CN103138909B - A kind of WiMAX system uplink interference level computational methods - Google Patents

Abstract

A kind of WiMAX system uplink interference level computational methods, belong to broadband wireless access field, it is characterized in that, base station side is according to the Region dividing of uplink frame and Time slot allocation situation, utilize pilot sub-carrier to calculate all time slot sub-carrier power respectively, distribute time slot sub-carrier power, thus obtain in up region, unallocated time slot sub-carrier power, by smoothing to the power of present frame and previous frame, obtain the up average noise interference level value of present frame.Up average noise interference level value is sent to terminal by base station, and terminal utilizes this value to calculate up open loop power.This method is applicable to calculate the interference level under various different frame structure situation, is easy to realize simultaneously.

Description

A kind of WiMAX system uplink interference level computational methods

Technical field

The invention belongs to broadband wireless access field.

Background technology

" last one kilometer " problem that solves for a long time depends on cable technology access, and worldwide interoperability for microwave access technology (WiMAX technology) solves the broadband access problem in the area that wired mode cannot cover, data transport service that is real-time, non real-time, different rates requirement can be provided, for wideband data access provides new solution according to service needed.Therefore significant to the research of WiMAX technology.

Taking effective power to control can transmitting power on each subcarrier of dynamic conditioning, energy efficient, system resource can be made to be fully used, improve the capacity of whole communication system and the communication quality of mobile subscriber, therefore the status that controls in WiMAX system of power is of crucial importance

In WiMAX communication system, power controls to be divided into open loop power control and closed-loop power control, and in open loop power control, the transmitting power of each subcarrier of up link is calculated by formula (1)

P(dBm)＝L+C/N+NI-10log(R)+Offset_SS _perSS+Offset_BS _perSS(1)

Wherein, L represents current up path loss; L=BS_EIRP-RSSI _preamble, BS_EIRP launches targeting sequencing (preamble) power when using omnidirectional antenna gain, and BS transmitting power; RSSI _preamblebe the received power of last targeting sequencing, wherein deducted the gain of mobile subscriber terminal receive diversity; C/N definitely expects modulating-coding C/N, and modulation coding mode determines that rear C/N is fixed value; R attach most importance to multiple modulation coding number of times, provided by UL_MAP (up media access protocol).Offset_SS _perSSfor the transmitting power correction value that MS controls, initial value is 0; Offset_BS _perSSthe transmitting power correction value controlled by BS; NI is the average interference level value of each subcarrier that base station side receives.In systems in practice, whether the calculating of NI not yet to appearing computational methods, and accurately can calculate NI to the calculating of power and be applicable to various different frame structure situation and be extremely important.

The present invention will according to uplink frame Region dividing and time slot allocation information, proposition utilizes pilot sub-carrier to calculate all time slot sub-carrier power respectively, distribute time slot sub-carrier power, thus obtain in up region, unappropriated sub-carrier power, by smoothing to the power of present frame and previous frame, obtain the up average noise interference level value of present frame.

Summary of the invention

The object of the present invention is to provide a kind of WiMAX system uplink interference level computational methods, this method is applicable to the service condition of different frequency multiplex mode, multizone, multiple terminals.

Thought of the present invention is: according to uplink frame Region dividing and Time slot allocation situation, pilot sub-carrier is utilized to calculate all time slot sub-carrier power respectively, distribute time slot sub-carrier power, thus obtain in up region, unallocated time slot sub-carrier power, by smoothing to the power of previous frame and present frame, obtain the up average noise interference level value of present frame, whole flow process as shown in Figure 1.

It is characterized in that, be the uplink interference level computational methods that a kind of global microwave internet access system base station side performs, performing step of the present invention is as follows:

Step (1), the structural information of the MAC layer MAC layer collocating uplink frame of base station, comprises bandwidth, lower uplink symbol than Ratio, zoning number, each field frequency multiplex mode, each area data burst allocation number of time slot;

Step (2), base station physical layer obtains the structural information of uplink frame from MAC layer, extract the structural information that sequence number is the current uplink frame of n, comprise: sequence number is the current uplink frame of n, the frequency multiplexing mode in the upgoing O FDM total number of symbols obtained than Ratio from described lower uplink symbol, each region OFDM symbol number, each region and each region allocation subchannel number Sch corresponding with the frequency multiplexing mode in each region _i, i is region sequence number, i=1,2 ..., I, I are maximum area, n=1,2 ..., N, N are maximum up frame number, I and N is what set;

Step (3), the sequence number obtained according to step (2) is the structural information of the current uplink frame of n, is calculated as follows unappropriated timeslot number UnUsedNum in each region _i

