Method and apparatus of the present invention is highly suitable in the wireless communication system that has used one or more multi-sector cells and uses.What Figure 11 described is example system 1100, has wherein only shown an independent sub-district 1104, but should be appreciated that this system can and comprise numerous these type of sub-districts 1104 usually.It is a plurality of sectors of N that each sub-district 1104 has been divided into quantity, and wherein N is the positive integer greater than 1.And such a case has been described by system 1100, and wherein each sub-district 1104 is subdivided into three sectors: i.e. the first sector S0 1106, the second sector S1 1108 and the 3rd sector S2 1110.Sub-district 1104 has comprised S0/S1 sector borders 1150, S1/S2 sector borders 1152 and S2/S0 sector borders 1154.Concerning sector borders, on said border, can use level much at one to receive the signal that comes from a plurality of sectors, for example adjacent sectors, receiver is difficult to distinguishing from the transmission of sector, place and from the transmission of adjacent sectors thus.In the sub-district 1104, a plurality of end nodes (EN) will communicate with base station (BS) 1102, and wherein said end node can be a this wireless terminal of mobile node (WT).The sub-district of two sectors (N=2) and three above sectors (N＞3) might appear having in addition.In sector S0 1106, a plurality of end node EN (1) 1116, EN (X) 1118 are coupled to base station 1 1102 via Radio Link 1117,1119 respectively.In sector S1 1108, a plurality of end node EN (1 ') 1120, EN (X ') 1122 are coupled to base station 1 1102 via Radio Link 1121,1123 respectively.S2 1110 in the sector, and a plurality of end node EN (1 ") 1124, EN (X ") 1126 are coupled to base station 1 1102 via Radio Link 1125,1127 respectively.According to the present invention; Base station 1102 uses a plurality of power levels that pilot signal transmission is arrived EN1116,1118,1120,1122,1124,1126, and between three sectors, will carry out synchronously having different predetermined pilot signal transmission with known level.According to the present invention, EN (1) 1116 this type end node can be to base station 1102 report feedback informations, and for example channel quality indicated value makes base station 1102 can confirm the SNR that wireless terminal receives thus, and wherein said SNR is the function of base station transmit signals power.Network node 1112 is coupled to via network link 1114 in base station 1102.1112 of network nodes are coupled to other network nodes via network link 1129, for example intermediate node, other base stations, AAA node, origin agent node or the like and internet.Network node 1112 also provides the interface that is connected to 1104 outsides, sub-district, allows the EN of 1104 inside in the sub-district and sub-district 1104 outside peer node to communicate thus.The inner EN in sub-district 1104 can be in the sub-district inside of 1104 sector 1106,1108,1110 move, also can move to and corresponding another sub-district, another base station.In addition, for instance, network link 1114 and 1129 can also be fiber optic cables.
What Figure 12 described is the exemplary base station of implementing according to the present invention (BS) 1200.Base station 1200 is expressions more in detail of the base station 1102 that shows in the example communications system 1100 of Figure 11.Base station 1200 has comprised respectively the fan anteena 1203,1205 that is coupled with receiver 1202 and transmitter 1204.Receiver 1202 comprises decoder 1212, and transmitter 1204 then comprises encoder 1214.In addition, base station 1200 also comprises processor 1206 and the memory 1210 of I/O interface 1208, CPU and so on.And transmitter 1204 is used to via fan-shaped transmitting antenna 1205 and with the method for synchronization pilot signal transmission arrived a plurality of sectors.Receiver 1202, transmitter 1204, processor 1206, I/O interface 1208 and memory 1210 are coupled via bus 1209, wherein different parts can be on said bus swap data and information.I/O interface 1208 then is coupled to internet and other network nodes with base station 1200.
Memory 1210 comprises program 1218 and data/information 1220.When being carried out by processor 1206, program 1218 makes base station 1200 come executable operations according to the present invention.Program 1218 comprises signal procedure 1222, receives signal handler 1260 and base station control program 1224.Receive signal handler 1260 and comprised the channel quality indicated value extraction module 1262 that is used for extracting channel quality indicated value, and be used for extracting the positional information extraction module 1264 of WT positional information from receiving message from this type of report message reception signal of WT.In certain embodiments, the positional information indication is the position of WT with respect to sector borders.The channel quality indicated value that SNR or this type of performance number are extracted then offers transmit power calculation program 1226, so that in for the process of calculated signals through-put power that is sent to WT, use.Base station control program 1224 comprises scheduler module 1225, transmit power calculation program 1226 and signaling procedure 1228, and wherein said signaling procedure 1228 has comprised pilot signal and produced and transmission control procedure.
