CN105338024A - Data transmission method of CBTC service - Google Patents

Abstract

The invention discloses a data transmission method of a CBTC service. The method comprises the following steps that in a frame structure of a system, CBTC special subframes which are periodically distributed are configured, and the CBTC special subframes are used for preferentially or only transmitting data of the CBTC service; a base station transmits the data of the CBTC service on the CBTC special subframes according to scheduling to the CBTC service. By using the method, a transmission requirement including low time delay and a stable rate of the CBTC service can be satisfied.

Description

A kind of data transmission method of CBTC business

Technical field

The application relates to the communication technology, particularly the data transmission method of a kind of train automatic controlling system based on radio communication (CBTC) business.

Background technology

CBTC system is the control system of track traffic, and CBTC business data transmission requires low time delay, rate stabilization.Current CBTC system does not also carry out practical application at LTE wireless network, and LTE wireless system has that throughput is large, time delay is low, dispose feature flexibly, can meet the feature of CBTC low time delay, rate stabilization.

But LTE system dispatching algorithm is unspecial at present specifies Qos standard to CBTC business, also special disposal is not carried out to CBTC, due to the dispatching priority of CBTC cannot be ensured, CBTC business can be caused to there is congested can not process in time, finally cannot ensure the low time delay requirement of CBTC.Meanwhile, current LTE system dispatching algorithm is unspecial carries out optimizing scheduling for CBTC business, can not ensure stable throughput, and CBTC needs to ensure certain capacity and stable bandwidth, and both exist contradiction.

Summary of the invention

The application provides a kind of data transmission method of CBTC business, can ensure the requirement of CBTC business to low time delay and rate stabilization.

For achieving the above object, the application adopts following technical scheme:

A data transmission method for CBTC business, comprising:

The special subframe of CBTC of configuration cycle property distribution in the frame structure of system, for preferentially or only transmitting the data of CBTC business;

The data of described CBTC business, in the special subframe of described CBTC, according to the scheduling to described CBTC business, are transmitted in base station.

Preferably, the special subframe of described configuration CBTC comprises: configure the cycle of the special subframe of CBTC, length and sub-frame offset.

Preferably, described sub-frame offset is configured on downlink frame or synchronization frame.

Preferably, when base station is dispatched described CBTC business, described CBTC dispatching priority is higher than DTCH retransfer scheduling priority.

Preferably, when transmitting the data of described CBTC business, UE carries out separately the statistics of BLER to described CBTC business, and according to the CQI that this BLER safeguards described CBTC business, feeds back to described base station.

Preferably, when transmitting the data of described CBTC business, in the MCS exponent number calculated according to CQI and the MCS exponent number upper limit preset, get minimum value, as MCS exponent number during described CBTC business data transmission.

Preferably, in advance for described CBTC business first biography and retransmit set maximum delay respectively;

Base station is when dispatching described CBTC business, if the first biography/retransfer scheduling of described CBTC business is less than or equal to corresponding maximum delay, then, in other subframes except the special subframe of described CBTC, does not carry out the scheduling of described CBTC business; If the first biography/retransfer scheduling of described CBTC business is greater than corresponding maximum delay, the method comprises further: in other subframes except the special subframe of described CBTC, also carries out the scheduling of described CBTC business.

As seen from the above technical solution, in the application, the special subframe of CBTC of configuration cycle property distribution in the frame structure of TD-LTE, for preferentially or only transmitting the data of CBTC business; The data of CBTC business, in the special subframe of CBTC, according to the scheduling to CBTC business, are transmitted in base station.By the mode of the application, be the special subframe of CBTC business setting, may be used for prioritised transmission or only transmit CBTC business datum, thus the low time delay of CBTC business datum and the transmission requirement of rate stabilization can be realized.

Accompanying drawing explanation

Fig. 1 is the method flow schematic diagram of CBTC business data transmission in the application;

Fig. 2 is the configuration schematic diagram of the special subframe of CBTC in the application;

Fig. 3 is the dispatching priority schematic diagram of CBTC business in the application.

Embodiment

In order to make the object of the application, technological means and advantage clearly understand, below in conjunction with accompanying drawing, the application is described in further details.

