CN104936301A - A Downlink Frequency Selection Scheduling Method - Google Patents

Abstract

The invention discloses a downlink frequency selection scheduling method, comprising: A. base station calculating the wideband SINR _MCS of user equipment; B. base station converting subband differential channel quality indication CQI reported by user equipment into corresponding subband SINR difference ΔSINR _sub ; C, calculate the equivalent SINR of each subband of the user equipment as SINR _sub = SINR _MCS + ΔSINR _sub ; D, select according to the equivalent SINR of each subband of the user equipment Modulation and coding strategy MCS in frequency selective scheduling. The technical solution of the present application can improve the downlink throughput of the broadband communication system under various complicated network deployment situations.

Description

A Downlink Frequency Selection Scheduling Method

technical field

The present application relates to the technical field of wireless communication, and in particular to a downlink frequency selection scheduling method.

Background technique

The LTE system is a B3G (Beyond Third Generation) broadband communication system, which provides larger transmission bandwidth and higher transmission rate. Due to the increase of transmission bandwidth, the influence of multipath delay increases, and the transmission channel Embody frequency selective gain over the entire bandwidth. In order to make full use of the above features, the UE can periodically (or aperiodically) feed back a Channel Quality Indicator (CQI, Channel Quality Indicator), and the base station supports frequency selective scheduling based on the CQI reported by the UE to maximize system throughput. Due to the complex interference changes in the LTE network deployment environment, the accuracy of the CQI reported by the UE is affected, and the downlink frequency selection and scheduling performance of the base station is also affected, so the system throughput is also affected.

Contents of the invention

The present application provides a downlink frequency selective scheduling method, which can improve the downlink throughput of a broadband communication system under various complex network deployment conditions.

A downlink frequency selection scheduling method provided in an embodiment of the present application includes:

A. The base station calculates the broadband SINR _MCS of the user equipment;

B. The base station converts the sub-band differential channel quality indicator CQI reported by the user equipment into the signal-to-interference-noise ratio difference ΔSINR _sub of the corresponding sub-band;

C. Calculate the equivalent signal-to-interference-noise ratio of each subband of the user equipment as SINR _sub = SINR _MCS + ΔSINR _sub ;

D. Selecting a modulation and coding strategy MCS in frequency selective scheduling according to the equivalent signal-to-interference-noise ratio of each subband of the user equipment.

Preferably, step A includes:

A1. The base station side dynamically adjusts the broadband signal-to-interference-noise ratio SINR _MCS of the user equipment according to the first transmission ACK/NACK information of the user equipment;

A2, the base station counts the broadband CQI reported by the user equipment, and converts the broadband CQI statistical value into an equivalent SINR threshold SINR _CQI ;

A3. Determine whether the variation trends of the wideband SINR _MCS and the equivalent SINR threshold SINR _CQI are consistent, if consistent, proceed to step A4, otherwise proceed to step B;

A4. Adjust the wideband SINR _MCS according to the equivalent SINR threshold SINR _CQI .

Preferably, step A1 includes: the user equipment receives the physical downlink shared channel information transmitted for the first time, and if it feeds back an acknowledgment ACK to the information, then increases the current wideband SINR _MCS by an increasing step value Δ _up , that is, SINR _MCS = SINR _MCS +Δ _up ; if the negative response NACK is fed back to the PDSCH information, the current wideband SINR _MCS is lowered by a down step value Δ _down , that is, SINR _MCS =SINR _MCS -Δ _down , where Δ _up /Δ _down =bler /(1-bler).

Preferably, the value range of the down step value Δ _down is (0,1]dB.

Preferably, step A4 is: adjust the wideband signal-to-interference-noise ratio SINR _MCS according to the following formula:

SINR _MCS =SINR _MCS ×alfa+SINR _CQI ×(1-alfa), where alfa is a filter factor.

From the above technical solutions, it can be seen that the subband CQI reflects the relative change of the subband channel gain in the frequency domain, and the equivalent SINR of the subband reflects the interference level of the corresponding subband more accurately than the wideband SINR. It adapts to the characteristic that the transmission channel in the broadband communication system reflects the frequency selective gain in the entire bandwidth, and is suitable for improving the downlink throughput of the broadband communication system in various complex network deployment situations.

Description of drawings

FIG. 1 is a schematic flow diagram of a downlink frequency selection scheduling method provided by the present application;

Fig. 2 is a schematic diagram of the implementation flow of the downlink frequency selection scheduling method provided by a preferred embodiment of the present application.

Detailed ways

The downlink frequency selection scheduling method provided by this application considers that changes in the interference level of the LTE system affect the accuracy of the CQI reported by the UE, and the obtained sub-band differential CQI reflects the relative change of the sub-band channel gain in the frequency domain. Therefore, a statistical method is designed to track the UE channel The wideband CQI changes to avoid the impact of external interference changes on the accuracy of the CQI reported by the UE. At the same time, combined with the subband differential CQI reported by the UE for frequency selection scheduling, it is suitable for improving downlink throughput in various complex network deployment situations.

The flow of the downlink frequency selection scheduling method provided by this application is shown in Figure 1, including the following steps:

Step 101: the base station counts the broadband SINR _MCS of the user equipment;

Step 102: The base station converts the sub-band differential CQI reported by the user equipment into the SINR difference ΔSINR _sub of the corresponding sub-band;

Step 103: Calculate the equivalent SINR of each subband of the user equipment as SINR _sub = SINR _MCS + ΔSINR _sub ;

Step 104: Select a modulation and coding strategy MCS in frequency selective scheduling according to the equivalent signal-to-interference-noise ratio of each subband of the user equipment.

