CN101222675B - Method for transmitting and receiving multimedia broadcast multicast service in TDD mode - Google Patents

Abstract

The invention discloses a method for transmitting and receiving multimedia broadcast and multicast services under TTD; all the cells in each base station form exactly the same MBMS symbol level data for spreading spectrum and scrambling, thereby forming baseband signals which are to be treated with transmitting in each cell; when the signals are transmitted, each cell uses different basic training sequences; according to system information, user equipment UE carries out channel evaluation to obtain the channel impulse response of each cell, and respectively calculates a system matrix corresponding to each cell and combines the system matrixs to a compound system matrix; an estimated MBMS service symbol level data is obtained by combining, detecting and processing the received baseband data and operated by demodulation and coding, thereby obtaining the original data of the MBMS service. The invention reduces the service interference, provides diversity and amplification and improves the transmission performance of the MBMS service.

Description

Multimedia broadcast multicast service in TDD mode emission and the method that receives

Technical field

The present invention relates to the MBMS (multimedia broadcast multi-broadcasting business in a kind of wireless communication system, Multimedia Broadcast/Multicast Service) emission and reception technique, relate in particular to MBMS emission and the method that receives under TDD (time division duplex, the Time Division Duplex) communication mode.

Background technology

The MBMS business is a kind of high speed one way traffic with the transmission of broadcast or multicast form, and it can effectively transmit high-speed multimedia data to a plurality of users simultaneously.MBMS requires this professional user of any activation in the whole sub-district can receive the content that this business is sent out.Because the point-to-multipoint mode (PtM) among the MBMS is launched with broadcast mode, up do not have a feedback information, the base station can't obtain each user's channel information, so common Poewr control method can't be implemented, downlink broadcast is launched with constant power within a certain period of time usually.

Simultaneously, in the TDD wireless communication system, because the data rate of MBMS business is than higher, so the code channel number that MBMS business takies is more than the code channel number of P-CCPCH, if time slot power is identical, the solid size road transmitting power of the S-CCPCH of MBMS business can be littler than the solid size road transmitting power of P-CCPCH, so, be broadcast channel equally, the coverage of the S-CCPCH channel of carrying MBMS business can be little more a lot of than the coverage of P-CCPCH.

If utilize the method for the transmitting power that increases the MBMS business to remedy above deficiency, so in network, except having increased the signal power of this sub-district, the also corresponding increase of signal power of adjacent sub-district, so, the interference signal of user side increases simultaneously with effective power, and the signal interference ratio of user's received signal does not improve.In this case, be in the middle user in a plurality of sub-districts and can't from multiple interference, obtain correct signal.

Having mentioned a kind of neighbor cell in the patent No. is the patent of WO2005048484 divides time slot to send the method for same MBMS business, can carry out the laggard line data of receiving demodulation to these data at user equipment (UE) like this and merge, can provide macro diversity for the reception of MBMS business like this.But this method sends because of minute time slot, thereby can take too much time interval resource, and cell management can more complicated.

In sum, should find and a kind ofly can avoid minizone MBMS traffic interference, can receive the method that transmits and receives that the MBMS business provides gain for UE again.

Summary of the invention

Technical problem to be solved by this invention is, in the mobile communication system of tdd mode, a kind of method that transmits and receives of MBMS business is provided, realizes the emission and the reception of MBMS business, not only avoided minizone MBMS traffic interference, but also can provide gain for UE receives the MBMS business.

The invention provides the method that multimedia broadcast multi-broadcasting business transmits and receives under a kind of TDD mode, between base station side and subscriber equipment, carry out transmitting and receiving of multimedia broadcast multi-broadcasting business, comprise the steps:

(1) base station controller sends the multimedia broadcast multi-broadcasting business MBMS data of same format, identical content simultaneously to each base station of being controlled, forms duplicate MBMS sign level data;

(2) each sub-district is carried out spectrum-spreading and scrambling respectively with the MBMS sign level data that obtains in the step (1), forms the baseband signal to be launched of each sub-district, and during emission, different training sequences is used in each sub-district;

(3) user equipment (UE) of receiving terminal detects the system information in the peripheral cell system broadcasts, obtain basic training sequences, spreading code and the scrambling code information of each sub-district, according to basic training sequences information each the sub-district training sequence that is received is carried out obtaining the pairing channel impulse response in each sub-district after the channel estimating, calculate the pairing sytem matrix in each sub-district respectively;

(4) the pairing sytem matrix in each sub-district that obtains in the step (3) is merged, obtain a hybrid system matrix, this hybrid system matrix is carried out united detection processing to the base band data that is received, obtain the professional initial data of MBMS.