Fig. 1 is the flow chart of CBTC business transmission in the application.As shown in Figure 1, the method comprises:

Step 101, the special subframe of CBTC of configuration cycle property distribution in the frame structure of system, for preferentially or only transmitting the data of CBTC business.

In order to ensure the stable bandwidth sum low time delay of CBTC business, specially for CBTC business marks fixing subframe for CBTC business in the application.When specifically carrying out special sub-frame configuration, can be realized by the cycle of the special subframe of configuration CBTC, length and sub-frame offset.Such as, the special sub-frame configuration shown in Fig. 2.As shown in Figure 2, the cycle being configured the special subframe of CBTC and the special subframe of non-CBTC by parameter Period is arranged, configure the original position of the special subframe of CBTC in configuration cycle Period by Cbtcoffset, configured the length of the special subframe of CBTC in each cycle by Cbtclength.Wherein, when carrying out the configuration of three parameters, ensure Cbtcoffset+Cbtclength<=CbtcPeriod, original position Cbtcoffset is configured on descending D frame or S frame simultaneously, can ensure that the special subframe of CBTC is from descending sub frame like this.

After above-mentioned configuration, the special subframe of CBTC is only for dispatching CBTC business, or the special subframe of this CBTC is used for priority scheduling CBTC business, during the special subframe of CBTC still available free after CBTC traffic scheduling completes, this CBTC special subframe scheduling general service data can be utilized.In cycle Period, all the other subframes except the special subframe of CBTC are the special subframe of non-CBTC, for dispatching non-CBTC business.The above-mentioned configuration parameter for the special subframe of CBTC can be configured to base station by high-rise as cell-level algorithm parameter.

Step 102, base station is dispatched CBTC data.

When to CBTC scheduling service data, in order to CBTC business and other general servicies are distinguished, special processing can be carried out on QOS, in the differentiation process that current QOS dispatches, be mainly reflected on dispatching priority, therefore in the application, preferably, the priority of CBTC business is carried out special disposal, the first biography of CBTC business and the dispatching priority of re-transmission is set to the dispatching priority just passing higher than DTCH and retransmit.Wherein, the transfer of data of general service belongs to first biography and the re-transmission of DTCH.Specifically can shown in dispatching priority as shown in Figure 3.In figure 3, from start to end, the dispatching priority of corresponding service reduces successively, as shown in Figure 3, the re-transmission of CBTC business and the first process passed are extracted separately from general service process, be placed between DCCH and DTCH retransfer scheduling, can ensure that the priority of the business of CBTC is higher than general service.

Step 103, the data of CBTC business, according to the scheduling to CBTC business, in the special subframe of CBTC, are transmitted in base station.

The special subframe of CBTC is carried out the transmission of CBTC business datum.When carrying out concrete transfer of data, in order to reduce the error rate of CBTC, ensure the reliability of CBTC, MCS exponent number upper limit when just passing CBTC and retransmit limits.Particularly, pre-set the MCS exponent number upper limit CBTC_MCX_MAX of CBTC transmission, when carrying out MCS and selecting, according to the MCS exponent number I that current CQI information calculating CBTC just passes/retransmits _{mCS just passes}/ I _{mCS retransmits}, between the MCS exponent number calculated and the default MCS exponent number upper limit, then get minimum value as the MCS exponent number selected.That is:

MCS _{cTBC just passes}=min{I _{mCS just passes}, CTBC_MCS_MAX}

MCS _{cTBC retransmits}=min{I _{mCS retransmits}, CTBC_MCS_MAX}

Wherein, when arranging MCS exponent number upper limit CBTC_MCX_MAX, can be in the demand of network planning phase according to CBTC traffic carrying capacity and service bandwidth, and the need integrate of the service bandwidth of general service determine CBTC_MCX_MAX.

