CN102196495A - Downlink data transmission method, system and equipment - Google Patents

Abstract

The invention discloses a downlink data transmission method, a downlink data transmission system and downlink data transmission equipment, which relate to the field of wireless communication and are used for improving data transmission reliability and saving air-interface resources. The method comprises that: a base station allocates physical resource blocks (PRB) to a terminal according to channel quality indicator (CQI) information reported by the terminal and the current volume of downlink data to be transmitted; the base station determines a first modulation and coding scheme (MCS) level, wherein the first MCS level is lower than a second MCS level which is an MCS level determined according to signal-to-interference and noise ratios (SINR) on each PRB allocated to the terminal; the base station searches for an MCS form and a transport block size (TBS) form to obtain a TBS corresponding to the first MCS level and the total number of the PRBs allocated to the terminal; and the base station transmits the downlink data of the TBSs to the terminal by utilizing the PRBs allocated to the terminal. By the method, the system and the equipment, the data transmission reliability can be effectively improved, the repeat probability of a hybrid automatic repeat request (HARQ) can be reduced, and the wasting of air-interface resources can be effectively reduced.

Description

Downlink data transmission method, system and equipment

Technical field

The present invention relates to wireless communication field, relate in particular to a kind of downlink data transmission method, system and equipment.

Background technology

In Long Term Evolution (LTE) system, physical radio resource piece (PRB) is basic resource allocation unit, is used for carrying out the resource allocation of Physical Downlink Shared Channel (PDSCH) and Physical Uplink Shared Channel (PUSCH).A PRB is defined as the N of time domain _Symb ^ULIndividual continuous OFDM (OFDM) symbol and the N of frequency domain _Sc ^RBIndividual continuous sub-carriers, as shown in Figure 1.Descending N in the LTE system _Symb ^ULAnd N _Sc ^RBValue provide by table 1.As shown in Table 1, under the conventional CP, conventional PRB comprises 84 Resource Units (the resource granularity unit that RE is promptly minimum), a conventional PRB comprises 168 RE to (PRB Pair).

Table 1

When determining descending transmission block size (TBS) according to the LTE agreement, suppose under the conventional CP, the control area takies under the pilot-frequency expense condition of 3 OFDM symbols (being CFI=3), 2 antenna ports, each conventional PRB is to comprising 120 RE that can be used for business data transmission.

According to LTE system descending resource mapping ruler, the PRB that is used for the PDSCH transmission is to being perforated, and is with transmission downlink physical broadcast channel (PBCH), primary synchronization channel (PSCH), auxiliary synchronization channel (SSCH), that the PRB that is perforated is right to being called punching PRB.In addition; for time-division Long Term Evolution (TD-LTE) system; because part RE is perforated to be used for the protection transmission of time slot (GP), uplink special time slot (UpPTS) and PSCH at interval, it is right that the OFDM symbolic number that descending special time slot (DwPTS) takies is less than conventional PRB.Particularly, there are four kinds of right use-cases of punching PRB, as shown in table 2.Wherein, the schematic diagram of four of TD-LTE system convention CP kinds of use-cases is referring to Fig. 2.

Table 2

The use-case numbering	The use-case content
		Case1	For frame structure 1 and frame structure 2,6 PRB in the middle of the bandwidth of subframe 0, part of O FDM symbol are perforated and are used for PBCH and SCH transmission
Case2	For all PRB of DwPTS in the frame structure 2, the part running time-frequency resource is perforated and is used for GP, UpPTS transmission

Case3	For frame structure 1 and frame structure 2,6 PRB in the middle of the bandwidth of subframe 5, part of O FDM symbol are perforated and are used for the SSCH transmission
		Case4	For 6 PRB in the middle of the bandwidth of frame structure 2, subframe 1 and subframe 6, an OFDM symbol is perforated and is used for the PSCH transmission

Definite scheme of descending TBS belongs to the equipment problem of implementation in the LTE system, and the LTE agreement is not done unified regulation.At present a kind of common scheme of fixing capable TBS really is as shown in Figure 3:

Step 1: PRB number and the position of determining to distribute to terminal (UE) by the downlink resource distribution module.In the process of resource allocation, at first estimate the PRB number of distributing, further determine to distribute number and the position of PRB then according to subband CQI according to UE current transfer of data demand and broad-band channel quality indication (CQI) (being the Signal to Interference plus Noise Ratio (SINR) of full bandwidth).

Step 2: descending AMC module is selected modulation coding mode (MCS) grade according to the locational time domain SINR of PRB that distributes for UE.What use during base station selected MCS grade is to have carried out the SINR on each PRB that revises according to the CQI that UE reports.

Step 3: obtain MCS sign (MCS index) by the MCS selector, according to the mapping relations of MCS index and transmission block size sign (TBS index), tabling look-up obtains TBS index.The mapping form of descending MCS index and TBS index is referring to table 3.

Step 4: by the PRB number N_PRB of TBS index and CU, according to (TBS index N_PRB) with the mapping relations of TBS, obtains the size of TBS by searching the TBS form.Wherein, the TBS form is referring to table 4.