Described base station controller is controlled a plurality of base stations, and wherein each base station is controlled some sub-districts again, and described each sub-district is to be in the synchro system.

Step (1) further can be divided into:

Base station controller sends the multimedia broadcast multi-broadcasting business MBMS data of same format, identical content simultaneously to each base station of being controlled;

All sub-districts that base station controller is controlled in each base station are carried out consistent business mapping processing respectively to these MBMS data, form the physical layer bit data flow;

Consistent data-modulated process is carried out to described physical layer bit data flow in all sub-districts that base station controller is controlled in each base station, forms all duplicate MBMS sign level data in each sub-district.

Step (2) further can be divided into:

The MBMS sign level data that each sub-district will obtain after business mapping and modulation is carried out spectrum-spreading and scrambling respectively, by the spreading code [C of each sub-district ₁, C ₂..., C _m] ^TDot product scrambler S _i=[s _I1, s _I2..., s _ISF] obtain the compound spreading code V of each sub-district correspondence _i, that is:

$V_i={[C_1,C_2,...,C_m]}^T\·S_i=\left[\begin{array}{cccc}{c}_{11}{s}_{i1}& c_{12}{s}_{i2}& L& c_{1\mathrm{SF}}{s}_{\mathrm{iSF}}\\ c_{21}{s}_{i1}& c_{22}{s}_{i2}& L& c_{2\mathrm{SF}}{s}_{\mathrm{iSF}}\\ M& M& O& M\\ c_{m1}{s}_{i1}& c_{m2}{s}_{i2}& L& c_{\mathrm{mSF}}{s}_{\mathrm{iSF}}\end{array}\right]$

Wherein, C _i=[c _I1, c _I2..., c _ISF], i=1 ..., m, SF are spreading factor;

Utilize the compound spreading code V of each sub-district _iTo MBMS sign level data data _iCarry out the spectrum-spreading and scrambling operation, that is: Tx _i=data _i.V _iI=1,2 ..., n forms the baseband signal to be launched of each sub-district;

During emission, each sub-district uses different training sequences to send this baseband signal Tx simultaneously at a time slot _i

Step (3) further can be divided into:

Described user equipment (UE) is according to the basic training sequences information M in each system information of subdistricts ₁, M ₂..., M _nTo the training sequence e that receives _MidCarry out channel estimating, calculate the channel impulse response of each sub-district according to channel estimation method

, i=1,2 ..., n;

Described user equipment (UE) utilizes the compound spreading code V of each sub-district _iWith the channel impulse response that estimates

Generate the sytem matrix of each sub-district

Step (4) further can be divided into:

With the pairing sytem matrix in each sub-district that obtains in the step (3) Merge, obtain a hybrid system matrix, promptly $\hat{A}=\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{\hat{A}}_i;$

With this hybrid system matrix The base band data that described subscriber equipment is received carries out united detection processing, the MBMS service symbol level business datum that obtains estimating

To described MBMS service symbol level data

Carry out demodulation, decoded operation, obtain the professional initial data of MBMS

In the step (4):

Described user equipment (UE) utilizes the joint-detection module that described hybrid system matrix is carried out the MBMS service symbol level data that united detection processing obtains estimating;

Described user equipment (UE) utilizes decoder module that the MBMS service symbol level data of described estimation are carried out demodulation operation;

Described user equipment (UE) utilizes decoding module that the MBMS service symbol level data of described estimation are carried out decoded operation.

The present invention provides a kind of method that effectively transmits and receives the MBMS business in the mobile communication system of tdd mode, this method can reduce traffic interference greatly, provide diversity gain for UE holds simultaneously, thereby improve MBMS service transmission performance in the tdd mode.

Description of drawings

Fig. 1 is the network configuration block diagram of the embodiment of the invention;

Fig. 2 is the base station end group tape handling flow chart of i sub-district in the embodiment of the invention;

Fig. 3 is the Base-Band Processing flow chart on the user terminal UE in the embodiment of the invention.

