CN101167269B - Adaptive data multiplexing method in ofdma system and transmission/reception apparatus thereof - Google Patents

Abstract

A transmission/reception method and apparatus in an Orthogonal Frequency Division Multiplexing (OFDM)-based wireless communication system are provided, in which a data transmitter adaptively selects a multiplexing scheme according to a code rate of the transmission packet or an effective SNR of a wireless channel for a corresponding terminal, when transmitting a packet data channel. The adaptive multiplexing scheme is equal in concept to a scheme of adaptively implementing unitary precoding. The unitary precoded multiplexing includes Orthogonal Frequency code Domain Multiplexing (OFCDM), Fast Fourier Transform-Spread-OFDM (FFT-S-OFDM), Fast Frequency Hopping-OFDM (FFH-OFDM), and the like. The method and apparatus adaptively selects the multiplexing scheme and transmits/receives data using the selected multiplexing scheme, thereby improving reception performance of the packet data.

Description

Adaptive data multiplexing method in the orthogonal frequency division multiple access system and transmission/receiving system thereof

Technical field

The present invention relates generally to use the communication system of multiple access scheme.More specifically; The present invention relates to select best multiplexing scheme and use selected multiplexing scheme to send the transmission/method of reseptance and the device of data, to improve the receptivity of the data of in the system of use, sending based on the multiple access scheme transmission/reception data of OFDM (OFDM) according to data transmission situation.

Background technology

Recently, in field of wireless communications systems, carry out the research about OFDM (OFDM) energetically, this to the high speed data transfer through wireless channel of great use.OFDM, a kind of scheme of using multicarrier to send data is one type and before sending, the circulation of serial incoming symbol is changed to parallel symbol and utilizes the multi-carrier modulation such as a plurality of each symbol of quadrature subcarrier modulation of channel subcarrier.

Fig. 1 is the block diagram that the structure of the transmitter that is used for general ofdm system is shown.

With reference to Fig. 1, the transmitter of general ofdm system comprises channel encoder 101, modulator 102, serial-to-parallel (S/P) transducer 103, contrary FFT (IFFT) unit 104, parallel-to-serial (P/S) transducer 105 and Cyclic Prefix (CP) inserter 106.

101 pairs of input information bit streams of channel encoder are carried out chnnel coding.Usually, use convolution coder, turbo encoder or low-density checksum (LDPC) encoder as channel encoder 101.

Quadriphase PSK (QPSK), 8 phase shift keyings (PSK) or 16 quadrature amplitude modulation (qam)s are carried out in the output of 102 pairs of channel encoders 101 of modulator.Though not shown among Fig. 1, those skilled in the art obviously can know, can between parts 101 and 102, add the rate-matched unit that is used to carry out repetition and perforation.

It is the function of parallel signal that S/P transducer 103 has the conversion of signals that is used for from modulator 102 outputs.The output of the 104 pairs of S/P transducers 103 in IFFT unit is carried out IFFT and is calculated.

P/S transducer 105 is changed back serial signal with the output of IFFT unit 104.CP inserter 106 has the function that is used for to the output signal pended cyclic prefix (CP) of P/S transducer 105.

A kind of improved OFDM multiplexing scheme is arranged, and wherein transmitter is carried out hadamard (Hadamard) conversion to modulation symbol in frequency domain before sending.This scheme is commonly referred to multicarrier sign indicating number territory multiplexing (MC-CDM) or orthogonal frequency sign indicating number territory multiplexing (OFCDM).

Fig. 2 is the block diagram that the structure of general normalization precoding OFDM transmitter is shown.

With reference to Fig. 2, general normalization precoding OFDM transmitter comprises channel encoder 201, modulator 202, normalization precoder 203, S/P transducer 204, contrary FFT (IFFT) unit 205, P/S transducer 206 and CP inserter 207.

201 pairs of input information bit streams of channel encoder are carried out chnnel coding.Usually, use convolution coder, turbo encoder or LDPC encoder as channel encoder 201.

QPSK, 8PSK or 16QAM modulation are carried out in the output of 202 pairs of channel encoders 201 of modulator.Though not shown among Fig. 2, those skilled in the art obviously can know, can between parts 201 and 202, add the rate-matched unit that is used to carry out repetition and perforation.

Normalization precoder 203 is common normalization precoders, will describe the various examples of normalization precoding after a while with reference to Fig. 3 A to 3C.

S/P transducer 204 has that to be used for the output conversion of signals from modulator 202 be the function of parallel signal.The output of the 205 pairs of S/P transducers 204 in IFFT unit is carried out IFFT and is calculated.

P/S transducer 206 is changed back serial signal with the output of IFFT unit 205.CP inserter 207 has the function that is used for to the additional CP of output signal of P/S transducer 206.

Fig. 3 A to 3C is the figure of a plurality of examples that the normalization precoder of Fig. 2 is shown.Fig. 3 A is the figure that the normalization precoder that wherein uses Hadamard transform is shown.

With reference to Fig. 3 A, said normalization precoder comprises symbolic solution multiplexer (DEMUX) 311, Walsh (Walsh) function capping unit 312 and Walsh summer 313.