Table 3

Table 4

Being described as follows of his-and-hers watches 4: TBS form one has 27 row, 110 row, a kind of TBS call number of each line display I _TBS(value from 0 to 26 is corresponding to 29 kinds of MCS grades in the table 3), the PRB number N of distribution is shown in each tabulation _PRB(for the system bandwidth of 20MHz, from 1 to 110).For for simplicity, table 4 has provided N _PRBFrom 1 to 10 situation.

LTE agreement 36.213 regulations: for the special subframe configuration 0 and 5 of conventional CP, and the special subframe configuration 0 and 4 of expansion CP, DwPTS can not transmit data.Under other situation, DwPTS can transmitting downlink data.

When DwPTS transmission downlink service data, the processing method of terminal (UE) side is as follows:

Step 1:UE reads the MCS signaling I of 5 bits from the DCI signaling _MCS

Step 2:UE by resource allocation indication obtain current operable PRB number N ' _PRB

Step 3:UE calculates the PRB number N that is used to search the TBS form _PRB:

Step 4:, pass through I according to the MCS form _MCSObtain I _TBS, then according to TBS form and (I _TBS, N _PRB) determine TBS to the mapping relations of TBS.

In realizing process of the present invention, the inventor finds to exist in the prior art following technical problem:

Under four kinds of use-case situations shown in the table 2, the RE number that can be used for business data transmission, causes the actual bit rate of business datum to improve, thereby has reduced the detection performance of UE to this business datum significantly reducing with respect to conventional PRB, wasted interface-free resources, made a concrete analysis of as follows:

Present LTE agreement regulation, base station (eNodeB) when determining the TBS of business datum all be according to conventional PRB to designing, consider the right influence of punching PRB.Be that example describes with Case1 in the table 2 below: the PRB that supposes a routine is that the available RE number that 120, one punching PRB centerings comprise is 62 to the available RE number that comprises, and so, is distributing two PRB to (N _PRB=2) under the condition, punch PRB pair with the right spectrum efficiency of conventional PRB and code check referring to table 5.As shown in Table 5: two PRB that distribute when the eNodeB scheduler to all be punching PRB to the time (above-mentioned situation in 1.4M bandwidth, subframe 0 time be bound to occur), under 17 kinds of MCS grades, actual bit rate is all greater than 0.93, even greater than 1, UE is to the detection decreased performance of business datum even make a mistake, make the reliability of business data transmission reduce greatly, the HARQ that is caused when making a mistake retransmits has wasted interface-free resources greatly.

Table 5

I TBS	TBS (N PRB＝2)	Q m	The right spectrum efficiency (2*120REs) of conventional PRB	The right code check (2*120REs) of conventional PRB	The right spectrum efficiency (2*62REs) of punching PRB	The right code check (2*62REs) of punching PRB
							0	32	2	0.2333	0.1167	0.4516	0.2258
1	56	2	0.3333	0.1667	0.6452	0.3226
							2	72	2	0.4000	0.2000	0.7742	0.3871
3	104	2	0.5333	0.2667	1.0323	0.5161

4	120	2	0.6000	0.3000	1.1613	0.5806
							5	144	2	0.7000	0.3500	1.3548	0.6774
6	176	2	0.8333	0.4167	1.6129	0.8065
							7	224	2	1.0333	0.5167	2.0000	1.0000
8	256	2	1.1667	0.5833	2.2581	1.1290
							9	296	2	1.3333	0.6667	2.5806	1.2903
10	328	4	1.4667	0.3667	2.8387	0.7097
							11	376	4	1.6667	0.4167	3.2258	0.8065
12	440	4	1.9333	0.4833	3.7419	0.9355
							13	488	4	2.1333	0.5333	4.1290	1.0323
14	552	4	2.4000	0.6000	4.6452	1.1613
							15	600	4	2.6000	0.6500	5.0323	1.2581
16	632	6	2.7333	0.4556	5.2903	0.8817
							17	696	6	3.0000	0.5000	5.8065	0.9677
18	776	6	3.3333	0.5556	6.4516	1.0753
							19	840	6	3.6000	0.6000	6.9677	1.1613
20	904	6	3.8667	0.6444	7.4839	1.2473
							21	1000	6	4.2667	0.7111	8.2581	1.3763
22	1064	6	4.5333	0.7556	8.7742	1.4624
							23	1128	6	4.8000	0.8000	9.2903	1.5484
24	1192	6	5.0667	0.8444	9.8065	1.6344
							25	1256	6	5.3333	0.8889	10.3226	1.7204
26	1480	6	6.2667	1.0444	12.1290	2.0215

Summary of the invention

The embodiment of the invention provides a kind of downlink data transmission method, system and equipment, is used to improve reliability of data transmission, saves interface-free resources.