Step (4), each region time slot is initial, the rectangular coordinate system of end position for calculating to set up one: take sequence number as the current uplink frame OFDM symbol number time domain direction of n be X-axis, with number of subchannels Sch _idirection is Y-axis, with the time slot abscissa X along X-direction _schreplace the OFDM symbol sequence number corresponding to X-axis, namely x _ch=0 .x _sch., X _max, the origin of coordinates is located at the starting point of first time slot in region 1, and first time slot origin coordinates is (0,0), and first time slot end coordinate is (1,0), and the end coordinate of each time slot is (x _ch, y), the end coordinate of last time slot is

Step (5), is calculated as follows s in the i of region _ithe mean pilot sub carrier power P wr of individual time slot _i,s, i.e. time slot power, wherein: Pilot _s,urepresent that sequence number is u pilot sub-carrier power in the time slot of s, U is pilot sub-carrier sum in time slot, and fixed value is 24, and sequence number s is calculated as follows s=x _schsch _i+ y;

Step (6), utilizes the mean pilot sub carrier power P wr of each time slot in the region i obtained in step (5) _i,scalculate all time slot S in described region i _imean pilot sub carrier power SumPwr _i:

Step (7), is calculated as follows data burst in the i of region and distributes the mean pilot sub carrier power UsedPwr of time slot _i: wherein S ' _irepresent that region i data burst distributes number of time slot, S ' _i=1,2 ..., s ' _i..., S _i, and S ' _i≤ S _i;

Step (8), is calculated as follows the mean pilot sub carrier power of unallocated time slot in the i of region namely the noise jamming level in the i of region, uses NI _in () represents;

Step (9), makes smoothing computation by following formula, obtains the average noise interference level NI that sequence number is region i in the current uplink frame of n _{i, avg}(n)=10log (α NI _i(n)+(1-α) NI _{i, avg}(n-1)), wherein α=1/16, if the average noise interference level of the former frame of initial calculation first uplink frame, namely sequence number is the average noise interference level NI of the uplink frame of 0 _{i, avg}(0)=0, therefore NI _{i, avg}(1)=10log (α NI _i(1));

Step (10), repeats step (3) ~ step (9), obtains the average noise interference level NI that sequence number is each region i in the current uplink frame of n _{i, avg}(n), i=1,2 ..., I.

Feature of the present invention, the calculating of uplink interference level when being applicable to different frequency multiplex mode, multizone, multiple terminals situation, be illustrated in figure 2 uplink frame structure chart when frequency multiplexing mode is resue1, i.e. general uplink frame structure chart, be illustrated in figure 4 a kind of multizone uplink frame structure chart, be illustrated in figure 6 the situation that frequency multiplexing mode is resue3 frame structure, this method is all suitable for.

Accompanying drawing explanation

Fig. 1 algorithm flow chart.

The general uplink frame structure chart of Fig. 2.

Fig. 3 data burst time slot allocation figure: distribute time slot, unallocated time slot.

Fig. 4 multizone uplink frame structure chart.

Fig. 5 multizone data burst time slot allocation figure: distribute time slot, unallocated time slot.

Fig. 6 frequency multiplexing mode is reuse3 structure chart.

Embodiment

Below in conjunction with accompanying drawing, the invention will be further described.

Embodiment one

Refer to the general uplink frame structure chart of Fig. 2, be illustrated in figure 3 data burst Time slot allocation situation, NI is described _{i, avg}n implementation step that () calculates,

Step (1), the structural information of the MAC layer MAC layer collocating uplink frame of base station, comprise bandwidth 5MHz, lower uplink symbol than Ratio be 23:24, zoning number is 1, to distribute number of time slot be 9 for region 1 frequency multiplexing mode reuse1, region 1 data burst;

Step (2), base station physical layer obtains the structural information of uplink frame from MAC layer, extract the structural information that sequence number is the current uplink frame of n, comprise: sequence number is the current uplink frame of n, from described lower uplink symbol than the upgoing O FDM total number of symbols that Ratio obtains be 24, the OFDM symbol number of the distribute data in region 1 burst is 24, the frequency multiplexing mode in region 1 is reuse1, region 1 allocated sub-channels number Sch ₁be 17;

Step (3), the sequence number obtained according to step (2) is the structural information of the current uplink frame of n, is calculated as follows unappropriated timeslot number UnUsedNum in each region ₁:

Step (4), set up the rectangular coordinate system of a, end position initial for zoning 1 time slot: take sequence number as the current uplink frame OFDM symbol number time domain direction of n be X-axis, with number of subchannels Sch direction for Y-axis, in this application, with the time slot abscissa X along X-direction _schreplace the OFDM symbol sequence number corresponding to X, namely i.e. X _sch=0,1,2 ..., 7, the origin of coordinates is located at the starting point of first time slot in region 1, and first time slot origin coordinates is (0,0), first time slot end coordinate is (1,0), and the end coordinate of last time slot is (7,16);