In order to make the technical principles, features and technical effects of the technical solution of the present application clearer, the technical solution of the present application will be described in detail below in conjunction with specific embodiments.

The implementation process of the downlink frequency selection scheduling method provided by a preferred embodiment of the present application is shown in Figure 2, including the following steps:

Step 201: The base station side dynamically adjusts the wideband SINR _MCS according to the ACK/NACK information first transmitted by the user.

Another embodiment of the present application provides an implementation manner of dynamically adjusting the wideband SINR _MCS :

The user receives the physical downlink shared channel (PDSCH) information transmitted for the first time. If the information is fed back with an acknowledgment (ACK), the current wideband SINR _MCS is adjusted up by an ascending step value Δ _up , that is, SINR _MCS = SINR _MCS + Δ _up ; and if the negative response NACK is fed back to the PDSCH information, the current broadband SINR _MCS is lowered by a down step value Δ _down , that is, SINR _MCS =SINR _MCS -Δ _down , where Δ _up /Δ _down =bler/(1 -bler). A preferred value range of the down step value Δ _down is (0,1]dB.

Step 202: the base station counts the wideband CQI reported by the UE, and converts the wideband CQI statistical value into an equivalent SINR threshold SINR _CQI .

The base station side makes statistics on the periodic (or non-periodic) broadband CQI reported by the UE (it can count the broadband CQI within a certain period of time T or the statistics of N broadband CQI reported continuously), and then convert it into the corresponding solution after obtaining the statistical value Adjust the SINR threshold SINR _CQI .

Those skilled in the art should know that there is a definite correspondence between the wideband CQI and the threshold SINR _CQI for demodulating the SINR. A simple implementation method is as follows: the base station side saves the correspondence table between the wideband CQI and the threshold SINR _CQI for demodulating the SINR, and the base station side obtains that the average wideband CQI statistical value within a certain period of time T is M, and then queries the correspondence table to obtain the corresponding Threshold SINR _CQI for demodulating SINR.

Step 203: Determine whether the change trend of the wideband SINR _MCS and the equivalent SINR threshold SINR _CQI are consistent, if consistent, that is, the SINR _MCS is on the rise and the SINR _CQI is greater than the SINR _MCS , or the SINR _MCS is on the decline and the SINR _CQI is less than SINR _{MCS goes} to step 204, otherwise executes step 205.

Step 204: Adjust SINR _MCS according to the equivalent SINR information.

Another embodiment of the present application provides a specific implementation of adjusting the SINR _MCS : adjust the SINR _MCS according to the following formula,

SINR _MCS = SINR _MCS × alfa + SINR _CQI × (1-alfa), where alfa is a filter factor, which can be set.

Step 205: Construct a sub-band SINR _MCS for frequency selective scheduling according to the currently obtained SINR _MCS and the sub-band differential CQI reported by the UE. Specifically: first convert the sub-band differential CQI into the difference ΔSINR _sub of the corresponding SINR, and then calculate the equivalent SINR sub of each sub-band as SINR _sub = SINR _MCS + ΔSINR _sub to be used in frequency selection scheduling MCS selection.

The above descriptions are only preferred embodiments of the application, and are not intended to limit the scope of protection of the application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the technical solutions of the application are It should be included within the protection scope of this application.

Claims (5)

1. a downlink frequency selection scheduling method, is characterized in that, comprising:

The broadband Signal to Interference plus Noise Ratio SINR of A, base station calculating subscriber equipment _mCS;

The subband differential channel quality of user equipment to report instruction CQI is converted to the Signal to Interference plus Noise Ratio difference DELTA SINR of corresponding subband by B, base station _sub;

The equivalent Signal to Interference plus Noise Ratio of C, each subband of calculating subscriber equipment is SINR _sub=SINR _mCS+ Δ SINR _sub;

D, to select modulation in selection scheduling frequently and coding strategy MCS according to the equivalent Signal to Interference plus Noise Ratio of each subband of subscriber equipment.

2. method according to claim 1, is characterized in that, steps A comprises:

A1, base station side pass ACK/NACK information dynamic conditioning subscriber equipment broadband Signal to Interference plus Noise Ratio SINR according to subscriber equipment head _mCS;

The broadband CQI that A2, base station counting user equipment report, is converted to equivalent SINR thresholding SINR by broadband CQI statistical value _cQI;

A3, judge broadband Signal to Interference plus Noise Ratio SINR _mCSwith equivalent SINR thresholding SINR _cQIvariation tendency whether consistent, if unanimously, proceed to steps A 4, otherwise go to step B;

A4, according to described equivalent SINR thresholding SINR _cQIadjustment broadband Signal to Interference plus Noise Ratio SINR _mCS.

3. method according to claim 2, is characterized in that, steps A 1 comprises: subscriber equipment receives the Physical Downlink Shared Channel information transmitted first, if to this information feed back affirmative acknowledgement ACK, then to current broadband SINR _mCSraise a step up value Δ _up, i.e. SINR _mCS=SINR _mCS+ Δ _up; If to this PDSCH information feed back negative response NACK, then to current broadband SINR _mCSlower a decline step value Δ _down, i.e. SINR _mCS=SINR _mCS-Δ _down, wherein Δ _up/ Δ _down=bler/ (1-bler).

4. method according to claim 3, is characterized in that, described decline step value Δ _downspan be (0,1] dB.

5. method according to claim 2, is characterized in that, steps A 4 is: according to following formula adjustment broadband Signal to Interference plus Noise Ratio SINR _mCS:

SINR _mCS=SINR _mCS× alfa+SINR _cQI× (1-alfa), wherein alfa is filtering factor.