A kind of downlink data transmission method, this method comprises:

The base station is terminal distribution Physical Resource Block PRB according to the channel quality indicator (CQI) information and the current downlink data amount waiting for transmission of terminal to report;

The first modulation coding mode MCS grade is determined in the base station, and a MCS grade is less than the 2nd MCS grade, and the 2nd MCS grade is the MCS grade of determining according to for the Signal to Interference plus Noise Ratio SINR on each PRB of terminal distribution;

The base station obtains the pairing TBS of total number that a MCS grade reaches the PRB that is terminal distribution by searching MCS form and transmission block size TBS form;

The base station is utilized as the downlink data of the PRB of terminal distribution to the described TBS of terminal transmission.

A kind of wireless communication system, this system comprises:

The base station is used for channel quality indicator (CQI) information and current downlink data amount waiting for transmission according to terminal to report, is terminal distribution Physical Resource Block PRB; Determine the first modulation coding mode MCS grade, a MCS grade is less than the 2nd MCS grade, and the 2nd MCS grade is the MCS grade of determining according to for the Signal to Interference plus Noise Ratio SINR on each PRB of terminal distribution; By searching MCS form and transmission block size TBS form, obtain the pairing TBS of total number that a MCS grade reaches the PRB that is terminal distribution; Be utilized as the downlink data of the PRB of terminal distribution to the described TBS of terminal transmission; And will be included as total number of PRB of terminal distribution and the signaling of a MCS grade sends to terminal;

Terminal is used for a total number and a MCS grade according to described PRB, need to determine the TBS of reception, and according to the TBS downlink data receiving of determining.

A kind of base station, this base station comprises:

Resource allocation unit is used for channel quality indicator (CQI) information and current downlink data amount waiting for transmission according to terminal to report, is terminal distribution Physical Resource Block PRB;

MCS grade determining unit is used for determining a MCS grade, and a MCS grade is less than the 2nd MCS grade, and the 2nd MCS grade is the MCS grade of determining according to for the SINR on each PRB of terminal distribution;

The TBS determining unit is used for obtaining the pairing TBS of total number that a MCS grade reaches the PRB that is terminal distribution by searching MCS form and transmission block size TBS form;

Data transmission unit is used to be utilized as the downlink data of the PRB of terminal distribution to the described TBS of terminal transmission.

A kind of terminal, this terminal comprises:

The signaling receiving element is used to receive the total number of the Physical Resource Block PRB that is included as this terminal distribution that sends the base station and the signaling of MCS grade;

The TBS determining unit is used for total number and MCS grade according to described PRB, need to determine the TBS of reception,

The data decoding unit is used for receiving the downlink data that the base station sends according to the TBS that determines.

Among the present invention, after the base station is terminal distribution PRB according to the CQI information of terminal to report and current downlink data amount waiting for transmission, determine that beguine is according to the little MCS grade of determining for the SINR on each PRB of terminal distribution of the 2nd MCS grade, then by searching MCS form and transmission block size TBS form, obtain the pairing TBS of total number that a MCS grade reaches the PRB that is terminal distribution, and be utilized as the downlink data of the PRB of terminal distribution to this TBS of terminal transmission.As seen, among the present invention since a MCS grade less than the 2nd MCS grade, the TBS that obtains according to a MCS grade is also just less than the TBS that obtains according to the 2nd MCS grade, the actual spectrum efficiency that reaches also just reduces during transmitting downlink data so, the also corresponding reduction of adopting of code check, and then improved reliability of data transmission, and reduced the probability that HARQ retransmits, reduced waste effectively to interface-free resources.

Description of drawings

Fig. 1 is the schematic diagram of Physical Resource Block in the prior art;

Fig. 2 is the right schematic diagram of PRB that punches under the TD-LTE system convention CP in the prior art;

Fig. 3 is a LTE system descending TBS constant current journey really schematic diagram in the prior art;

The method flow schematic diagram that Fig. 4 provides for the embodiment of the invention;

Fig. 5 is the realization flow schematic diagram of the embodiment of the invention;

The system configuration schematic diagram that Fig. 6 provides for the embodiment of the invention;

The architecture of base station schematic diagram that Fig. 7 provides for the embodiment of the invention;

The terminal structure schematic diagram that Fig. 8 provides for the embodiment of the invention.

Embodiment

The embodiment of the invention provides a kind of downlink data transmission method, in this method, the code check that uses when reducing downlink data transmission by the MCS grade of adjusting the transfer of data employing is to improve data transmission credibility, reduce the HARQ retransmission probability, avoid waste effectively interface-free resources.

Referring to Fig. 4, the downlink data transmission method that the embodiment of the invention provides specifically may further comprise the steps:

Step 40: the base station is terminal distribution Physical Resource Block (PRB) according to channel quality indication (CQI) information and the current downlink data amount waiting for transmission of terminal to report;

Step 41: a MCS grade is determined in the base station, and a MCS grade is less than the 2nd MCS grade, and the 2nd MCS grade is the MCS grade of determining according to for the SINR on each PRB of terminal distribution;

Step 42: the base station obtains the pairing TBS of total number that a MCS grade reaches the PRB that is terminal distribution by searching modulation coding mode MCS form and transmission block size (TBS) form;

Step 43: the base station is utilized as the downlink data of PRB definite TBS in terminal transmission step 42 of terminal distribution.