Data/information 1220 comprises data 1232, pilot tone hopping sequences information 1234 and wireless terminal data/information 1240.Data 1232 can comprise the data from receiver decoder 1212, are about to send to the data of transmitter coding device 1214, result of intermediate process steps or the like.1234 of pilot tone hopping sequences information comprise power level information 1236 and tone information 1238.According to the present invention, power level information has defined the different power level in pilot tones hopping sequences inside, and these power levels will be applied to different tones, so that produce the pilot tone of varying strength.Wherein for instance, before transmission, these pilot value will be configured to the fixed value of preliminary election, and the inner WT in the sub-district that BS1200 and BS1200 served knows these pilot value.Inner with the pilot tones hopping sequences of each Termination ID 1246 corresponding each sectors; Tone information 1238 has comprised the information that is used to stipulate following content; These contents comprise: with the pilot tones of which tone as the certain strength grade, which tone is that sectors zero tone and which tone should be sub-district zero tones.Wireless terminal data/information 1240 has comprised the corresponding data message set of each wireless terminal inner with being operated in the sub-district, the i.e. information 1254 of the information 1242 of WT1, WT N.Concerning the information 1242 of each ensemble of communication, for example WT1, this information set has comprised data 1244, Termination ID 1246, sector ID 1248, channel quality indicated value 1250 and sector borders positional information 1252.1244 of data have comprised from the user data of WT1 reception and the user data that will be sent to the peer node that communicates with WT1.Termination ID 1246 is the signs by base station assigns, and this sign has been distributed to WT1 here; In addition, will produce specific pilot tones hopping sequences with each corresponding base station of particular terminal ID1246, this sequence has comprised the pilot signal that is in different time and has varying strength.
Which the sector work of 1248 couples of WT1 of sector ID in three sector S0, S1, S2 is discerned.Channel quality indicated value 1250 has comprised WT1 and has sent the information of base station to through channel quality report messages, and the base station can use this message to calculate the expection SNR grade that on WT1, receives as base station transmits signal power function.According to the present invention, channel quality indicated value 1250 is to be derived from its measurement that pilot signal of the varying strength of base station is carried out by WT1.Sector borders positional information 1252 then comprises: be used to discern WT1 and whether detect it near certain sector borders and meet with the very information of interference levels thus, and to be used to discern approaching be the information of which sector borders WT1.This information is to obtain the position feedback information that receives from WT1 emission and by BS and derive.1252 expressions of channel quality indicated value 1250 and sector borders positional information be 1200 channel quality feedback information from WT1 to the base station, the information about one or more downlink channel between base station 1200 and the WT1 is provided thus.
Signal procedure 1222 is used to control base station 1200, so that carry out different traffic operations and realize different communication protocol.Base station control program 1224 is used to control base station 1200; So that carry out basic base station functions; For example produce and receive the method step of signal, scheduling and embodiment of the present invention, this is comprising the information that produces pilot signal and reception, processing and the report of use wireless terminal with different intensity transmission grades.1228 pairs of signaling procedures are used to produce and detect the transmitter 1204 of the signal of travelling to and fro between wireless terminal to be controlled with receiver 1204, and wherein said signal can be the ofdm signal of data-driven tone hopping sequences.Pilot signal produces and transmission control procedure uses the data/information 1220 that has comprised pilot tone hopping sequences information 1234 to produce specific pilot tones hopping sequences for each sector.Produce the guide with transmission control procedure 1230 by means of pilot signal, the specific tone that can select to the pilot tones power level that comprises in the power level information 1236 and for the special pilot tone of each pilot tone in each sector of special time reception is coordinated and is controlled.Shown in Figure 15～17,1230 pairs of pilot tones transmission of program are controlled.The dedicated processes instruction of being responsible for the different pilot tones of transmission such as this type of software command can be independent assembly or module; Here can these assemblies and module be construed to is independent device, and these devices control the base station through cooperation so that the pilot tones sequence of describing and showing in emission Figure 15～17.For example; In control transmission power; Through transmission frequency and/or code element transmission time aspect these to cell sector between dissimilar pilot signal transmission coordinate and/or synchronously; Can make wireless terminal receive the emission pilot tones of varying level, the pilot tones of for example known and predetermined fixed level, sectors zero pilot tones and sub-district zero pilot tones can from the measured signal value, obtain channel quality indicated value 1250 through the operation of calculating and so on thus.According to the present invention, conventional (non-zero) pilot tones, sectors zero pilot tones and sub-district zero pilot tones can be punchinged or replace said data tones the data tones of common emission.Scheduler module 1225 is used for control transmission scheduling and/or communication resource distribution.According to the present invention, can be provided for indicating the information of the SNR that each wireless terminal receives here for scheduler 1225, wherein said SNR is the function of base station transmit signals power.Scheduler can use this information that from channel quality indicated value 1250, derives to come the assignment channel segment as WT.So then allow BS1200 to distribute channel segmentation, so that satisfied particular data rate, encoding scheme and/or the selected modulation scheme that offers WT is for the needs that receive SNR with capacity through-put power.