Symbol DEMUX 311 will convert parallel signal into from the serial signal that the modulator 202 of Fig. 2 is exported.Walsh function capping unit 312 is carried out and is utilized the walsh code with predetermined length each modulation symbol from symbol DEMUX 311 outputs to be carried out the processing of Walsh covering or spread spectrum.Walsh summer 313 is carried out the processing with the output of walsh function capping unit 312 output of each walsh function spread spectrum (that is, by) summation.

Fig. 3 B is the figure that the normalization precoder that wherein uses fast Fourier transform (FFT) is shown.

With reference to Fig. 3 B, said normalization precoder comprises symbol DEMUX 321, FFT unit 322 and P/S transducer 323.

Symbol DEMUX 321 will convert parallel signal into from the serial signal that the modulator 202 of Fig. 2 is exported.The FFT conversion is carried out in the output of the 322 couples of symbol DEMUX 321 in FFT unit.P/S transducer 323 will be from the FFT unit parallel signal of 322 outputs convert serial signal into.

Fig. 3 C is the figure that the normalization precoder that wherein uses fast frequency-hopped (FFH) is shown.

With reference to Fig. 3 C, said normalization precoder comprises symbol DEMUX 331, FFH linear processor 332 and P/S transducer 333.

Symbol DEMUX 331 will convert parallel signal into from the serial signal that the modulator 202 of Fig. 2 is exported.The FFH linear transformation is carried out in the output of 332 couples of symbol DEMUX 331 of FFH linear processor.FFH is the technology of the different subcarrier of each OFDM sampling mapping.P/S transducer 333 will convert serial signal into from the parallel signal of FFH linear processor 332 outputs.

In aforesaid traditional normalization precoding OFDM multiplexing scheme, the hadamard precoding OFDM scheme of Fig. 3 A will be called orthogonal frequency code division multiplexing (OFCDM) scheme, and the FFT precoding OFDM of Fig. 3 B will be called FFT spread spectrum OFDM (FFT-S-OFDM) scheme.In addition, the FFH precoding OFDM scheme of Fig. 3 C will be called fast frequency-hopped-OFDM (FFH-OFDM) scheme.

Fig. 4 is the figure of brief description of the notion of the general FFH that introduces among Fig. 3 C.

With reference to Fig. 4, will be to the FFT size of M=4, an OFDM symbol time through more existing frequency hopping and FFH technical descriptioon FFH technology.

In Fig. 4, reference numerals 401 expressions are used for the 4-OFDM sampling time is carried out the multi-carrier modulation device of existing every symbol frequency hopping.Reference numerals 405 to 408 expression FFH multi-carrier modulation devices.

In the existing frequency hopping shown in Fig. 4 left side, to the 4-OFDM sampling time, the input data are identical, and will export signal in each sampling time and export one by one.Because it is mapping fixed joint carrier wave in the existing frequency hopping 1-OFDM symbol time, so identical by the piece of reference numerals 401 to 404 expressions for the 4-OFDM sampling time.

Yet, in the FFH technology shown in Fig. 4 the right, utilize the M:M change over switch to change the mapping between subchannel data and the actual subcarrier in each sampling time.The subcarrier that first subchannel of being represented by reference numerals 405 is mapped to is shone upon with order [1 42 3]; The subcarrier that second subchannel of being represented by reference numerals 406 is mapped to is shone upon with order [4 31 2]; The subcarrier that is mapped to by the 3rd subchannel of reference numerals 407 expression is shone upon with order [2 13 4], and by the fourth officer channel Mapping of reference numerals 408 expressions to subcarrier shone upon with order [3 24 1].This mapping pattern is called the frequency hopping style of each subchannel.

As stated, with normalization precoding OFDM compared with techniques, the OFDM technology demonstrates higher performance at low encoding rate.Yet with the OFDM compared with techniques, normalization precoding OFDM technology demonstrates higher performance at very high encoding rate (such as, 4/5 encoding rate).No matter these characteristics, common GSM is non-use with a good grace OFDM and normalization precoding OFDM technological one of them be used for packet data transport channel.

Thereby, need a kind ofly use improved adaptive data multiplexing method and transmission/receiving system in the technological OFDMA system of OFDM and normalization precoding OFDM.

Summary of the invention

An aspect of example embodiment of the present invention is to overcome the above problems at least and/or shortcoming and following advantage is provided at least.Thereby; An aspect of example embodiment of the present invention provides a kind of transmission/method of reseptance and device; Its according to environment self-adaption utilize the two of OFDM and normalization precoding OFDM technology rather than only one of them, to improve the receptivity in the transmission/receiving block data in based on the wireless communication system of OFDM.

An aspect according to example embodiment of the present invention; Adaptive data multiplexing sending method in the base station of a kind of OFDM (OFDMA) system is provided; Packet communication is carried out in the terminal in the said OFDMA system in the covering of base station; Grouped data is sent to the terminal in the base station, and this method comprises: collection is used for the information that dispatching office needs; Use collected information and executing scheduling; The encoding rate and the predetermined threshold that will send to the data at least one terminal of confirming according to scheduling result compare; Select suitable multiplexing scheme according to comparative result; And use selected multiplexing scheme to send grouped data.Wherein said multiplexing scheme comprises: the normalization precoding OFDM of selecting (OFDM), if the encoding rate of said data is lower than said threshold value; And OFDM, if the encoding rate of said data is higher than said threshold value.