In the step 41, the base station determines that a MCS grade can adopt following dual mode:

Mode one:

At first, the highest spectral efficiency that the current wireless channel can be supported is determined according to the CQI information that UE reports in the base station;

Then, the highest spectral efficiency that the base station can be supported according to wireless channel is determined the actual spectrum efficiency of using of current down physical channel (for example PDSCH), and this spectrum efficiency is less than described highest spectral efficiency.The highest spectral efficiency coupling that feasible real frequency spectrum efficient that is reached by this spectrum efficiency of configuration and wireless channel are supported;

At last, the base station obtains the pairing MCS grade of spectrum efficiency of the actual use of current down physical channel by searching the MCS form, and this MCS grade is defined as a MCS grade.

Mode two:

At first, the base station is according to be that time domain SINR on each PRB of terminal distribution selects the MCS grade, and that use when selecting the MCS grade is the SINR on each PRB that CQI that the base station reports according to UE has carried out correction;

Then, a MCS grade less than selected MCS grade is determined in the base station, and this MCS grade is defined as a MCS grade.

Certainly, definite mode of a MCS grade is not limited to above-mentioned dual mode, any determine less than the 2nd MCS grade and more than or equal to the mode of a MCS grade of MCS grade 0 all in protection scope of the present invention.

The spectrum efficiency of the actual use of current down physical channel is determined in the base station in the aforesaid way one, can be in the following way:

The spectrum efficiency of the actual use of down physical channel: η is determined in the base station according to following formula _Used=(1-λ ₂+ λ ₁λ ₂) η _{CQI_init}, wherein, η _{CQI_init}Be the highest spectral efficiency that the current wireless channel can be supported, λ ₁The expression base station be among the PRB that distributes of UE punching PRB to the number of the Resource Unit (RE) that comprises and conventional PRB ratio, λ to the number of the RE that comprises ₂The expression base station is the ratio of total number that PRB pair of punching and PRB are right among the PRB that distributes of UE.

Adopt aforesaid way can guarantee real spectrum efficiency (η _Real) highest spectral efficiency (η that can support with the current wireless channel _{CQI_init}) coupling.Certainly, the base station determines that the realization of the spectrum efficiency that current down physical channel can reach is not limited to aforesaid way, can also be to adopt mode the such as directly spectrum efficiency of the actual employing of current down physical channel is turned down, adjusted spectrum efficiency need be greater than 0.

After the step 41, the base station can send to terminal with being included as the total number of PRB of terminal distribution and the signaling of a MCS grade; Terminal need to determine the TBS of reception according to a total number and the MCS grade of the PRB that receives, and deciphers according to the downlink data that the TBS that determines sends the base station that receives, and then correct downlink data receiving.

Above-mentioned terminal need to determine the TBS of reception according to a total number and the MCS grade of the PRB that receives, and it is implemented as follows:

Terminal receives the current PRB number that uses and is N from downlink signaling _PRB

Terminal obtains a MCS grade and a N by searching the TBS table _PRBPairing TBS is defined as the TBS that needs receive with this TBS.

The present invention will be described below in conjunction with specific embodiment:

In the present embodiment, obtain owing to TBS searches the TBS form by MCS grade and PRB number, so eNodeB adjusts the MCS grade according to actual conditions among the present invention when sending, the UE side does not need to do individual processing.Specifically describe as follows: eNodeB is at the PRB number (N that keeps resource allocation _{PE, PRB} ^Init) under the constant condition, PRB is to all being under the right condition of conventional PRB among the PRB that joins that keeps the score, data volume waiting for transmission is TBS _Init, will exist the punching PRB to the time data volume TBS waiting for transmission _InitBe adjusted into TBS ', make and to have distributed punching PRB to only to distribute conventional PRB right, the spectrum efficiency under two kinds of conditions remains unchanged; The UE side need not unnecessary operation.Be the present invention do not need the LTE agreement at the punching PRB to doing independent regulation.

In the following description, suppose TBS _InitBe the descending data quantity transmitted that needs, N _{PE, PRB} ^NormalAnd N _{RE, PRB} ^PuncRepresent respectively a conventional PRB to the punching RE number of PRB, λ to comprising ₁Represent that a punching PRB is to the RE number that comprises and the conventional PRB ratio to the RE number that comprises, promptly

Suppose N _{PRB, all_normal}All PRB that are illustrated in distribution to all be conventional PRB under the condition, the number of the CQI that reports according to UE of the eNodeB scheduler PRB that should distribute, N _{PRB, used}The number of the PRB of expression eNodeB scheduler actual allocated (wherein, comprises N _{PRB, punc}Individual punching PRB to and N _{PRB, used}-N _{PRB, punc}Individual conventional PRB to), the note λ ₂PRB pair of expression punching with total PRB of actual allocated ratio to number, promptly ${\mathrm{\λ}}_2=\frac{N_{\mathrm{PRB},\mathrm{punc}}}{N_{\mathrm{PRB},\mathrm{used}}}.$