Embodiment

Below in conjunction with drawings and the specific embodiments technical solution of the present invention is described in further detail.

Because the TDD system distributed channel resource according to the time, each minizone is a synchro system, utilize the synchronizing characteristics of TDD system, make different sub-districts send identical MBMS business at synchronization, the UE end can receive the different copies from the same MBMS business of different districts in this time like this, these copies are carried out input and merge processing at the UE end, thereby obtain original MBMS business datum.Thereby can provide the inter-cell interference suppression ability, and improve the UE termination and receive gain, in the mobile communication system of tdd mode, implement the MBMS business effectively.

Professional physical layer emission of MBMS in the TDD mobile communication system that present embodiment relates to and method of reseptance, adopt many sub-district emission same MBMS business at transmitting terminal, receiving terminal adopts chip-level to merge the method for handling, thereby realizes the emission and the reception of multimedia broadcast multi-broadcasting business.For achieving the above object, the method that the MBMS business that provides in the present embodiment transmits and receives comprises the steps:

Step 1: under a base station controller, have a plurality of base stations, base station controller sends the MBMS business datum of same format, identical content simultaneously to each base station, and all sub-districts of controlling in each base station carry out the business mapping of same format to these MBMS data, and the data-modulated of carrying out model identical.Like this, each sub-district is duplicate through the MBMS data after data-modulated, just allows the duplicate MBMS data of the symbol level of these sub-districts after synchronization sends data-modulated:

Step 2: the MBMS sign level data that each sub-district will obtain in step 1 is carried out spectrum-spreading and scrambling respectively, forms each sub-district baseband signal to be launched, and finally these sub-districts send this MBMS business datum simultaneously at a time slot.

Step 3: the user equipment (UE) of receiving terminal (User Equipment) detects the system information in the peripheral cell system broadcasts, therefrom obtains basic training sequences, spreading code and the scrambling code information of a plurality of sub-districts; At first,, each the Zone training sequence that is received is carried out channel estimating, obtain the pairing channel impulse response in each sub-district according to the MBMS basic training sequences information that UE receives; Then, spreading code, scrambling code information and the channel impulse response according to each sub-district calculates the pairing sytem matrix in each sub-district respectively.Wherein, described system information sends to UE by system broadcasts, comprised basic training sequences, spreading code, the scrambler that adopt each sub-district in the system information, and used training sequence is the training sequence through channel that sends simultaneously with the MBMS business datum when carrying out channel estimating.

Step 4: the sytem matrix of each sub-district of obtaining in the step 3 is merged, obtain a hybrid system matrix, bring this this hybrid system matrix into UE joint-detection module and detect MBMS service symbol data, send into demodulation, decoding module then, finally obtain the professional initial data of MBMS.

Application example:

Be that example is carried out concrete description with the MBMS business in the TD-SCDMA communication system below:

Fig. 1 is the transmitting terminal of multimedia broadcast multi-broadcasting business MBMS in the present embodiment and the system flow block diagram of receiving terminal.In the TD-SCDMA system, base station controller control a plurality of base stations (base station 1 ..., base station m), a plurality of sub-districts can be controlled again in a base station.In the present embodiment, base station controller transmits identical MBMS business data flow to each sub-district, and it is just the same in the business mapping and the modulation system of same time slot to control each sub-district, spectrum-spreading and scrambling is carried out to this MBMS business datum respectively in each sub-district then, different scrambling codes is used in each sub-district, use different basic training sequences simultaneously, then each sub-district sends the MBMS business datum simultaneously; At user terminal UE, by detecting all system information of subdistricts, then according to the chip-level merge algorithm of present embodiment to data detect, demodulation, decoding, finally obtain original MBMS business datum.

Fig. 2 is i sub-district transmitting terminal process chart in the present embodiment.The transmitting terminal of present embodiment utilizes the characteristics of TD-SCDMA system for synchro system, makes a plurality of sub-districts launch identical MBMS business datum d at one time _MBMS

In step 201, the base station end group band of each sub-district carries out the business mapping respectively to these data to be handled, and forms the physical layer bit data flow.

In step 202, bit data flow is carried out data-modulated, form sign level data data _i, the sign level data of each sub-district is all the same, that is:

data＝data ₁＝data ₂＝...＝data _n

Wherein, on behalf of a target terminal user UE, n can receive the number of the sub-district of certain strength signal, data _nThe sign level data of then representing certain strength signal that described UE is received from n sub-district.