What Figure 13 described is the exemplary wireless terminal of implementing according to the present invention 1300.Wireless terminal 1300 can be used as wireless end node, for example mobile node.Said wireless terminal 1300 is the EN1114,1116,1118,1120,1122 that shows in the example communications system 1100 of Figure 11,1124 expression more in detail.This wireless terminal 1300 has comprised receiver 1302, transmitter 1304, the processor such as CPU 1306 and memory 1308, and these parts are coupled through bus 1310, and these assemblies can be on bus swap data and information.Wireless terminal 1300 comprises respectively the Receiver And Transmitter antenna 1303,1305 that is coupled with Receiver And Transmitter 1302,1304.Receiver 1302 comprises decoder 1312, and 1304 in transmitter comprises encoder 1314.Processor 1306 is controlled by one or more programs 1320 of storage in the memory 1308, so that wireless terminal 1300 comes executable operations according to inventive method described herein.Program 1320 and data/information 1322 have been comprised in the memory 1320.Program 1320 comprises signal procedure 1324 and wireless terminal control program 1326.Wireless terminal control program 1326 comprises signaling procedure 1328, and wherein said signaling procedure 1328 comprises pilot signal measurement module 1330, channel quality indicated value generation module 1332, sector borders position determination module 1331 and channel quality indicated value transmission control module 1333.Data/information 1322 comprises user data 1334, user profile 1336 and pilot tone signaling information 1350, and wherein said user data 1334 can be the information that soon will be transmitted into peer node from wireless terminal 1300.User profile 1336 comprises measured signal value information 1337, quality indicated value information 1338, sector borders positional information 1340, Termination ID information 1342, base station IDs information and channel report information 1346.Pilot tone signaling information 1350 comprises hopping sequences information 1352, power level information 1354 and tone information 1356.Measured signal value information 1337 comprises the measured signal value, and wherein said measured signal value is under the control of pilot signal measurement module 1330, in the amplitude through measure receiving pilot signal and the phase place at least one and quilt is obtained.Quality indicated value information 1338 has comprised the output of channel quality indicated value generation module 1332.When channel quality indicated value information 1338 was sent to the base station, this information allowed base station to confirm as transmitted signal power function and the SNR that received by WT.1340 of sector borders positional informations comprise and are used for the information that identified wireless terminal is in certain sector boundary regions; Wherein for instance; This information can be to show that wireless terminal suffers from the information of very high inter-sector interference level; In addition, said sector borders positional information 1340 comprises that also which sector that is used for discerning these two adjacent sectors is the information of borderline region sector.The base station can use sector borders information to discern should stop through-put power to reduce the channel of inter-sector interference in the adjacent sectors.Channel report information 1346 has comprised quality channel indicated value 1338 or a part of channel quality indicated value 1338 that is obtained, and can comprise sector borders positional information 1340 in addition.Channel report information 1346 can be used corresponding to the corresponding message of each quality indicated value and construct, and also can construct with the quality indicated value group that comprises in the single message.And these message are periodically seen off at the fixed time and on the dedicated channel.When the cellular coverage internal work of wireless terminal 1300 in the base station, being by base station assigns and being applied to the information of wireless terminal 1300 of Termination ID information 1342 expressions.Base station IDs information 1344 has comprised the base station relevant information, the slope value of hopping sequences for example, and in addition, said base station IDs information can also comprise sector mark information.
When pilot tone hopping sequences information 1352 should measure which tone 1356 for the specific base identification with base station IDs information 1344, so that the assessment pilot signal, wherein said tone can be the OFDM symbol time.1354 of pilot signal power level information discern the pilot signal transmission level on the pilot signal tone 1356 that distributes that comprises in the pilot tones hopping sequences 1352 to wireless terminal.In addition, pilot signal power level information 1354 can also be discerned sector and sub-district zero pilot tones.
Signal procedure 1324 is used to control wireless terminal 1300, so that carry out different traffic operations and implement different communication protocol.
Wireless terminal control program 1326 is controlled the basic function of wireless terminal 1300 according to method of the present invention.The basic function of 1328 pairs of wireless terminal signalings of wireless terminal signaling procedure is controlled; Generation and reception comprising receiver control 1302, transmitter 1304 and signal; In addition; The wireless terminal signaling procedure is also controlled the operation of wireless terminal according to method of the present invention, these operations comprise: measurement pilot signals, generation quality indicated value and transmission channel quality indicated value.1330 pairs of measurements that receive pilot signal of pilot signal measurement module are controlled, and wherein this signal is with base station IDs information 1344, hopping sequences information 1352 and tone information 1356 signs.In addition, pilot signal measurement program 1330 is gone back at least one in measurement pilot signals amplitude and the phase place, so that produce and the measured corresponding measured signal value of each pilot signal.Channel quality indicated value generation module 1332 comprises power estimation module 1361 and SNR estimation module 1362.Said channel quality indicated value generation module 1332 produces quality indicated value according to the function of the measured signal value 1337 of having used pilot signal measurement module 1330 outputs.In addition, this module 1332 also comprises first and second instruction sets, so that realize the first and second channel quality indicated value functions, wherein first function is different from second function.Power estimation module 1361 has comprised software instruction, and this software instruction is controlled processor 1306, so that estimate the received power of one or more reception pilot signals.SNR estimation module 1362 comprises software instruction equally, and this instruction controls processor 1306, so that estimate the signal to noise ratio of one or more reception pilot signals.The information that sector borders position determination module 1331 comprises from receive signal is confirmed the position of wireless terminal 1300 with respect to sector borders.And said sector borders position determination module 1331 can also pick out wireless terminal more can produce bigger interference level to WT1300 near which adjacent sectors border and which adjacent sectors.In addition, the information of sector borders position determination module 1131 outputs will be included in the sector borders positional information 1340.The operation of channel quality indicated value transmission control procedure 1333 subtend base station delivery quality channel indicated value information and sector borders information is controlled.Said channel quality indicated value transmission control procedure 1333 comprises message generating module 1335.And said message generating module 1335 uses machine-executable instruction to come processor controls 1306, so that produce the message that is used to transmit channel quality indicated value.In addition, message generating module 1335 can also produce the message with single channel quality indicated value, perhaps is included at least two channel quality indicated values in the single message.In addition, message generating module 1335 can also produce the message that comprises positional information, and for example the sector borders positional information 1340, and this module can merge to said information in the message that comprises channel quality indicated value.The message that message generating module 1335 produces is under the control of channel quality indicated value transmission control 1333, to launch.Here can interweave, for example substitute said message in turn, so that transmit to those and first and second corresponding message of value.In certain embodiments, channel quality transmission control module 1333 periodically uses the special-purpose communication channel segmentation of transfer channel quality indicated value to launch message.In addition, this module 1333 can also control transmission times, so that should the time consistent with the preliminary election dedicated time slot that the base station provides and used by WT1300, stop other this dedicated time slots of wireless terminals use thus.