Concrete steps are referring to Fig. 5:

Beginning (Begin):

The CQI that step 50:eNodeB reports according to UE determines that the highest spectral efficiency that the current wireless channel can be supported is η _{CQI_init}(being target spectrum efficient);

Step 51:eNodeB is according to η _{CQI_init}With data volume TBS waiting for transmission _InitThe number of definite PRB that need distribute is N _{PRB, all_normal}(PRB that is comprised among the PRB that supposes to distribute to all be conventional PRB to);

Step 52:eNodeB keeps the number (N of the PRB of distribution _{PRB, all_normal}) constant, consider to exist the right influence of punching PRB, according to η _Used=(1-λ ₂+ λ ₁λ ₂) η _{CQI_init}Determine the spectrum efficiency (η of the actual use of PDSCH _Used), make by configuration η _UsedAnd the PDSCH real frequency spectrum efficient (η of feasible this moment _Real) and target spectrum efficient (η _{CQI_init}) coupling.Concrete derivation is as follows:

The PRB that note eNodeB actual needs distributes is N to number _{PRB, used}(number that guarantees PRB is constant, promptly satisfies N _{PRB, used}=N _{PRB, all_normal}), wherein comprise N _{PRB, punc}Individual punching PRB to and N _{PRB, all_normal}-N _{PRB, punc}Individual conventional PRB is right, and the number that PRB pair of note punching and total PRB of actual allocated are right has following ratio relation:

${\mathrm{\λ}}_2=\frac{N_{\mathrm{PRB},\mathrm{punc}}}{N_{\mathrm{PRB},\mathrm{all}\_\mathrm{normal}}}.$

In order to pass through configuration η _UsedGuarantee the real frequency spectrum efficient (η of PDSCH _Real) and target spectrum efficient (η _{CQI_init}) coupling, promptly satisfy following relational expression:

${\mathrm{\η}}_{\mathrm{COI}\_\mathrm{init}}=\frac{{\mathrm{TBS}}_{\mathrm{init}}}{N_{\mathrm{RE},\mathrm{PRB}}^{\mathrm{Normal}}\×N_{\mathrm{PRB},\mathrm{all}\_\mathrm{normal}}}\≈\frac{{\mathrm{TBS}}^{\′}}{N_{\mathrm{RE},\mathrm{PRB}}^{\mathrm{Normal}}\×(N_{\mathrm{PRB},\mathrm{all}\_\mathrm{normal}}-N_{\mathrm{PRB},\mathrm{punc}})+N_{\mathrm{RE},\mathrm{PRB}}^{\mathrm{Punc}}\×N_{\mathrm{PRB},\mathrm{punc}}}={\mathrm{\η}}_{\mathrm{Real}}---\left(1\right)$

By following formula as can be known:

$\frac{{\mathrm{TBS}}^{\′}}{{\mathrm{TBS}}_{\mathrm{init}}}\≈\frac{N_{\mathrm{RE},\mathrm{PRB}}^{\mathrm{Normal}}\×(N_{\mathrm{PRB},\mathrm{all}\_\mathrm{normal}}-N_{\mathrm{PRB},\mathrm{punc}})+N_{\mathrm{RE},\mathrm{PRB}}^{\mathrm{Punc}}\×N_{\mathrm{PRB},\mathrm{punc}}}{N_{\mathrm{RE},\mathrm{PRB}}^{\mathrm{Normal}}\×N_{\mathrm{PRB},\mathrm{all}\_\mathrm{normal}}}$

$=\frac{(N_{\mathrm{PRB},\mathrm{all}\_\mathrm{normal}}-N_{\mathrm{PRB},\mathrm{punc}})+{\mathrm{\λ}}_1\·N_{\mathrm{PRB},\mathrm{punc}}}{N_{\mathrm{PRB},\mathrm{all}\_\mathrm{normal}}}=1-{\mathrm{\λ}}_2+{\mathrm{\λ}}_1\·{\mathrm{\λ}}_2---\left(2\right)$

N according to actual needs data quantity transmitted TBS ' and distribution _{PRB, all_normal}Individual PRB determines the spectrum efficiency η of the actual use of current PDSCH _Used, be shown below:

${\mathrm{\η}}_{\mathrm{Used}}=\frac{{\mathrm{TBS}}^{\′}}{N_{\mathrm{RE},\mathrm{PRB}}^{\mathrm{Normal}}\×N_{\mathrm{PRB},\mathrm{all}\_\mathrm{normal}}}=\frac{{\mathrm{TBS}}^{\′}}{{\mathrm{TBS}}_{\mathrm{init}}}\·\frac{{\mathrm{TBS}}_{\mathrm{init}}}{N_{\mathrm{RE},\mathrm{PRB}}^{\mathrm{Normal}}\×N_{\mathrm{PRB},\mathrm{all}\_\mathrm{normal}}}=(1-{\mathrm{\λ}}_2+{\mathrm{\λ}}_1\·{\mathrm{\λ}}_2)\·{\mathrm{\η}}_{\mathrm{CQI}\_\mathrm{init}}---\left(3\right)$