Another aspect according to example embodiment of the present invention; Adaptive data multiplexing sending method in the base station of a kind of OFDM (OFDMA) system is provided; Packet communication is carried out in the terminal in the said OFDMA system in the covering of base station; Grouped data is sent to the terminal in the base station, and this method comprises: collection is used for the information that dispatching office needs; Use collected information and executing scheduling; Obtain and the corresponding effective signal-to-noise ratio (SNR) that divides into groups according to the transmission at least one selected terminal of scheduling result to normalization precoding OFDM (OFDM) and OFDM; Effective SNR of normalization precoding OFDM and effective SNR of OFDM are compared; Select to be fit to the multiplexing scheme at selected terminal according to comparative result; And use selected multiplexing scheme to send grouped data.

Another aspect according to example embodiment of the present invention; Adaptive data multiplexing method of reseptance in the terminal of a kind of OFDM (OFDMA) system is provided; Packet communication is carried out in the terminal in the said OFDMA system in the covering of base station; Grouped data is sent to the terminal in the base station, and this method comprises: the grouped data that determines whether to receive said terminal; If received the grouped data at said terminal, then search for the employed multiplexing scheme of grouped data at said terminal; And use the multiplexing scheme demultiplexing grouped data search; Wherein, In the base station, select multiplexing scheme based on the encoding rate of the data that will send to the terminal and the comparative result between the threshold value or based on the comparative result between effective SNR of the effective SNR of normalization precoding OFDM and OFDM.

Another aspect according to example embodiment of the present invention; The base station apparatus of a kind of OFDM (OFDMA) system is provided; Packet communication is carried out in the terminal in the said OFDMA system in the covering of base station; The base station is sent grouped data through adaptive data multiplexing to the terminal, and this device comprises: the normalization converter unit is used in frequency domain the modulation symbol that will send being carried out the normalization conversion; Switch unit is used to switch to said normalization converter unit; And controller; Be used for relatively will sending to effective SNR and the effective SNR of OFDM of normalization precoding OFDM at encoding rate and threshold value or more selected terminal of the data at least one selected terminal; Select to be suitable for the multiplexing scheme at selected terminal according to comparative result, determine whether to switch said switch unit according to selected multiplexing scheme.

Another aspect according to example embodiment of the present invention; The terminal installation of a kind of OFDM (OFDMA) system is provided; Packet communication is carried out in the terminal in the said OFDMA system in the covering of base station; The base station is sent grouped data through adaptive data multiplexing to the terminal, and this device comprises: contrary normalization converter unit is used in frequency domain the modulation symbol that receives being carried out contrary normalization conversion; And controller; If be used for the grouped data that the terminal is confirmed to have received in the terminal; Then search is used for end packet data multiplexing scheme, determines whether to launch said contrary normalization converter unit according to the multiplexing scheme of selecting, wherein; In the base station, select multiplexing scheme based on the encoding rate of the data that will send to the terminal and the comparative result between the threshold value or based on the comparative result between effective SNR of the effective SNR of normalization precoding OFDM and OFDM.

According to another aspect of example embodiment of the present invention, a kind of OFDM (OFDMA) system is provided, wherein packet communication is carried out in the terminal in the covering of base station; The base station is sent grouped data through adaptive data multiplexing to the terminal; Collection is used for the information that dispatching office needs; Use collected information and executing scheduling; The encoding rate and the predetermined threshold that will send to the data at least one terminal of confirming according to scheduling result compare, and select suitable multiplexing scheme according to comparative result, and use selected multiplexing scheme to send grouped data; And the terminal determines whether to receive its grouped data, if received its grouped data, then searches for the employed multiplexing scheme of grouped data of himself, and uses the multiplexing scheme demultiplexing grouped data that searches.Wherein said multiplexing scheme comprise at least following one of them: the normalization precoding OFDM of selecting (OFDM), if the encoding rate of said data is lower than said threshold value; And OFDM, if the encoding rate of said data is higher than said threshold value.

According to another aspect of example embodiment of the present invention, a kind of OFDM (OFDMA) system is provided, wherein packet communication is carried out in the terminal in the covering of base station; The base station is sent grouped data through adaptive data multiplexing to the terminal; Collection is used for the information that dispatching office needs; Use collected information and executing scheduling; Obtain and the corresponding effective signal-to-noise ratio (SNR) that divides into groups according to the transmission at least one definite terminal of scheduling result to normalization precoding OFDM (OFDM) and OFDM; Effective SNR of normalization precoding OFDM and effective SNR of OFDM are compared, select to be fit to the multiplexing scheme at this terminal, and use selected multiplexing scheme to send grouped data according to comparative result; And the terminal determines whether to receive its grouped data, if received its grouped data, then searches for the employed multiplexing scheme of grouped data of himself, and uses the multiplexing scheme demultiplexing grouped data that searches.

Through disclose the detailed description of example embodiment of the present invention below in conjunction with accompanying drawing, other purpose of the present invention, advantage and notable feature will become obvious to those skilled in the art.