In step 203, m code channel spreading code is in the time slot in i sub-district: [C ₁, C ₂..., C _m] ^T, C wherein _i=[c _I1, c _I2..., c _ISF], i=1 ..., m, SF is a spreading factor, the scrambler of establishing i sub-district is S _i=[s _I1, s _I2..., s _ISF], the scrambler of spreading code and cell i can be formed the compound spreading code V of i sub-district like this _i, as follows:

$V_i={[C_1,C_2,...,C_m]}^T\·S_i=\left[\begin{array}{cccc}{c}_{11}{s}_{i1}& c_{12}{s}_{i2}& L& c_{1\mathrm{SF}}{s}_{\mathrm{iSF}}\\ c_{21}{s}_{i1}& c_{22}{s}_{i2}& L& c_{2\mathrm{SF}}{s}_{\mathrm{iSF}}\\ M& M& O& M\\ c_{m1}{s}_{i1}& c_{m2}{s}_{i2}& L& c_{\mathrm{mSF}}{s}_{\mathrm{iSF}}\end{array}\right]$

In view of the above, utilize the compound spreading code V of this sub-district _iTo sign level data data _iCarry out the spectrum-spreading and scrambling operation, that is:

Tx _i＝data _i·V _i i＝1，2，...，n

Thus, can obtain the baseband signal Tx to be launched of i sub-district _i, other each sub-district also adopts above-mentioned steps 201-203 to obtain the baseband signal to be launched of each sub-district, and each sub-district is at synchronization transmitting baseband signal.During emission, different basic training sequences: M is used in each sub-district ₁, M ₂..., M _n

Fig. 3 is the Base-Band Processing flow chart of receiving terminal in the present embodiment.At receiving terminal, the received signal of user terminal UE can be expressed as:

$R=\underset{j=1}{\overset{n}{\mathrm{\Σ}}}{\mathrm{Tx}}_j\·H_j=\mathrm{data}\·\underset{j=1}{\overset{n}{\mathrm{\Σ}}}(V_j*H_j)=\mathrm{data}\·A$

Wherein, $A=\underset{j=1}{\overset{n}{\mathrm{\Σ}}}(V_j*H_j)$ Be the hybrid system matrix that receiving terminal shows, (*) expression convolution operation.

In step 301, UE is at first according to the training sequence e of each system information of subdistricts to receiving _MidCarry out channel estimating, the basic training sequences of establishing i sub-district is M _i, can obtain the channel impulse response of each sub-district according to channel estimation method:

That is:

${\hat{H}}_i=\mathrm{IFFT}\left(\frac{\mathrm{FFT}\left(e_{\mathrm{mid}}\right)}{\mathrm{FFT}\left(M_i\right)}\right)$

System information is to launch in independent system broadcast channel, so be not included in the baseband signal that each sub-district is sent out in the step 203 among Fig. 2.In the baseband signal that the sub-district is sent out, inserted the training sequence that is used for channel estimating,, at first wherein training sequence has been carried out channel estimating so UE receives these baseband signals.

In step 302, utilize the compound spreading code V of each sub-district ₁, V ₂..., V _nWith the channel impulse response that estimates Generate the sytem matrix of each sub-district, be designated as respectively:

That is:

${\hat{A}}_i={\hat{H}}_i*V_i,i=\mathrm{1,2},...,n$

Wherein (*) represents convolution operation.

In step 303, these sytem matrixes are merged, constitute a hybrid system matrix

That is: $\hat{A}=\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{\hat{A}}_i$

In step 304, the data division e that UE is received _DataWith the hybrid system matrix

Carry out united detection processing, the symbol level MBMS business datum that obtains estimating

Wherein ( ^H) operation of expression conjugate transpose.

In step 305, with what estimate

Row demodulation, decoded operation obtain the professional initial data of final MBMS:

In sum, one aspect of the present invention can be avoided the problem of co-channel interference between the MBMS broadcasting service under the tdd mode, in addition, can utilize chip-level to merge processing gain is provided; Because this mode can send MBMS business at a high speed in a time slot, so system availability is than higher.Adopt method of the present invention, can in the TD-SCMDA system, support the MBMS business efficiently.