Step 53:eNodeB is by η _UsedSearch the MCS grade (I that the MCS form obtains this moment _{MCS, Used}) and corresponding TBS grade I _{TBS, Used}

Step 54:eNodeB is according to PRB number (N _{PRB, all_normal}) and TBS grade (I _{TBS, Used}) search the data volume TBS ' that the TBS form is determined the PDSCH actual transmissions;

Step 55:eNodeB passes through the DCI signaling with N _{PRB, all_normal}And I _{MCS, Used}Send to UE;

Step 56:UE is according to the N by indicating in the DCI signaling _{PRB, all_normal}And I _{MCS, Used}Determine the data volume TBS ' of reception.

Finish (End).

Referring to Fig. 6, the embodiment of the invention also provides a kind of wireless communication system, and this system comprises:

Base station 60 is used for channel quality indicator (CQI) information and current downlink data amount waiting for transmission according to terminal to report, is terminal distribution Physical Resource Block PRB; Determine a MCS grade, a MCS grade is less than the 2nd MCS grade, and the 2nd MCS grade is the MCS grade of determining according to for the SINR on each PRB of terminal distribution; By searching modulation coding mode MCS form and transmission block size TBS form, obtain the pairing TBS of total number that a MCS grade reaches the PRB that is terminal distribution; Be utilized as the downlink data of the PRB of terminal distribution to the described TBS of terminal transmission;

Terminal 61 is used to receive described downlink data.

Described base station 60 is used for:

Determine the highest spectral efficiency (being target spectrum efficient) that the current wireless channel can be supported according to described CQI information;

Determine the spectrum efficiency of the actual use of down physical channel according to described highest spectral efficiency, this spectrum efficiency is less than described highest spectral efficiency;

By searching the MCS form, obtain the MCS grade of the spectrum efficiency correspondence of the actual use of described down physical channel, and this MCS grade is defined as a MCS grade.

Described base station 60 is used for:

Determine the spectrum efficiency of the actual use of down physical channel: η according to following formula _Used=(1-λ ₂+ λ ₁λ ₂) η _{CQI_init}, wherein, η _{CQI_init}Be the highest spectral efficiency (being target spectrum efficient) that described current wireless channel can be supported, λ ₁The expression base station be among the PRB that distributes of UE punching PRB to the number of the Resource Unit RE that comprises and conventional PRB ratio, λ to the number of the RE that comprises ₂The expression base station is the ratio of total number that PRB pair of punching and PRB are right among the PRB that distributes of UE.

Described base station 60 also is used for:

Send to terminal with being included as the total number of PRB of terminal distribution and the signaling of a MCS grade;

Described terminal 61 also is used for:

According to a total number and the MCS grade of the PRB that receives, need to determine the TBS of reception, and according to the TBS downlink data receiving of determining.

Described terminal 61 is used for:

From downlink signaling, receive the total number of the current PRB that uses and be N _PRB

By searching MCS form and TBS form, obtain a MCS grade and a N _PRBPairing TBS is defined as the TBS that needs receive with this TBS.

Referring to Fig. 7, the embodiment of the invention also provides a kind of base station, and this base station comprises:

Resource allocation unit 70 is used for channel quality indicator (CQI) information and current downlink data amount waiting for transmission according to terminal to report, is terminal distribution Physical Resource Block PRB;

MCS grade determining unit 71 is used for determining a MCS grade, and a MCS grade is less than the 2nd MCS grade, and the 2nd MCS grade is the MCS grade of determining according to for the SINR on each PRB of terminal distribution;

TBS determining unit 72 is used for obtaining the pairing TBS of total number that a MCS grade reaches the PRB that is terminal distribution by searching modulation coding mode MCS form and transmission block size TBS form;

Data transmission unit 73 is used to be utilized as the downlink data of the PRB of terminal distribution to the described TBS of terminal transmission.

Described MCS grade determining unit 71 comprises:

The spectrum efficiency determining unit is used for determining the highest spectral efficiency (being target spectrum efficient) that the current wireless channel can be supported according to described CQI information;

The spectrum efficiency adjustment unit is used for determining according to described highest spectral efficiency the spectrum efficiency of the actual use of down physical channel, and this spectrum efficiency is less than described highest spectral efficiency;

MCS table lookup unit is used for obtaining the MCS grade of the spectrum efficiency correspondence of the actual use of described down physical channel by searching the MCS form, and this MCS grade is defined as a MCS grade.

Described spectrum efficiency adjustment unit is used for:

Determine the spectrum efficiency of the actual use of down physical channel: η according to following formula _Used=(1-λ ₂+ λ ₁λ ₂) η _{CQI_init}, wherein, η _{CQI_init}Be the highest spectral efficiency (being target spectrum efficient) that described current wireless channel can be supported, λ ₁The expression base station be among the PRB that distributes of UE punching PRB to the number of the Resource Unit RE that comprises and conventional PRB ratio, λ to the number of the RE that comprises ₂The expression base station is the ratio of total number that PRB pair of punching and PRB are right among the PRB that distributes of UE.