Fig. 1 is one and has shown the sketch that is used for the transmitter that present invention is described 101 and receiver 103.For instance, transmitter 101 can be the transmitter 1204 of base station 1200, and receiver 103 can be the receiver 1302 of wireless terminal 1300.With system 100 is example, and in this communication system, transmitter 101 often needs to select appropriate method to come to receiver 103 emission data.These selections comprise: the code rate of error correcting code, modulation constellation ideograph, and transmitted power level.In general, as far as transmitter 101,, comparatively it is desirable to understand from transmitter 101 to receiver 103 communication channel in order to make wise selection.In the example system 100 that Fig. 1 shows, transmitter 101 sends data service 102 to receiver 103 on forward link 105.103 of receivers are reporting to transmitter 101 with forward link channel state 106 from receiver 103 to transmitter on 101 the reverse link 107.Then, transmitter 101 uses the channel condition information 106 appropriate setup parameters of being reported, so that carry out transmission.
What Fig. 2 showed is exemplary wireless cellular system 200; In this system, transmitter is included in the base station (BS) 201 with antenna 205, and receiver is included in the wireless terminal (WT) 203 with antenna 207; So; Base station 201 can communicate information to wireless terminal 203 on one or more downlink channel 208, wherein said wireless terminal can be a portable terminal, also can be fixed terminal.BS201 is through regular meeting's emission pilot signal 209, and this signal is normally launched on the sub-fraction transfer resource, and this signal has comprised known (being scheduled to) code element of using the firm power emission usually.WT 203 measures downlink channel status 213 according to the pilot signal 209 that receives, and through uplink channel 215 channel status 213 is reported to BS201.Should be noted that; Channel status 213 usually can be because of decay and Doppler effect and is changed in time, therefore, comparatively it is desirable to; BS 201 frequently and even continuously launches pilot tone 209; So, when channel status 213 changed in time, WT 203 can follow the trail of and reporting channel state 213.And WT 203 can come estimating down-ward link channel state 213 with interference according to the noise that receives on signal strength signal intensity and the pilot signal 209.Will call " noise/interference " to the combination of noise and interference hereinafter, then only be referred to as " noise " sometimes.In the prior art, this information is normally measured the form report with this single scalar of signal to noise ratio (snr) than form or of equal value.If noise/interference and transmission signals are irrelevant, this single scalar measures usually how to change needed full detail with the signal transmitting power in order to prediction reception SNR on BS201 exactly so.In this case, BS201 can be that its selected coding that is used to launch and modulation scheme are confirmed correct (minimum) transmitting power from independent reception value.Yet unfortunately, as far as many sectors, the noise that transmission signals produces might be a very big signal component, will cause single scalar value to be not enough to the SNR of the different transmission power levels of accurately predicting thus.
In the such cellular wireless system of a lot of communication conditions, many sector system especially of the present invention 1100, noise is not independent of channel emission power, but depends on said power.In noise, have the component of " self noise " by name usually, this component and signal power are proportional or roughly proportional.Fig. 3 has shown that a noise depends on the instance of signal transmission power.In Fig. 3, chart 300 shows is correlation reception signal power and the relation of the overall noise on the transverse axis 303 on the longitudinal axis 317.Wherein overall noise is represented with straight line 305, said overall noise be with the part 309 of signal correction and with the summation of the irrelevant part 307 of signal, and here be that relative received signal power 317 is drawn overall noise.Self noise have a multiple reason.One of them self noise instance is to disturb the unbalanced signal energy that receives signal.This noise and signal strength signal intensity are proportional.This unbalanced signal energy might be because of channel estimation errors or the equalizer coefficients error causes, and also might produce because of other reasons in addition.When self noise can be compared perhaps greater than these noises with those noises that is independent of signal, down link SNR value (can on pilot tone, the record) deficiency of single scalar went up the reception SNR as the signal transmission power function so that BS1200 correctly dopes WT1300.