Description of drawings

Through the detailed description below in conjunction with accompanying drawing, above and other purpose, characteristic and the advantage of some example embodiment of the present invention will become more obvious, wherein:

Fig. 1 is the block diagram that the structure of the transmitter that is used for general ofdm system is shown;

Fig. 2 is the block diagram that the structure of general normalization precoding OFDM transmitter is shown;

Fig. 3 A is the figure that the normalization precoder that wherein uses Hadamard transform is shown;

Fig. 3 B is the figure that the normalization precoder that wherein uses fast Fourier transform (FFT) is shown;

Fig. 3 C is the figure that the normalization precoder that wherein uses fast frequency-hopped (FFH) is shown;

Fig. 4 is the figure of brief description of the notion of the general FFH that introduces among Fig. 3 C;

Fig. 5 illustrates the OFDM of encoding rate=1/4 for transmission block and the performance comparison result's between the OFCDM figure;

Fig. 6 illustrates the OFDM of encoding rate=1/2 for transmission block and the performance comparison result's between the OFCDM figure;

Fig. 7 illustrates the OFDM of encoding rate=4/5 for transmission block and the performance comparison result's between the OFCDM figure;

Fig. 8 and 9 is the figure based on the method in the wireless communication system of OFDM that illustrate according to example embodiment of the present invention; Wherein transmitter is selected multiplexing scheme based on predetermined criterion at every turn adaptively when sending Packet Data Channel, and uses selected multiplexing scheme to send and divide into groups;

Figure 10 is the figure based on the structure of the transmitter of the self adaptation multiplexing method of Fig. 8 or 9 that illustrates according to example embodiment of the present invention;

Figure 11 is the figure that illustrates according to the method for example embodiment of the present invention, and wherein receiver uses the self adaptation multiplexing method that proposes to receive grouping; And

Figure 12 is the figure that illustrates according to the structure of the receiver of example embodiment of the present invention.

Embodiment

The entity such as detailed structure and parts that defines in the specification provides and is used to help the complete understanding embodiments of the invention.Thereby those of ordinary skills will be appreciated that, can carry out various changes and modification to the embodiments described herein and do not deviate from scope of the present invention and spirit.Equally, for knowing and for purpose of brevity, having omitted the explanation of known function and structure.

The term of broad sense " normalization precoding OFDM " comprises that OFCDM, FFT-S-OFDM and FFH-OFDM's is whole.Though what Fig. 5 to 7 showed is the comparing data between OFDM and the OFCDM, OFCDM, FFT-S-OFDM and FFH-OFDM all have identical characteristic.Thereby, can regard Fig. 5 to 7 as between OFDM and the normalization precoding OFDM emulated data.

The relative performance of aforementioned two kinds of technology (that is, OFDM and normalization precoding OFDM) is not constant, but can change according to several kinds of factors.Key factor in these several kinds of factors can comprise the encoding rate of data transmission block and the frequency selectivity of channel.Thereby, with reference to Fig. 5 to 7, will the performance comparison result between OFDM and the OFCDM be described with regard to encoding rate and selectivity of channel frequency now.

Fig. 5 is the performance comparison result's between OFDM and the OFCDM that encoding rate=1/4 for transmission block is shown (among Fig. 5 to 7 note do ' MC CDM ') figure.Among Fig. 5 to 7, gain paths such as ' EG ' expression, and ' UEG ' expression does not wait gain path.In the curve chart, the X axle is represented potential energy/overall noise (Eb/Nt), and the Y axle is represented packet-error-rate (PER).

Among Fig. 5, OFDM is superior to OFCDM (MC CDM) in encoding rate=1/4 place's performance of transmission block.Equally, the performance difference level changes according to the variation in the frequency selectivity (that is the variation in the number of paths).

Fig. 6 illustrates the OFDM of encoding rate=1/2 for transmission block and the performance comparison result's between the OFCDM figure.

Among Fig. 6, OFDM is superior to OFCDM (MC CDM) in encoding rate=1/2 place's performance of transmission block.Equally, the performance difference level changes according to the variation in the frequency selectivity (that is the variation in the number of paths).

Fig. 7 illustrates the OFDM of encoding rate=4/5 for transmission block and the performance comparison result's between the OFCDM figure.

Among Fig. 7, OFDM is superior to OFCDM in encoding rate=4/5 place's performance of transmission block.Equally, the performance difference level changes according to the variation in the frequency selectivity (that is the variation in the number of paths).

Fig. 8 and 9 is the figure based on the method in the wireless communication system of OFDM that illustrate according to example embodiment of the present invention; Wherein transmitter is selected multiplexing scheme based on predetermined criterion at every turn adaptively when sending Packet Data Channel, and uses selected multiplexing scheme to send and divide into groups.

In other words, Fig. 8 and 9 is the methods of sending forward data from the base station to the terminal that illustrate according to example embodiment of the present invention.According to the base station select adaptively multiplexing scheme based on criterion, can said forward data sending method be divided into the method for Fig. 8 and 9.The method of Fig. 8 will at first be described below.

With reference to Fig. 8, in step 801, the scheduler of packet sender is collected and is used for the information that dispatching office needs.The information that being used for dispatching office needs can comprise professional service quality (QoS) grade of each user's communications, each user's current channel condition and each user's the amount of current transmission communication service usually.

In step 802, the scheduler of packet sender is operation dispatching after collection is used for information that dispatching office needs.In scheduling process, scheduler is confirmed the user's that it will send with a data rate in the corresponding time grouped data.User for selecting can select one or more user according to system status.Specified data speed means that how long confirm will be to send many lot of data.In this process, general GSM is confirmed modulating rule (for example, QPSK, 8PSK, 16QAM or the like) and encoding rate with each individual consumer's data rate.