This base station also comprises:

Signaling transmission unit 74 is used for sending to terminal with being included as the total number of PRB of terminal distribution and the signaling of a MCS grade, determines the TBS that needs receive with indicating terminal according to a total number and the MCS grade of this PRB.

Referring to Fig. 8, the embodiment of the invention also provides a kind of terminal, and this terminal comprises:

Signaling receiving element 80 is used to receive the total number of the Physical Resource Block PRB that is included as this terminal distribution that sends the base station and the signaling of MCS grade;

TBS determining unit 81 is used for total number and MCS grade according to described PRB, need to determine the TBS of reception;

Data Receiving unit 82 is used for receiving the downlink data that send the base station according to the TBS that determines.

Described TBS determining unit 81 is used for:

By searching MCS form and TBS form, obtain the pairing TBS of total number of described MCS grade and described PRB, this TBS needing to be defined as the TBS of reception.

To sum up, beneficial effect of the present invention comprises:

In the scheme that the embodiment of the invention provides, after the base station is terminal distribution PRB according to the CQI information of terminal to report and current downlink data amount waiting for transmission, determine that beguine is according to the little MCS grade of determining for the SINR on each PRB of terminal distribution of the 2nd MCS grade, then by searching transmission block size TBS table, obtain the pairing TBS of total number that a MCS grade reaches the PRB that is terminal distribution, and be utilized as the downlink data of the PRB of terminal distribution to this TBS of terminal transmission.As seen, among the present invention since a MCS grade of determining less than the 2nd MCS grade, the actual spectrum efficiency that reaches also just reduces during transmitting downlink data so, the also corresponding reduction of adopting of code check, and then improved reliability of data transmission, reduced the probability that HARQ retransmits, reduced waste effectively interface-free resources.

Obviously, those skilled in the art can carry out various changes and modification to the present invention and not break away from the spirit and scope of the present invention.Like this, if of the present invention these are revised and modification belongs within the scope of claim of the present invention and equivalent technologies thereof, then the present invention also is intended to comprise these changes and modification interior.

Claims (15)

1. a downlink data transmission method is characterized in that, this method comprises:

The base station is terminal distribution Physical Resource Block PRB according to the channel quality indicator (CQI) information and the current downlink data amount waiting for transmission of terminal to report;

The first modulation coding mode MCS grade is determined in the base station, and a MCS grade is less than the 2nd MCS grade, and the 2nd MCS grade is the MCS grade of determining according to for the Signal to Interference plus Noise Ratio SINR on each PRB of terminal distribution;

The base station obtains the pairing TBS of total number that a MCS grade reaches the PRB that is terminal distribution by searching MCS form and transmission block size TBS form;

The base station is utilized as the downlink data of the PRB of terminal distribution to the described TBS of terminal transmission.

2. the method for claim 1 is characterized in that, described base station determines that a MCS grade comprises:

The highest spectral efficiency that the current wireless channel can be supported is determined according to described CQI information in the base station;

The spectrum efficiency of the actual use of down physical channel is determined according to described highest spectral efficiency in the base station, and this spectrum efficiency is less than described highest spectral efficiency;

The base station obtains the MCS grade of the spectrum efficiency correspondence of the actual use of described down physical channel by searching the MCS form, and this MCS grade is defined as a MCS grade.

3. method as claimed in claim 2 is characterized in that, the spectrum efficiency η of the actual use of down physical channel is determined in described base station according to following formula _Used:

η _Used=(1-λ ₂+ λ ₁λ ₂) η _{CQI_init}, wherein, η _{CQI_init}Be the highest spectral efficiency that described current wireless channel can be supported, λ ₁The expression base station be among the PRB of terminal distribution punching PRB to the number of the Resource Unit RE that comprises and conventional PRB ratio, λ to the number of the RE that comprises ₂The expression base station is the ratio of the right total number of PRB pair of PRB centering punching and the PRB of terminal distribution.

4. as claim 1 or 2 or 3 described methods, it is characterized in that after a MCS grade was determined in the base station, this method further comprised:

The base station will send to terminal for total number of the PRB of terminal distribution and the information of a MCS grade;

Terminal need to determine the TBS of reception according to the total number of the PRB that receives and the information of a MCS grade, and according to the TBS downlink data receiving of determining.

5. method as claimed in claim 4 is characterized in that, described terminal need to determine the TBS that receives to comprise according to the total number of the PRB that receives and the information of a MCS grade:

By searching MCS form and TBS form, obtain total number and the pairing TBS of a MCS grade of described PRB, this TBS needing to be defined as the TBS of reception.