Step (5), is calculated as follows s in region 1 ₁the mean pilot sub carrier power P wr of individual time slot _{1, s}, i.e. time slot power, wherein: Pilot _s,urepresent that sequence number is u pilot sub-carrier power in the time slot of s, sequence number s is calculated as follows s=x _schsch _i+ y;

Step (6), utilizes the mean pilot sub carrier power P wr of each time slot in the region 1 obtained in step (5) _{1, s}calculate all time slot S in described region 1 ₁mean pilot sub carrier power SumPwr ₁: namely ${\mathrm{SumPwr}}_1=\frac{1}{119}\underset{s=0}{\overset{118}{\Σ}}{\mathrm{Pwr}}_{1,s};$

Step (7), is calculated as follows data burst in region 1 and distributes the mean pilot sub carrier power UsedPwr of time slot ₁: s ' ₁represent that region 1 data burst distributes number of time slot S ' ₁=9, therefore ${\mathrm{UsedPwr}}_1=\frac{1}{S_1^{\′}}\underset{s=0}{\overset{S_1^{\′}-1}{\Σ}}{\mathrm{Pwr}}_{1,s}=\frac{1}{9}\underset{s=0}{\overset{8}{\Σ}}{\mathrm{Pwr}}_{1,s};$

Step (8), is calculated as follows the mean pilot sub carrier power NI of unallocated time slot in region 1 _{1, (119-9)}: NI _{1, (110)}=SumPwr ₁-UsedPwr ₁, the noise jamming level namely in region 1, i.e. NI _i(n);

Step (9), makes smoothing computation by following formula, obtains the average noise interference level NI that sequence number is region 1 in the current uplink frame of n _{1, avg}(n)=10log (α NI ₁(n)+(1-α) NI _{1, avg}(n-1)), wherein α=1/16, if the former frame average noise interference level of initial calculation first uplink frame, namely sequence number is the average noise interference level NI of the uplink frame of 0 _{1, avg}(0)=0, i.e. NI _{1, avg}(1)=10log (α NI ₁(1)).

Embodiment two

Refer to Fig. 4 multizone uplink frame structure chart, be illustrated in figure 5 multizone data burst time slot allocation figure so that NI to be described _{i, avg}n implementation step that () calculates,

Step (1), the structural information of the MAC layer MAC layer collocating uplink frame of base station, comprise bandwidth 5MHz, lower uplink symbol than Ratio be 23:24, zoning number is 2, region 1 frequency multiplexing mode reuse3, region 2 frequency multiplexing mode reuse1, region 1 data burst distribute that number of time slot is 0, to distribute number of time slot be 9 to region 2 data burst;

Step (2), base station physical layer obtains the structural information of uplink frame from MAC layer, extract the structural information that sequence number is the current uplink frame of n, comprise: sequence number is the current uplink frame of n, from described lower uplink symbol than the upgoing O FDM total number of symbols that Ratio obtains be 24, the OFDM symbol number of the distribute data in region 1 burst is 9, the OFDM symbol number of the distribute data in region 2 burst is 9, the frequency multiplexing mode in region 1 is reuse3 therefore region 1 allocated sub-channels number Sch ₁be 6, the frequency multiplexing mode in region 2 is reuse1 therefore region 2 allocated sub-channels number Sch ₂be 17;

Step (3), the sequence number obtained according to step (2) is the structural information of the current uplink frame of n, is calculated as follows unappropriated timeslot number UnUsedNum in each region _i

Step (4), each region time slot is initial, the rectangular coordinate system of end position for calculating to set up one: take sequence number as the current uplink frame OFDM symbol number time domain direction of n be X-axis, with number of subchannels Sch direction for Y-axis, in this application, with the time slot abscissa X along X-direction _schreplace the OFDM symbol sequence number corresponding to X, x _sch=0 .x _sch., X _max, i.e. X _sch=0,1,2, the origin of coordinates is located at the starting point of first time slot in region 1, and first time slot origin coordinates is (0,0), and first time slot end coordinate is (1,0), and last time slot end coordinate of region 1 is (3,5);

Step (5), is calculated as follows s in the i of region _ithe mean pilot sub carrier power P wr of individual time slot _i,s, i.e. time slot power, wherein: Pilot _s,urepresent that sequence number is u pilot sub-carrier power in the time slot of s, sequence number s is calculated as follows s=x _schsch _i+ y;

Step (6), utilizes the mean pilot sub carrier power P wr of each time slot in the region i obtained in step (5) _i,scalculate all time slot S in described region i _imean pilot sub carrier power SumPwr _i: namely ${\mathrm{SumPwr}}_1=\frac{1}{18}\underset{s=0}{\overset{17}{\Σ}}{\mathrm{Pwr}}_{1,s};$

Step (7), is calculated as follows data burst in the i of region and distributes the mean pilot sub carrier power UsedPwr of time slot _i: s ' ₁represent that region 1 data burst distributes number of time slot S ' ₁=0, therefore UsedPwr ₁=0;