The invention provides a kind of method and apparatus; If there is noise 309 with signal correction; So said method and apparatus can make on its down link of each WT1300 prediction the reception SNR as the signal transmission power function, and allows each WT1300 that this information is delivered to BS1200.So then make BS1200 to come WT is carried out firing operation with different (minimum) signal powers according to the needed corresponding SNR of each WT.Total transmitting power of BS1200 is normally known or fixing, but the ratio of distributing to different WT1300 then can be different, and said ratio can change in time.As shown in Figure 3, on WT receiver 1302, for for the overall noise 303 of the function of received signal power 317, its correlation can be used straight line 305 simulations, and in this application this straight line is called " noise characteristic line ".Because noise characteristic line 305 can not pass through initial point usually, therefore single scalar parameter is not enough to characterize this straight line 305.In order to confirm this line 305, need for example two two parameters that channel quality indicated value is so at least.It is to confirm the position of two dissimilaritys on the said straight line that a kind of straightforward procedure that is used for definite this straight line is arranged, and for example puts 311 and 315, and this is because any two different points all can unique definite straight line.Should be noted that these points are actually with limited accuracy to be confirmed, therefore, compare with the situation that the point of selecting is close together, if the point of selecting relatively away from, so will be higher in order to the precision of confirming said straight line.
Pilot signal is launched in base station 1200 on down link.According to the present invention,, can confirm the noise characteristic line of wireless terminal through the pilot signal of emission different intensity grades.Usually, first pilot signal is sent with first power level, can obtain first point thus, and second pilot signal then is with second power level different with first power level, can obtain second data points thus.In addition, if used different tones, so also can launch first and second pilot tones simultaneously for each pilot signal.
According to Fig. 3, through measuring and handling first pilot signal, can produce first point on the straight line 305, wherein said straight line will be discerned pilot power 317 and the corresponding overall noise level 319 that receives.According to one embodiment of the present of invention, except the non-zero pilot tone, BS1200 also can launch " zero pilot tone " signal on down link.Zero pilot tone has comprised the not transfer resource of transmit signal power (degree of freedom) of BS, and for example the base station is in order to the resource of emission zero energy pilot signal.Second pilot signal as zero pilot signal will produce the point 317 on the straight line 305, and identification zero pilot noise level 313, and wherein said zero pilot noise level 313 is equivalent to those noises 307 that has nothing to do with signal.According to the noise that on pilot tone and zero pilot tone, records, WT1300 can obtain two different Noise Estimation 313,315 that are in unlike signal power, and wherein these two various signals power can be zero energys and receive pilot power 317.In addition, WT1300 can also confirm the complete noise characteristic line 305 among Fig. 3 from these two points 311,315.Then; WT1300 can be with the parameter of this straight line 305 (for example slope and intersection point; Or other equivalent information collection) be delivered to BS1200, so that BS1200 can be the definite SNR of reception of transmit signal power of appointment in to the WT1300 execution firing operation of having reported a plurality of channel quality value.Because it is zero signal power that zero pilot tone has size; And on the other hand; Other pilot tones are normally with relatively large power emission; Therefore these two with Fig. 3 in zero pilot tone and the corresponding point 311,315 of non-zero pilot tone will be relatively away from, in the process of sign line 305, obtain very high precision thus.
To further discuss the problem of signal noise and different signalings now.Chart 400 among Fig. 4 is described is the relation between the overall noise on coherent signal received power and the transverse axis 403 on the longitudinal axis 401.And in Fig. 4, provided the illustration of exemplary noise characteristic line 405.According to the present invention, in order to characterize straight line 405, BS1200 will transmit; So that WT1300 can measure two dissimilaritys on the straight line at least; For example put 407 and 409, then, the information that these obtain from measure is used to characterize straight line 405 will be sent to BS1200.Wherein for instance, BS1200 can launch two various signals power P 1 and P2, and these two signal powers are as the power Y1 that shows among Fig. 4 and Y2 and received.WT1300 measures to the corresponding received signal power represented with Y1415 and Y2419 and with the corresponding overall noise that X1 413 and X2 417 represent respectively.The slope of straight line 405 and intersection point then are well-determined from X1 413, X2 417, Y1 415 and Y2 419.In one embodiment, P1 and P2 are known and fixing.In another embodiment, P2 can be and the corresponding pilot power of pilot signal, and P1 then is the zero point that is used to represent zero-signal, and wherein will to take some through-put power be zero resource to this signal.Yet in general, P1 might not be zero.For example in certain embodiments, P1 can be certain positive number less than P2.
In case BS1200 has confirmed noise characteristic line 405 from the feedback information that receives, BS1200 can calculate the SNR on the WT receiver 1302 for any given transmission power Q so.For instance, in Fig. 4, shown the process that is used for definite and the corresponding SNR of given transmission power Q.At first, BS1200 point (Y1, P2) with (Y1 carries out linear interpolation between P1) so that find out corresponding corresponding received signal power Y421 with through-put power Q:
Through point (X2, P2) with (X1 carries out linear interpolation between P1), can provide the corresponding corresponding noise power with through-put power Q:
Then, through using following formula, can provide that WT1300 experiences and with the corresponding SNR of BS transmitting power Q, i.e. SNR (Q):
On noise characteristic line 405 shown in Figure 4, some A 411 has size and is the Y axis values of Y 421 for the X axis values of X 420 and size, and to put A 411 be corresponding with through-put power Q.Should be noted that for putting the straight line that A 411 links to each other with initial point 422, its slope is SNR (Q), wherein said SNR (Q) is the SNR on WT receiver 1302 when using transmitting power Q.Therefore, for instance, according to the noise characteristic line 405 that from the statistic of WT1300 report, produces, BS1200 can confirm needed through-put power, so that satisfy WT1300 for the needs of specifying SNR.