6. a wireless communication system is characterized in that, this system comprises:

The base station is used for channel quality indicator (CQI) information and current downlink data amount waiting for transmission according to terminal to report, is terminal distribution Physical Resource Block PRB; Determine the first modulation coding mode MCS grade, a MCS grade is less than the 2nd MCS grade, and the 2nd MCS grade is the MCS grade of determining according to for the Signal to Interference plus Noise Ratio SINR on each PRB of terminal distribution; By searching MCS form and transmission block size TBS form, obtain the pairing TBS of total number that a MCS grade reaches the PRB that is terminal distribution; Be utilized as the downlink data of the PRB of terminal distribution to the described TBS of terminal transmission; And will be included as total number of PRB of terminal distribution and the signaling of a MCS grade sends to terminal;

Terminal is used for a total number and a MCS grade according to described PRB, need to determine the TBS of reception, and according to the TBS downlink data receiving of determining.

7. system as claimed in claim 6 is characterized in that, described base station is used for:

Determine the highest spectral efficiency that the current wireless channel can be supported according to described CQI information;

Determine the spectrum efficiency of the actual use of down physical channel according to described highest spectral efficiency, this spectrum efficiency is less than described highest spectral efficiency;

By searching the MCS form, obtain the MCS grade of the spectrum efficiency correspondence of the actual use of described down physical channel, and this MCS grade is defined as a MCS grade.

8. system as claimed in claim 7 is characterized in that, described base station is used for:

Determine the spectrum efficiency η of the actual use of down physical channel according to following formula _Used: η _Used=(1-λ ₂+ λ ₁λ ₂) η _{CQI_init}, wherein, η _{COQ_init}Be the highest spectral efficiency that described current wireless channel can be supported, λ ₁The expression base station be among the PRB of terminal distribution punching PRB to the number of the Resource Unit RE that comprises and conventional PRB ratio, λ to the number of the RE that comprises ₂The expression base station is the ratio of the right total number of PRB pair of PRB centering punching and the PRB of terminal distribution.

9. as claim 6 or 7 or 8 described systems, it is characterized in that described terminal is used for:

By searching MCS form and TBS form, obtain the pairing TBS of total number of a MCS grade and described PRB, this TBS needing to be defined as the TBS of reception.

10. a base station is characterized in that, this base station comprises:

Resource allocation unit is used for channel quality indicator (CQI) information and current downlink data amount waiting for transmission according to terminal to report, is terminal distribution Physical Resource Block PRB;

MCS grade determining unit is used for determining the first modulation coding mode MCS grade, and a MCS grade is less than the 2nd MCS grade, and the 2nd MCS grade is the MCS grade of determining according to for the SINR on each PRB of terminal distribution;

The TBS determining unit is used for obtaining the pairing TBS of total number that a MCS grade reaches the PRB that is terminal distribution by searching MCS form and transmission block size TBS form;

Data transmission unit is used to be utilized as the downlink data of the PRB of terminal distribution to the described TBS of terminal transmission.

11. base station as claimed in claim 10 is characterized in that, described MCS grade determining unit comprises:

The spectrum efficiency determining unit is used for determining the highest spectral efficiency that the current wireless channel can be supported according to described CQI information;

The spectrum efficiency adjustment unit is used for determining according to described highest spectral efficiency the spectrum efficiency of the actual use of down physical channel, and this spectrum efficiency is less than described highest spectral efficiency;

MCS table lookup unit is used for obtaining the MCS grade of the spectrum efficiency correspondence of the actual use of described down physical channel by searching the MCS form, and this MCS grade is defined as a MCS grade.

12. base station as claimed in claim 11 is characterized in that, described spectrum efficiency adjustment unit is used for:

Determine the spectrum efficiency η of the actual use of down physical channel according to following formula _Used: η _Used=(1-λ ₂+ λ ₁λ ₂) η _{CQI_init}, wherein, η _{CQI_init}Be the highest spectral efficiency that described current wireless channel can be supported, λ ₁The expression base station be among the PRB of terminal distribution punching PRB to the number of the Resource Unit RE that comprises and conventional PRB ratio, λ to the number of the RE that comprises ₂The expression base station is the ratio of total number that PRB pair of punching and PRB are right among the PRB of terminal distribution.

13., it is characterized in that this base station comprises as claim 10 or 11 or 12 described base stations:

The signaling transmission unit is used for sending to terminal with being included as the total number of PRB of terminal distribution and the signaling of a MCS grade, determines the TBS that needs receive with indicating terminal according to a total number and the MCS grade of this PRB.

14. a terminal is characterized in that, this terminal comprises:

The signaling receiving element is used to receive the total number of the Physical Resource Block PRB that is included as this terminal distribution that sends the base station and the signaling of MCS grade;

The TBS determining unit is used for total number and MCS grade according to described PRB, need to determine the TBS of reception;

The data decoding unit is used for receiving the downlink data that the base station sends according to the TBS that determines.

15. terminal as claimed in claim 14 is characterized in that, described TBS determining unit is used for:

By searching MCS form and TBS form, obtain the pairing TBS of total number of described MCS grade and described PRB, this TBS needing to be defined as the TBS of reception.

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