After confirming scheduling, confirm to be used to send the multiplexing scheme of the grouped data of selected user in to 805 in step 803.The core that can step 803 be regarded as example embodiment of the present invention to the operation in 805.In step 803, packet sender is confirmed as the result of scheduling and definite encoding rate that is used for grouped data is higher than or be lower than predetermined threshold T_r.Select the reason of multiplexing scheme to be because the performance of OFDM and normalization precoding OFDM is responsive to encoding rate according to encoding rate, shown in the simulation result of Fig. 5 and 7.Thereby some example embodiment of the present invention is based in the packet sender threshold value of predetermined encoding rate and selects multiplexing scheme.

If confirm that in step 803 encoding rate is not higher than T_r, then packet sender confirms that OFDM is as multiplexing scheme in step 804.On the other hand, packet sender confirms that normalization precoding OFDM is as multiplexing scheme in step 805.After this, in operation 806, packet sender is sent grouped data according to the multiplexing scheme of confirming in to 805 in step 803.

Fig. 9 illustrates the figure that comes to confirm adaptively the process of multiplexing scheme according to the use of example embodiment of the present invention another criterion different with Fig. 8.

With reference to Fig. 9, in step 901, the scheduler of packet sender is collected and is used for the information that dispatching office needs.The information that being used for dispatching office needs can comprise the professional QoS grade of each user's communications, each user's current channel condition and each user's the amount of current transmission communication service usually.

In step 902, the scheduler of packet sender is operation dispatching after collection is used for information that dispatching office needs.In scheduling process, scheduler is confirmed the user's that it will send with a data rate in the corresponding time grouped data.User for selecting can select at least one user according to system status.Specified data speed means that how long confirm will be to send many lot of data.In this process, general GSM is confirmed modulating rule (for example, QPSK, 8PSK, 16QAM or the like), encoding rate and each individual consumer's data rate.

After confirming scheduling, confirm to be used to send the multiplexing scheme of the grouped data of selected user in to 906 in step 903.Can regard step 903 to the operation in 906 as core of the present invention.Be used for confirming adaptively that according to another of example embodiment of the present invention criterion of multiplexing scheme comprises effective signal to noise ratio (snr).Also promptly, the method for proposition is confirming aspect effective SNR of the current channel of selected user that OFDM is higher than or is lower than normalization precoding OFDM, and then selects to have the multiplexing scheme of higher effective SNR.

Effective SNR of OFDM will remember and make SNR _Eff_ OFDM, and effective SNR of normalization precoding OFDM will remember and make SNR _Eff_ Unitary.Usually, can in each terminal, measure each user's wireless channel, so SNR can be known in said terminal _Eff_ OFDM and SNR _Eff_ Unitary.Thereby, know SNR in order to allow the base station _Eff_ OFDM and SNR _Eff_ Unitary has a kind of possible method, and wherein each terminal is with SNR _Eff_ OFDM and SNR _EffThe two feeds back to the base station _ Unitary.Also have a kind of possible method in addition, wherein each terminal is with SNR _Eff_ OFDM and SNR _EffOne of them feeds back to the base station with the information about its first-selected multiplexing scheme _ Unitary.

The base station obtains the SNR at each terminal in step 903 and the said method _Eff_ OFDM and SNR _EffThe process of _ Unitary is corresponding.To introduce as an example below and be used to calculate SNR _Eff_ OFDM and SNR _EffThe conventional method of _ Unitary.

${\mathrm{SNR}}_{\mathrm{eff}}\_\mathrm{Unitary}=\frac{{\mathrm{\λ}}_T^2}{{\mathrm{N\λ}}_T-.{\mathrm{\λ}}_T^2},$

Wherein ${\mathrm{\λ}}_T=\underset{k=1}{\overset{N}{\mathrm{\Σ}}}{\mathrm{\λ}}_k=\underset{k=1}{\overset{N}{\mathrm{\Σ}}}\frac{{\mathrm{\γ}}_0\·{\left|g_k\right|}^2}{{\mathrm{\γ}}_0\·{|g_k|}^2+1}\·\·\·\·\·\·\·\·\·\·\·\·\·\·\·\·\left(1\right)$

And γ ₀| g _k| ²SNR equality (1) expression of=the k subcarrier is used to obtain SNR _EffThe conventional method of _ Unitary.

SNR _eff_OFDM＝C ^-1(R _sum)，

Wherein $R_{\mathrm{Sum}}=\frac{1}{N_{\mathrm{Data}}}\underset{n,k}{\mathrm{\Σ}}C\left(\mathrm{SNR}\right[k\left]\right)\·\·\·\·\·\·\·\·\·\·\·\·\left(2\right)$

Equality (2) expression is used to obtain SNR _EffThe conventional method of _ OFDM.In the equality (2), N _DataRepresent to be used in the OFDM symbol to send the quantity of the subcarrier of data, SNR [k] representes the SNR of each subcarrier, C (SNR [k]) expression AWGN capacity formula, and C ^-1(R _Sum) expression C (SNR [k]) inverse function.