What Fig. 5 showed is the chart 500 that the relation between the power on the frequency on the transverse axis 503 and the longitudinal axis 501 is described.Fig. 5 is corresponding with an example embodiment of the present invention, and in this embodiment, wireless cellular network has used OFDM modulation (OFDM).Under this exemplary scenario, frequency 505 is divided into 31 orthogonal tones, and so, even there is multipath fading in the channel, the transmission of on different tones, carrying out can phase mutual interference on receiver yet.Minimum signal transmission unit is the single tone in the OFDM code element, and it is corresponding with the combination of time and frequency resource.
What Fig. 5 showed is that tone is in the distribute power of specifying on the OFDM code element.In this embodiment, pilot tone 515 be on certain tone with the known symbols of fixing pilot power 507 emissions, zero 513 of pilot tones are that through-put power is zero tone.These pilot tones 515 and zero pilot tones 513 can be in time and saltus step this means when an OFDM code element changes to next code element, and the shared position of these tones might change.Prolonging in the period, because the hopping sequences repetition, so pilot signal transmission is periodically to carry out.Four pilot tones 515 and one zero pilot tones 513 in Fig. 5, have been shown.Pilot tone 515 all is to know for BS1200 and WT1300 with the tone locations of zero pilot tone 513.In addition, in Fig. 5, also shown 26 data tones 511, they have corresponding transmission power level 509.Of Fig. 5, pilot tones transmission power level 515 is apparently higher than data tones transmission power level 509, and this makes wireless terminal be easy to discern pilot tones.Usually, in all data tones shown in Figure 5, data tones through-put power 509 may not be identical, and its level 509 might change along with the difference of data tones.
As far as the radio configuration situation of disposing with omnidirectional antenna, present embodiment has been stipulated independent zero pilot tone, just usually said sub-district zero pilot tone.As shown in Figure 5, suppose pilot tones with the power P emission, the tone of data services is launched with power Q.So, WT1300 can measure SNR through the pilot signal that observation receives, and here we are called SNR (P) with this SNR.Our purpose is to make base station 1200 can obtain the estimation about SNR (Q), and this SNR (Q) is the SNR that wireless terminal 1300 is assert, it is corresponding with the transfer of data that the base station uses power Q to be carried out, and Q can be different from P.
The information that receives SNR is very important, because said reception SNR will confirm the combination of supported code rate and modulation constellation ideograph.Concerning the target block error rate (the for example probability of the loading error occurring of single code word) and each code rate and modulation constellation ideograph of appointment; Can define a minimum SNR here; Wherein receive SNR and must exceed this minimum SNR, so that the probability of bust this is lower than intended target ratio (for example 1% block error rate).According to this viewpoint, concerning BS1200, it is desirable to comparatively correctly to estimate SNR (Q) that so that solve transmitting power Q, wherein transmitting power Q can be expectation code rate and better SNR of the minimum SNR of ratio of modulation constellation ideograph generation.
Relation between SNR (Q) and the Q depends on the noise of those and signal correction.In order to describe, we suppose and the noise and the transmitting power of signal correction are proportional, and we have also used the noise characteristic line 305,405 that shows in Fig. 3 and 4 to characterize the overall noise correlation as the received signal power function.This principle can expand in other situations equally.
Suppose to represent channel gain that so, when BS carried out firing operation with power P, the received power of wireless terminal will be α P with α.What suppose that N representes is and noise that signal is irrelevant, and γ P representes is and the noise of signal correction that wherein γ is the proportionality factor of transmitting power P.So, in the euphonic SNR of measurement pilot frequency, WT1300 will measure signal to noise ratio:
Wherein P is the constant transmit power of pilot tone, N be WT1300 experience with the irrelevant noise of signal.We represent that through calling this " SNR1 " its can be regarded as an individual entities with the interference of those and signal correction.
Through using zero pilot tone, WT1300 can independent measurement and the irrelevant noise N of signal, and this is because BS1200 transmitting power on this zero tone not.Through the irrelevant noise N of this and signal and the received power α P of BS pilot tone are compared, can estimate the SNR that does not contain signal dependent noise.Here, we suppose that this ratio is:
Wherein title " SNR0 " shows that it does not think not the noise with signal correction.Then, through using following formula, can provide the relation between SNR1 (P) and the SNR0 (P):
For the ease of mark, we define
Through with Fig. 3 and 4 in the noise characteristic line compare, we can find out: what SNR0 (P) was corresponding is the intersection point of straight line and X axle, and SRR1 then is equivalent to the slope of straight line.So, as the function of SNR0 (P) and SRR1, we can write out following formula:
In one embodiment, measurement result SNR0 (P) and SRR1 report to BS1200 by WT1300, and BS1200 can be from calculating SNR1 (P) from these reports.
Chart 600 among Fig. 6 is described is SNR1 (P) and the relation between the SNR0 (P) on the transverse axis 603 on the longitudinal axis 601, and wherein SNR is that unit is drawn with dB.That three curves representing with lines 605,607 and 609 are described respectively is SRR1=0, SRR1=0.5 and SRR1=1.What the situation of SRR1=0 (line 605) was corresponding is noise and the irrelevant situation of signal, so SNR1 (P)=SNR0 (P).What the situation of SRR1=1 (line 609) was corresponding is the situation that signal dependent noise equals signal, so SNR1 (P) will never surpass 0dB.