In addition, I is calculated _{mCS just passes}and I _{mCS retransmits}time, can be adopt identical account form with general data.Or, more preferably, UE can calculate respective BLER respectively to CBTC business and common PS business, when determining CQI information, the adjustment of CQI is carried out respectively respectively according to the BLER of CBTC business and common PS business statistics, safeguard CBTC business and common PS business CQI information separately respectively, and feed back to base station.Like this, base station, when calculating the MCS exponent number of CBTC business, just can calculate I according to the CQI information of CBTC business _{mCS just passes}and I _{mCS retransmits}, thus improve the accuracy of MCS exponent number selection.

So far, the transmission method flow process of the CBTS business datum in the application terminates.

In the above-mentioned methods, in order to the low time delay and bandwidth that ensure CBTC business are stablized, go specially to be optimized for CBTC business from LTE dispatching algorithm aspect, special subframe be marked off specially to CBTC business from physical resource, the priority of adjustment CBTC business, ensures that CBTC business can be dispatched in time, thus ensures that CBTC business has stable bandwidth sum low time delay, the MCS upper limit simultaneously for CBTC traffic scheduling limits, and makes CBTC business have the lower error rate.

In addition, in the process above, CBTC business is transmitted always in the special subframe of CBTC, for ensureing the low time delay that CBTC business is transmitted further, where necessary, CBTC business can also seize the transfer of data that the special subframe of non-CBTC carries out CBTC business, particularly, can be handled as follows when dispatching CBTC business:

In advance for CBTC business first biography and retransmit set maximum delay respectively; Base station, when dispatching CBTC business, if the first biography/retransfer scheduling of CBTC business is less than or equal to corresponding maximum delay, then, in the special subframe of non-CBTC, is not carried out the scheduling of CBTC business, is carried out normal consistency in the special subframe of CBTC; If the first biography/retransfer scheduling of CBTC business is greater than corresponding maximum delay, then, in the special subframe of CBTC and the special subframe of non-CBTC, all carry out the scheduling of CBTC business.That is, when prolonging larger when deployed, CBTC business can seize the transmission that the special subframe of non-CBTC carries out CBTC business datum, thus can ensure the low time delay requirement of CBTC business.Here, maximum delay can be configured to base station by high level as cell-level parameter.

By above-mentioned process, CBTC service resources can be prevented limited, utilize subframe preemptive policy, enable CBTC utilize extra interface-free resources to dispatch.

The foregoing is only preferred embodiment of the present invention, not in order to limit the present invention, within the spirit and principles in the present invention all, any amendment made, equivalent replacement, improvement etc., all should be included within the scope of protection of the invention.

Claims (7)

1. a data transmission method for CBTC business, is characterized in that, comprising:

The special subframe of CBTC of configuration cycle property distribution in the frame structure of system, for preferentially or only transmitting the data of CBTC business;

The data of described CBTC business, in the special subframe of described CBTC, according to the scheduling to described CBTC business, are transmitted in base station.

2. method according to claim 1, is characterized in that, the special subframe of described configuration CBTC comprises: configure the cycle of the special subframe of CBTC, length and sub-frame offset.

3. method according to claim 2, is characterized in that, is configured on downlink frame or synchronization frame by described sub-frame offset.

4. method according to claim 1, is characterized in that, when base station is dispatched described CBTC business, described CBTC dispatching priority is higher than DTCH retransfer scheduling priority.

5. method according to claim 1, is characterized in that, when transmitting the data of described CBTC business, UE carries out separately the statistics of BLER to described CBTC business, and according to the CQI that this BLER safeguards described CBTC business, feeds back to described base station.

6. method according to claim 1 or 5, it is characterized in that, when transmitting the data of described CBTC business, in the MCS exponent number calculated according to CQI and the MCS exponent number upper limit preset, get minimum value, as MCS exponent number during described CBTC business data transmission.

7. method according to claim 1, is characterized in that, is that first biography and the re-transmission of described CBTC business sets maximum delay respectively in advance;

Base station is when dispatching described CBTC business, if the first biography/retransfer scheduling of described CBTC business is less than or equal to corresponding maximum delay, then, in other subframes except the special subframe of described CBTC, does not carry out the scheduling of described CBTC business; If the first biography/retransfer scheduling of described CBTC business is greater than corresponding maximum delay, the method comprises further: in other subframes except the special subframe of described CBTC, also carries out the scheduling of described CBTC business.