${\mathrm{SNR}}_{\mathrm{eff}}=-\mathrm{\β}\ln \left(\frac{1}{N_u}\underset{k=1}{\overset{N_u}{\mathrm{\Σ}}}{e}^{-\frac{{\mathrm{\γ}}_k}{\mathrm{\β}}}\right)\·\·\·\·\·\·\·\·\·\·\·\·\·\left(3\right)$

Equality (3) expression is used to obtain SNR _EffThe another kind of conventional method of _ OFDM.In the equality (3), β is a constant, N _uThe sum of vice carrier wave, and γ _kThe SNR of vice carrier wave #k.In step 904, packet sender obtains SNR _Eff_ OFDM and SNR _Eff_ Unitary also compares SNR _Eff_ OFDM and SNR _EffThe level of _ Unitary.

If in step 904, confirm SNR _Eff_ Unitary is higher than SNR _Eff_ OFDM, then packet sender selects normalization precoding OFDM as multiplexing scheme in step 906.Otherwise packet sender selects OFDM as multiplexing scheme in step 905.After this, in step 907, packet sender is sent grouped data according to selected multiplexing scheme.

Figure 10 is the figure based on the structure of the transmitter of the self adaptation multiplexing method of Fig. 8 or 9 that illustrates according to example embodiment of the present invention.

With reference to Figure 10, said transmitter based on the self adaptation multiplexing method comprises channel encoder 1001, modulator 1002, normalization converter unit 1003, switch unit 1004, controller 1005, S/P transducer 1006, IFFT unit 1007, P/S transducer 1008 and CP inserter 1009.

1001 pairs of input information bit streams of channel encoder are carried out chnnel coding.Usually, use convolution coder, turbo encoder or LDPC encoder as channel encoder 1001.QPSK, 8PSK or 16QAM modulation are carried out in the output of 1002 pairs of channel encoders 1001 of modulator.Though not shown among Figure 10, those skilled in the art obviously can know, can between parts 1001 and 1002, add the rate-matched unit that is used to carry out repetition and perforation.

Switch unit 1004 is carried out switching under the control of controller 1005, with use OFDM and normalization precoding OFDM one of them as multiplexing scheme.Controller 1005 is controlled switch unit 1004 in the process of Fig. 8 or 9.If switch unit 1004 switches to normalization converter unit 1003 under the control of controller 1005, then launch the normalization precoder.Also promptly, utilize the OFCDM, FFT-S-OFDM or the FFH-OFDM that describe with reference to Fig. 2 to send data.

Normalization converter unit 1003 is equal to any the normalization precoder shown in Fig. 3 A to 3C with operating in structure.If switch unit 1004 switches to S/P transducer 1006 under the control of controller 1005, then transmitter is not launched normalization converter unit 1003.

S/P transducer 1006 has the function that is used for serial input signals is converted into parallel signal.The output of the 1007 pairs of S/P transducers 1006 in IFFT unit is carried out IFFT and is calculated.P/S transducer 1008 converts the also line output of IFFT unit 1007 into serial signal.CP inserter 1009 has the function that is used for to the additional CP of output signal of P/S transducer 1008.

Though among Figure 10 and not shown, according to the intended size of the output of S/P transducer 1006, the size of the matrix corresponding with normalization converter unit 1003 is variable.In addition, because the size variable of said matrix can use a plurality of normalization precoders.Yet transmitter is not to comprise a plurality of normalization precoders, can utilize a normalization precoder to carry out the calculating that iterates yet.

For example, if the output of S/P transducer 1006 is of a size of 16 (quantity that means the subcarrier of distributing to transmitter is 16), mean that then the input of S/P transducer 1006 is of a size of 16.Wherein, can use the pre-encoder matrix (or the pre-encoder matrix that utilizes a size-4 is done four calculating) of the pre-encoder matrix of a size-16, the pre-encoder matrix of two sizes-8 (or the pre-encoder matrix that utilizes a size-8 is done twice calculating), four sizes-4 or the pre-encoder matrix (or the pre-encoder matrix that utilizes a size-2 is done eight calculating) of eight sizes-2 to be used for normalization converter unit 1003.

Simultaneously, some example embodiment of the present invention is not must be confined to forward send.The method that proposes can be applied to reverse transmission equally, that is, send from the data of terminal to base station.Yet, in most systems, because the operating main body of scheduling is the base station, so after with the direct operation dispatching of the mode of Fig. 8 or 9, the terminal receives from the base station and is used for reverse schedule information of sending, rather than uses said self adaptation multiplexing method.After this, send time of the permission of data at transmitter, transmitter is selected multiplexing scheme with slightly different mode according to criterion same as described above adaptively.

Figure 11 is the figure that illustrates according to the method for example embodiment of the present invention, and wherein receiver uses the self adaptation multiplexing method that proposes to receive grouping.

Though will divide into groups to send the method for describing Figure 11 with reference to the forward from the base station to the terminal, said method can be applied to reverse packet equally and send.

With reference to Figure 11, in step 1101, the terminal determines whether to have received the grouping of himself continuously.Corresponding operating in operation in the step 1101 and the common block data system is equal to.Also promptly, in this process, the terminal is kept watch on along the packet data control channel of direction transmission continuously and is determined whether any grouping of distributing to this terminal oneself.

If definite grouping that has received this terminal self in step 1101, the then process of terminal execution receiving block data channel in step 1102.At this moment, employed multiplexing scheme (OFDM and normalization precoding OFDM one of them) should search packet be sent at the terminal.