Then, BS1200 can calculate from the information that receives from WT1300 and receive SNR, and wherein said reception SNR is the function of the transmitting power Q of data service.The SNR that WT1300 receives will comprise the noise with signal correction, and will adopt following form:
Transform and replacement through carrying out, can obtain:
Therefore, as the function of values reported SNR0 of WT1300 institute (P) and SRR1, can be any transmitting power Q prediction SNR that WT1300 experienced here.Of these derivations; Through using zero pilot tone; WT1300 can confirm statistic and it is transmitted into BS1200, so, even there is the noise with signal correction; BS1200 also can predict that to the SNR as the transmitting power function wherein said noise and transmitting power are proportional.
Should be noted that SNR0 (P) and SRR1 institute is different with sending, WT1300 can also launch other report set of equal value to BS1200, and these operations all fall in the scope of the present invention.
Method and apparatus of the present invention is very practical in multi-sector cell.In wireless cellular system, base station 1200 is disposed with a kind of like this structure often, and wherein each has been distinguished into a plurality of sectors shown in Figure 11 for a short time.As far as sectorized environment, sector 1106,1108, the interference meeting between 1110 produce appreciable impact to receiving SNR.Except with the irrelevant part of signal, overall noise has also comprised the part with signal correction, wherein the part of each and signal correction is all with proportional from the signal power of other sectors in the same sub-district 110.Compare with situation shown in Figure 3, in this case, noise characteristic will be more complicated, because under this sectorization situation, overall noise has comprised two or more and component signal correction, rather than one-component.Yet overall noise still can characterize with straight line, and present said straight line defines in higher dimensional space.For example, can use intersection point and slope to describe the noise characteristic line here.Wherein intersection point is the function with the irrelevant noise section of signal, and each slope is corresponding with the proportionality of signal dependent noise part in signal specific power all.
Yet, in some scheme, can simplify description about the noise characteristic line.For example, in exemplary sectorization method, wherein whole transfer resources can be used all or be close in each sector in the sub-district, and frequency band for example is so that carry out firing operation in each sector.Normally fixing or known from the gross power of each sector transmission, but different WT1300 might receive the different piece in the said power.Owing to do not isolate fully between the sector, the signal of therefore in a sector, launching will become the noise (interference) of other sectors.In addition; If each sector 1106,1108,1110 is compelled to specify the degree of freedom to launch identical, proportional or almost proportional signal power, so from other sectors and to be that image signal correlated noise or self noise are such to the interference of the WT1300 in the designated sector 1106,1108,1110 occur.This situation occurs and be because scalable along with signal power, so the line that shows among noise characteristic line and Fig. 3 is very similar from the interference meeting of other sectors.
According to the present invention, BS1200 will launch the signal of " sub-district zero pilot tone " and so on, so that WT1300 can combine all and the irrelevant noise of signal to come the intersection point of estimating noise characteristic curve.In addition, for instance,, can make the WT1300 that is in sector borders 1150,1152,1154 not receive interference (or reducing the interference that is suffered) from other sectors through sector 1106,1108, scheduling between 1110 are coordinated.According to the present invention, BS1200 will launch the signal of " sectors zero pilot tone " and so on so that WT1300 can be under only taking into account from the situation of the signal dependent noise of sector subset the slope of estimating noise characteristic curve.Then, according to the present invention, WT1300 SNR that those and signal is irrelevant and different slope or equivalent information on reverse link are gathered and are reported to BS1200.
Fig. 7 has shown the signaling that is used for the embodiment of the invention in diagram 700, wherein said embodiment is in such a case, and that promptly the cellular wireless system of sectorization uses is orthogonal frequency division modulated (OFDM).Imagine a BS1200, wherein in all sectors 701,703,705, all reused identical carrier frequency with three sectors 701,703,705.Represent with reference number 709,713 and 717 respectively with sector 701,703,705 corresponding pilot power level.Each sector in first to the 3rd sector, its data-signal power level is represented with reference number 711,715,719 respectively.To discuss the situation of sector hereinafter with other quantity.Suppose three sectors the 1106,1008, the 1110th of base station 1200 here, represent with S0 shown in Figure 7 701, S1 703 and S2 705.What Fig. 7 showed is the tone assignment of on the OFDM code element 707 of three sectors and appointment, implementing for downlink transmission; The instance that has wherein comprised the data tones position; For example exemplary data tones 728, and comprised the instance of pilot tone position, for example exemplary pilot tones 728; The instance that has comprised zero pilot tone position in addition, for example exemplary zero pilot tones 721.Suppose that here each sector shares same frequency band, therefore, the corresponding tone between the sector will the phase mutual interference.Should be noted that, here only be position and the order that has shown tone for purpose of explanation, and in different embodiment, tone locations can change with order.
According to the present invention, down link signal has comprised one or more sub-districts zero pilot tone, and these sub-districts zero pilot tone is the zero tone that each sector 701,703,705 is shared.In zero pilot tone 729 of sub-district, the through-put power of each sector 701,703,705 all is zero.In addition, down link signal has comprised one or more sectors zero pilot tones 721,723,725, and wherein only in the subclass of sector 701,703,705, through-put power is only zero.In the tone identical with the sectors zero pilot tone, comparatively it is desirable to have a pilot tones or data tones, the through-put power of wherein said tone is fixed, and is that WT1300 in another sector is known.For example, the sectors zero pilot tone 723 among the sector S1 703 has corresponding with it pilot tones 731 in sector S0 701, and in sector S2 705, has corresponding with it pilot tones 737.
