, choose 2,6,10,14 subcarriers such as grade; The rest may be inferred.
By the perforation pattern of design like this, can make full use of frequency diversity gain, i.e. the dispersed punching of frequency sub-carrier resource makes full use of the characteristics of frequency selectivity.
2: stochastic pattern, such as passing through to produce the m sequence of particular phases or other pseudo random sequence, each bit of sequence and a running time-frequency resource correspondence:
A. 1/2 resource is punched: bit is represented this resource for " 1 " and is kept, is perforated for " 0 " represents this resource;
B. 3/4 resource is punched: first " 1 " bit represents that this resource keeps, and second " 1 " bit represents that this resource is perforated, and the 3rd " 1 " bit represents that this resource is retained, and the like, " 0 " bit represents that this resource is perforated.
By the perforation pattern of design like this, can make full use of cell interference diversity gain, i.e. the effect of interference randomization.So punctured sequences needs the data transmit-receive both sides to determine, or both sides can both determine the punctured sequences that synchronization uses according to a certain rule.Such as the generation of sequence being followed sector mark, information such as time combine.
The running time-frequency resource perforation pattern is with two bit information bit representations.Possible Traffic Channel running time-frequency resource perforation pattern sends and receives both sides and need know that all this can consult mutually to determine by AN and AT.
When transmitting terminal punched to running time-frequency resource, receiving terminal must be known the pattern of punching, otherwise the noise of the position that is perforated will greatly disturb the demodulation code operations of receiving terminal.
So can design following running time-frequency resource perforation pattern information transmission mode, but be not limited to this method:
2bit information:
00: expression pattern 1;
01: expression pattern 2;
10: expression pattern 3;
11: expression pattern 4.
Four symbols can be designed to 4 points on the complex plane: 3 equidistant points on the center of circle and the unit circle.For example:
Transmitted 00 o'clock: power is 0, is equivalent to not send any traffic channel signal;
Transmitted 01 o'clock: sending symbol is 1, and power is very low with respect to Traffic Channel, for example is-20dB;
Transmitted 10 o'clock: sending symbol is
Power is very low with respect to Traffic Channel, for example is-20dB;
Transmitted 11 o'clock: sending symbol is
Power is very low with respect to Traffic Channel, for example is-20dB;
This symbol generates the modulation signal on the running time-frequency resource through certain scrambler sequence scrambling, and wherein, the scrambler sequence of this scrambler sequence and traffic channel symbols is low relevant.
The operating process of transmitting terminal is as follows:
Transmitting terminal is judged the transmitting power situation that exceeds standard, and selects one of four kinds of hole knockouts, and the encoded packets fragment is launched with the running time-frequency resource that is not perforated, and finishes a HARQ transmission.The encoded packets fragment is identical under time-frequency resource mapping and the normal mode of operation, and running time-frequency resource is perforated and only has influence on the coded identification number that each HARQ transmits.In the transmitting business channel, distributing to (all running time-frequency resources that comprise punching and be not perforated) transmission running time-frequency resource perforation pattern information on all running time-frequency resources of Traffic Channel.Running time-frequency resource perforation pattern information channel and Traffic Channel be actual to have constituted code division multiplexing.
The operating process of receiving terminal is as follows:
Receiving terminal when whenever receiving the signal of a HARQ transmission, demodulation running time-frequency resource perforation pattern information channel at first, demodulation Traffic Channel then.Its concrete steps are as follows:
1, uses the OFDM demodulation operation that the signal on the running time-frequency resource that receives is recovered, and carry out channel equalization with the result of channel estimating;
2, carry out descrambling with the signal of running time-frequency resource perforation pattern information channel scrambler sequence after to channel equalization, utilize behind the descrambling distance metric of four symbolic points on the data and complex plane, utilization Viterbi algorithm carries out the maximum likelihood decoding operation, obtains the running time-frequency resource perforation pattern of this time HARQ transmission;
3, on the basis of step 2, carry out interference eliminated, reduce the interference that Traffic Channel is subjected to, with the Traffic Channel scrambler sequence signal after the process interference eliminated is carried out descrambling then, the perforation pattern that utilizes step 2 to obtain is then separated mediation HARQ IR decode operation normally.
Because the speed that running time-frequency resource perforation pattern information channel transmits is very low, so its power ratio with respect to Traffic Channel can be very low, so can ignore the interference of Traffic Channel.Simultaneously, the high spread processing gain of code division multiplexing makes running time-frequency resource perforation pattern information channel still can obtain enough good demodulation performance.And the design of this code division multiplexing is expanded easily with the transmission more information, and Traffic Channel is kept transparent.
From above-mentioned steps as can be seen, utilize running time-frequency resource hole knockout and HARQ IR operation to can be good at seamless combination, to the HARQ operation transparent.
The front is by the agency of, in the reverse data transmission course of OFDMA system, power overload is owing to distribute too many subcarrier mostly, by the present invention, to some subcarrier emission carrying out gate-off, can guarantee can not launched with normal power by the sub-carrier resources of gate-off, the power of AT remains on normal condition simultaneously.Simultaneously, in existing wireless access system, in data transmission procedure, all used the HARQ technology, retransmitted and channel-decoding, also can guarantee the correctness of transfer of data by HARQ.Also can close simultaneously the emission of other control channels, so just can not cause too much influence the transmission of forward data.Wherein, about the selection of perforation pattern, situation that need to consider current actual power overload is judged and is chosen only perforation pattern.
In sum, in wireless data transmission process, when overload appears in power,, the running time-frequency resource that is perforated is carried out gate-off, reach the purpose of power attenuation by choosing certain running time-frequency resource perforation pattern based on OFDMA.Interference to the Traffic Channel normal transmission can be ignored, and can with the good seamless combination of HARQ-IR, to the HARQ operation transparent, HARQ operation is not had influence.The invention solves the problem of the normal transmission data under the power overload situation in the wireless data transmission process, thereby improved the stability and the transmission performance of communication system.