Claims (7)

1. the method that multimedia broadcast multi-broadcasting business transmits and receives under the TDD mode is carried out transmitting and receiving of multimedia broadcast multi-broadcasting business between base station side and subscriber equipment, it is characterized in that, comprises the steps:

(1) base station controller sends the multimedia broadcast multi-broadcasting business MBMS data of same format, identical content simultaneously to each base station of being controlled, forms duplicate MBMS sign level data;

(2) each sub-district is carried out spectrum-spreading and scrambling respectively with the MBMS sign level data that obtains in the step (1), forms the baseband signal to be launched of each sub-district, and during emission, different training sequences is used in each sub-district;

(3) user equipment (UE) of receiving terminal detects the system information in the peripheral cell system broadcasts, obtain basic training sequences, spreading code and the scrambling code information of each sub-district, according to basic training sequences information each the sub-district training sequence that is received is carried out obtaining the pairing channel impulse response in each sub-district after the channel estimating, calculate the pairing sytem matrix in each sub-district respectively;

(4) the pairing sytem matrix in each sub-district that obtains in the step (3) is merged, obtain a hybrid system matrix, this hybrid system matrix is carried out joint-detection, separates to be in harmonious proportion to decipher and handle the base band data that is received, obtain the professional initial data of MBMS.

2. the method for claim 1 is characterized in that, described base station controller is controlled a plurality of base stations, and wherein each base station is controlled some sub-districts again, and described each sub-district is to be in the synchro system.

3. the method for claim 1 is characterized in that, step (1) further can be divided into:

Base station controller sends the multimedia broadcast multi-broadcasting business MBMS data of same format, identical content simultaneously to each base station of being controlled;

All sub-districts that base station controller is controlled in each base station are carried out consistent business mapping processing respectively to these MBMS data, form the physical layer bit data flow;

Consistent data-modulated process is carried out to described physical layer bit data flow in all sub-districts that base station controller is controlled in each base station, forms all duplicate MBMS sign level data in each sub-district.

4. the method for claim 1 is characterized in that, step (2) further can be divided into:

The MBMS sign level data that each sub-district will obtain after business mapping and modulation is carried out spectrum-spreading and scrambling respectively, by the spreading code [C of each sub-district ₁, C ₂..., C _m] ^TDot product scrambler S _i=[s _I1, s _I2..., s _ISF] obtain the compound spreading code V of each sub-district correspondence _i, that is:

Wherein, C _i=[c _I1, c _I2..., c _ISF], i=1 ..., m, SF are spreading factor;

Utilize the compound spreading code V of each sub-district _iTo MBMS sign level data data _iCarry out the spectrum-spreading and scrambling operation, that is: Tx _i=data _iV _iI=1,2 ..., n forms the baseband signal to be launched of each sub-district; During emission, each sub-district uses different training sequences to send this baseband signal Tx simultaneously at a time slot _i

5. the method for claim 1 is characterized in that, step (3) further can be divided into:

Described user equipment (UE) is according to the basic training sequences information M in each system information of subdistricts ₁, M ₂..., M _nTo the training sequence e that receives _MidCarry out channel estimating, calculate the channel impulse response of each sub-district according to channel estimation method

I=1,2 ..., n;

Described user equipment (UE) utilizes the compound spreading code Vi of each sub-district and the channel impulse response that estimates

Generate the sytem matrix of each sub-district

6. as claim 1 or 5 described methods, it is characterized in that step (4) further can be divided into:

With the pairing sytem matrix in each sub-district that obtains in the step (3)

Merge, obtain a hybrid system matrix, promptly

With this hybrid system matrix

The base band data that described subscriber equipment is received carries out united detection processing, the MBMS service symbol level business datum that obtains estimating

To described MBMS service symbol level data

Carry out demodulation, decoded operation, obtain the professional initial data of MBMS

7. the method for claim 1 is characterized in that, in the step (4):

Described user equipment (UE) utilizes the joint-detection module that described hybrid system matrix is carried out the MBMS service symbol level data that united detection processing obtains estimating;

Described user equipment (UE) utilizes decoder module that the MBMS service symbol level data of described estimation are carried out demodulation operation;

Described user equipment (UE) utilizes decoding module that the MBMS service symbol level data of described estimation are carried out decoded operation.

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