For the operation of performing step 1102, two kinds of possible methods are arranged.In first kind of possible method, the base station provides the information of the employed multiplexing scheme of indication to the terminal through packet data control channel.

In the another kind of possible method, between sender and recipient, define employed multiplexing scheme in advance, be centrally located in specific encoding rate.Example embodiment person, in a single day receiver has known encoding rate, just can confirm that transmitter has used any multiplexing scheme when sending grouping.For example, be defined in advance and be less than or equal to 1/2 encoding rate place and use OFDM, and use OFCDM at the encoding rate place that is higher than 1/2.

In step 1103, the terminal will send to its Packet Data Channel demodulation according to the multiplexing scheme that in step 1102, obtains.

Figure 12 is the figure that illustrates according to the structure of the receiver of example embodiment of the present invention.

With reference to Figure 12, said receiver comprises CP canceller 1201, S/P transducer 1202, fast Fourier transform (FFT) unit 1203, P/S transducer 1204, contrary normalization converter unit 1205, controller 1206, demodulator 1207 and channel decoder 1208.

CP canceller 1201 is deleted CP from the signal that receives.The conversion of signals that S/P transducer 1202 will be deleted the reception of CP is a parallel signal, and said parallel signal is outputed to FFT unit 1203.P/S transducer 1204 converts the output of FFT unit 1203 into serial signal.Contrary normalization converter unit 1205 is the pieces that are used to carry out contrary normalization conversion.Contrary normalization converter unit 1205 confirms to launch the still contrary normalization converter of forbidding under the control of controller 1206.To be input to demodulator 1207 against the output of normalization converter unit 1205, and the output of demodulator 1207 will be input to channel decoder 1208.Channel decoder 1208 obtains final information through the channel-decoding process.

Though it is also not shown among Figure 12; With Figure 10 in similarly in the method, according to the intended size of the output of P/S transducer 1204, the size of the matrix corresponding with contrary normalization converter unit 1205 is variable; Because the size variable of said matrix can use a plurality of normalization precoders.Yet receiver is not to comprise a plurality of normalization precoders, can utilize a normalization precoder to carry out the calculating that iterates yet.For example; If the output of supposition P/S transducer 1204 is of a size of 16, then can use the pre-encoder matrix (or the pre-encoder matrix that utilizes a size-4 is done four calculating) of the pre-encoder matrix of a size-16, the pre-encoder matrix of two sizes-8 (or the pre-encoder matrix that utilizes a size-8 is done twice calculating), four sizes-4 or the pre-encoder matrix (or the pre-encoder matrix that utilizes a size-2 is done eight calculating) of eight sizes-2 to be used for contrary normalization converter unit 1205.

The self adaptation multiplexing method that proposes among the present invention also can use in the system that adopts mixed automatic retransmission request (HARQ).Usually, in the grouping process of transmitting in the system that adopts HARQ, under many situation, the encoding rate that is used for initialization is higher.Thereby if receiver uses OFDM to be used for the HARQ based on normalization precoding OFDM during initialization according to the rule that proposes, then it can improve receptivity expeditiously.In addition, can be used for definite multiplexing rule through using according to effectively SNR rather than the initialization of encoding rate adaptively modifying and multiplexing scheme in redispatching.

In order to simplify the HARQ operation, a kind of possible method is arranged, wherein in a single day in initialization, confirmed multiplexing scheme based on encoding rate or effective SNR, just can use with the identical multiplexing scheme of in initialization, confirming of scheme to be used to redispatch.As stated; Those skilled in the art obviously can know; The self adaptation multiplexing method that proposes in the example embodiment of the present invention can be used for HARQ; And even can use that two criterions (that is, encoding rate with effectively SNR) of the receptivity of the grouping that helps to improve transmission wherein select for other purpose one of confirm multiplexing scheme.

Can know that from above description in the communication system of use based on the multiple access scheme of OFDM, some example embodiment of the present invention can use the self adaptation multiplexing method to improve the receptivity of the wireless packet data of transmission.

Though showed and described the present invention with reference to its some embodiment; But it will be appreciated by those skilled in the art that and to make various changes and not deviate from the spirit and scope of the present invention that limit appended claims and equivalent thereof from form and details therein.

Claims (12)

1. the adaptive data multiplexing sending method in the base station of an OFDM OFDMA system, packet communication is carried out in the terminal in the said OFDMA system in the covering of base station, and grouped data is sent to the terminal in the base station, this method comprises:

Collection is used for the information that dispatching office needs;

Use collected information and executing scheduling;

The encoding rate and the threshold value that will send to the data at least one terminal of confirming according to scheduling result compare;

Select suitable multiplexing scheme according to comparative result; And

Use selected multiplexing scheme to send grouped data,

Wherein said multiplexing scheme comprises: the normalization precoding OFDM of selecting (OFDM), if the encoding rate of said data is lower than said threshold value; And OFDM, if the encoding rate of said data is higher than said threshold value.

2. the adaptive data multiplexing sending method in the base station of an OFDM OFDMA system, packet communication is carried out in the terminal in the said OFDMA system in the covering of base station, and grouped data is sent to the terminal in the base station, this method comprises:

Collection is used for the information that dispatching office needs;

Use collected information and executing scheduling;

Obtain and the corresponding effective signal-to-noise ratio (SNR) that divides into groups according to the transmission at least one selected terminal of scheduling result to normalization precoding OFDM (OFDM) and OFDM;

Effective SNR of normalization precoding OFDM and effective SNR of OFDM are compared;

Select to be fit to the multiplexing scheme at selected terminal according to comparative result; And

Use selected multiplexing scheme to send grouped data.