Step (8), is calculated as follows the mean pilot sub carrier power of unallocated time slot in region 1 nI _{1, (18)}=SumPwr ₁-UsedPwr ₁=SumPwr ₁, the noise jamming level namely in region 1, i.e. NI ₁(n);

Step (9), makes smoothing computation by following formula, obtains the average noise interference level NI that sequence number is region 1 in the current uplink frame of n _{1, avg}(n)=10log (α NI ₁(n)+(1-α) NI _{1, avg}(n-1)), wherein α=1/16, if the former frame average noise interference level of initial calculation first uplink frame, namely sequence number is the average noise interference level NI of the uplink frame of 0 _{1, avg}(0)=0, i.e. NI _{1, avg}(1)=10log (α NI ₁(1)).

Step (10), repeats the average noise interference level of step (3) ~ step (9) zoning 2, the noise jamming level NI in region 2 ₂(n)=NI _{2, (9)}=SumPwr ₂-UsedPwr ₂, wherein ${\mathrm{UsedPwr}}_2=\frac{1}{9}\underset{s=0}{\overset{S_2^{\′}-1}{\Σ}}{\mathrm{Pwr}}_{2,s}=\frac{1}{9}\underset{s=0}{\overset{8}{\Σ}}{\mathrm{Pwr}}_{2,s}$

Claims (1)

1. WiMAX system uplink interference level computational methods, is characterized in that, are the uplink interference level computational methods that a kind of global microwave internet access system base station side performs, have following performing step successively:

Step (1), the structural information of the MAC layer MAC layer collocating uplink frame of base station, comprises bandwidth, lower uplink symbol than Ratio, zoning number, each field frequency multiplex mode, each area data burst allocation number of time slot;

Step (2), base station physical layer obtains the structural information of uplink frame from MAC layer, extract the structural information that sequence number is the current uplink frame of n, comprise: sequence number is the current uplink frame of n, the frequency multiplexing mode in the upgoing O FDM total number of symbols obtained than Ratio from described lower uplink symbol, each region OFDM symbol number, each region and each region allocation subchannel number Sch corresponding with the frequency multiplexing mode in each region _i, i is region sequence number, i=1,2 ..., I, I are maximum area, n=1,2 ..., N, N are maximum up frame number, I and N is what set;

Step (3), the sequence number obtained according to step (2) is the structural information of the current uplink frame of n, is calculated as follows unappropriated timeslot number UnUsedNum in each region _i

Step (4), each region time slot is initial, the rectangular coordinate system of end position for calculating to set up one: take sequence number as the current uplink frame OFDM symbol number time domain direction of n be X-axis, with number of subchannels Sch _idirection is Y-axis, with the time slot abscissa X along X-direction _schreplace the OFDM symbol sequence number corresponding to X-axis, namely

the origin of coordinates is located at the starting point of first time slot in region 1, and first time slot origin coordinates is (0,0), and first time slot end coordinate is (1,0), and the end coordinate of each time slot is (x _sch, y), the end coordinate of last time slot is

Step (5), is calculated as follows s in the i of region _ithe mean pilot sub carrier power P wr of individual time slot _i,s, i.e. time slot power, wherein: Pilot _s,urepresent that sequence number is u pilot sub-carrier power in the time slot of s, U is pilot sub-carrier sum in time slot, and fixed value is 24, and sequence number s is calculated as follows s=X _schsch _i+ y;

Step (6), utilizes the mean pilot sub carrier power P wr of each time slot in the region i obtained in step (5) _i,scalculate all time slot S in described region i _imean pilot sub carrier power SumPwr _i:

Step (7), is calculated as follows data burst in the i of region and distributes the mean pilot sub carrier power UsedPwr of time slot _i: wherein S ' _irepresent that region i data burst distributes number of time slot, S ' _i=1,2 ..., s ' _i..., S _i, and S ' _i≤ S _i;

Step (8), is calculated as follows the mean pilot sub carrier power of unallocated time slot in the i of region namely the noise jamming level in the i of region, uses NI _in () represents;

Step (9), makes smoothing computation by following formula, obtains the average noise interference level NI that sequence number is region i in the current uplink frame of n _{i, avg}(n)=10log (α NI _i(n)+(1-α) NI _{i, avg}(n-1)), wherein α=1/16, if the average noise interference level of the former frame of initial calculation first uplink frame, namely sequence number is the average noise interference level NI of the uplink frame of 0 _{i, avg}(0)=0, therefore NI _{i, avg}(1)=10log (α NI _i(1));

Step (10), repeats step (3) ~ step (9), obtains the average noise interference level NI that sequence number is each region i in the current uplink frame of n _{i, avg}(n), i=1,2 ..., I.