3. adaptive data multiplexing sending method as claimed in claim 2, wherein said multiplexing scheme comprises: the normalization precoding OFDM that selects, if effective SNR of normalization precoding OFDM is higher than effective SNR of OFDM; And OFDM, if effective SNR of normalization precoding OFDM is lower than effective SNR of OFDM.

4. the adaptive data multiplexing method of reseptance in the terminal of an OFDM OEDMA system, packet communication is carried out in the terminal in the said OFDMA system in the covering of base station, and grouped data is sent to the terminal in the base station, this method comprises:

Determine whether to receive the grouped data at terminal;

If received the grouped data at terminal, the employed multiplexing scheme of the grouped data of search terminal then; And

The multiplexing scheme demultiplexing grouped data that use searches,

Wherein, in the base station, select multiplexing scheme based on the encoding rate of the data that will send to the terminal and the comparative result between the threshold value or based on the comparative result between effective SNR of the effective SNR of normalization precoding OFDM and OFDM.

5. adaptive data multiplexing method of reseptance as claimed in claim 4, wherein said multiplexing scheme comprise normalization precoding OFDM (OFDM) and OFDM at least one of them.

6. the base station apparatus of an OFDM OFDMA system, packet communication is carried out in the terminal in the said OFDMA system in the covering of base station, and the base station is sent grouped data through adaptive data multiplexing to the terminal, this device comprises:

The normalization converter unit is used in frequency domain the modulation symbol that will send being carried out the normalization conversion;

Switch unit is used to switch to said normalization converter unit; And

Controller; Be used for relatively will sending to effective SNR and the effective SNR of OFDM of normalization precoding OFDM at encoding rate and threshold value or more selected terminal of the data at least one selected terminal; Select to be suitable for the multiplexing scheme at selected terminal according to comparative result, determine whether to switch said switch unit according to selected multiplexing scheme.

7. base station apparatus as claimed in claim 6, wherein said multiplexing scheme comprise normalization precoding OFDM (OFDM) and OFDM at least one of them.

8. the terminal installation of an OFDM OFDMA system, packet communication is carried out in the terminal in the said OFDMA system in the covering of base station, and the base station is sent grouped data through adaptive data multiplexing to the terminal, this device comprises:

Contrary normalization converter unit is used in frequency domain the modulation symbol that receives being carried out contrary normalization conversion; And

Controller, if be used for the grouped data that the terminal is confirmed to have received in the terminal, then search is used for end packet data multiplexing scheme, determines whether to launch said contrary normalization converter unit according to the multiplexing scheme of selecting,

Wherein, in the base station, select multiplexing scheme based on the encoding rate of the data that will send to the terminal and the comparative result between the threshold value or based on the comparative result between effective SNR of the effective SNR of normalization precoding OFDM and OFDM.

9. terminal installation as claimed in claim 8, wherein said multiplexing scheme comprise normalization precoding OFDM (OFDM) and OFDM at least one of them.

10. OFDM OFDMA system comprises:

The base station; Be used to collect the information that is used for the dispatching office need; Use collected information and executing scheduling; The encoding rate and the threshold value that will send to the data at least one terminal of confirming according to scheduling result compare, and select suitable multiplexing scheme according to comparative result, and use selected multiplexing scheme to send grouped data; And

The terminal; Be used in the covering of base station, carrying out packet communication, wherein said base station is sent grouped data through adaptive data multiplexing to the terminal, and said terminal determines whether to receive its grouped data; If received its grouped data; Then search for the employed multiplexing scheme of grouped data of himself, and use the said grouped data of multiplexing scheme demultiplexing that searches

Wherein said multiplexing scheme comprise at least following one of them: the normalization precoding OFDM of selecting (OFDM), if the encoding rate of said data is lower than said threshold value; And OFDM, if the encoding rate of said data is higher than said threshold value.

11. an OFDM OFDMA system comprises:

The base station; Be used to collect the information that is used for the dispatching office need; Use the scheduling of collected information and executing, obtain and the corresponding effective signal-to-noise ratio (SNR) of transmission grouping, effective SNR of normalization precoding OFDM and effective SNR of OFDM are compared according at least one definite terminal of scheduling result among normalization precoding OFDM (OFDM) and the OFDM each; Select to be fit to the multiplexing scheme at this terminal according to comparative result, and use selected multiplexing scheme to send grouped data; And

The terminal; Be used in the covering of base station, carrying out packet communication; Wherein said base station is sent grouped data through adaptive data multiplexing to the terminal, and said terminal determines whether to receive its grouped data, if received its grouped data; Then search for the employed multiplexing scheme of grouped data of himself, and use the said grouped data of multiplexing scheme demultiplexing that searches.

12. OFDMA as claimed in claim 11 system, wherein said multiplexing scheme comprise at least following one of them: the normalization precoding OFDM that selects, if effective SNR of normalization precoding OFDM is higher than effective SNR of OFDM; And OFDM, if effective SNR of normalization precoding OFDM is lower than effective SNR of OFDM.

Images