In the embodiment that Fig. 7 shows, four pilot tones, a sectors zero pilot tone and sub-district zero pilot tone are arranged all in each sector 701,703,705.For example, sector S0 701 has 731,733,735,737 and sectors zero pilot tones 721 of four pilot tones and sub-district zero pilot tone 729.Through these pilot tones are arranged, can make each sector all have two unique pilot tones, then with two other sector in each sector share a pilot tone.For example, sector S0 701 has unique pilot tone 735,727; And pilot tone 731 is shared a pitch frequency with the pilot tone 737 of sector S2 705; And pilot tone 733 is shared a pitch frequency with the pilot tone 739 of sector S1 703.In addition, the sectors zero pilot tone of a sector is consistent with pilot tones in other sectors.For example, as far as the zero tone 725 among the sector S2 705, pilot tone 733,739 is respectively to launch on the tone identical in sector S0 701 and S1 703.In addition, the position of pilot tones, sub-district zero tone and sectors zero tone is all known for BS1200 and WT1300.
Owing to many reasons such as frequency diversities, pilot tone can change its position or in time and " saltus step ".Fig. 8 has provided an instance of the tone saltus step of pilot tone, sub-district zero pilot tone and sectors zero pilot tone.What the chart 800 among Fig. 8 was described is frequency and the relation between the time on the transverse axis 803 on the longitudinal axis 801.Wherein each little longitudinal divisions 805 is all corresponding with a tone, and each little transversal sectional 807 is all corresponding with an OFDM symbol time.Each pilot tones 809 all is with the little box indicating with vertical shading.And each sectors zero pilot tone 811 is with the little box indicating with horizontal shading line.Each sub-district zero pilot tone 813 then is with the little box indicating with cross-hatched.
In one embodiment, pilot tones is actually according to modular linear saltus step figure and comes saltus step.According to the present invention, the sectors zero tone is to according to identical modularization linear figure generation saltus step with the pilot tone saltus step of same slope value.In addition, in one embodiment of the invention, the pilot tone saltus step of sub-district zero pilot tones and same slope value is according to equal modules linear figure generation saltus step.
In one embodiment, the data tones linear saltus step figure of modularization that comes down to change according to sequence comes saltus step.In another embodiment of the present invention, sub-district zero pilot tone saltus step and data saltus step are to come saltus step according to the equal modules linear figure that sequence changes.In this embodiment; When sub-district zero pilot tones and certain pilot tones clash; Wherein all can stop the transmission of pilot tones in each sector, and said pilot tones will be removed efficiently, but at least in some sector; The transmission of pilot tones will continue, and in fact sub-district zero pilot tones will become unavailable.
Suppose that the sector S0 in WT1300 and the base station 1200 connects, and the channel gain from S0 to WT1300 is provided by α.Equally, suppose that the channel gain from S1 to WT1300 is provided by β, and the channel gain from S2 to WT1300 is provided by γ.At last, for the sake of completeness, suppose in the link from S0 to WT1300 that comprise self noise with the noise of signal correction, wherein said self noise and channel gain are that the transmitting power of δ is proportional.
Suppose that the transmitting power of data tones is provided by Q0, Q1 and Q2 respectively in these three sectors.As far as the link from S0 to WT, receive SNR and provide so by following formula:
At the remainder of this argumentation, suppose that the interference (β Q1 and γ Q2) that other sectors cause is far longer than the interference from the signal dependent noise δ Q0 in the same sector, so, for simplicity, will omit this in follow-up argumentation.
WT1300 should provide one group of parameter to the base station, and the base station will have enough information and comes to receive SNR for the prediction of 1300 downlink transmission from S0 to WT thus.In order to obtain this information, zero pilot tones can be used in the base station.In zero pilot tone of sub-district, the transmission of each sector all is zero, through using said sub-district zero pilot tone, can measure and the irrelevant noise of signal.In addition, compare, can provide following SNR through receiving intensity with itself and S0 pilot tone:
Next, in various embodiment, if one of them adjacent sectors is not carried out firing operation, the sectors zero pilot tones can be used to measure SNR so.Especially, be the corresponding pilot tones of sectors zero pilot tones among sector S0 imagination and the S2 here.Then,, can measure, can obtain following numerical value thus SNR according to this pilot tone among the S0 of sector:
Wherein interference sector is S1 (having path gain β).Equally, through to measuring as the SNR on the pilot tones of the sectors zero tone among the S1, interference sector will be sector S2 (having path gain γ), and the SNR that finally obtains is provided by following formula:
In both of these case, the slope of noise characteristic line is respectively
Next, if SNR be with not with other sectors in the corresponding pilot tones of sectors zero pilot tone directly measure, this SNR measuring operation will be taken the interference from other two sectors into account so.Because this measurement result has comprised the interference from two sectors, therefore be referred to as SNR2 here.
In this case, the slope of noise characteristic line is
Through following SRR being defined as the appropriate slope value of noise characteristic line, can be with SNR1
γ(P) and SNR2 (P) and SNR0 (P) link together:
SRR itself can represent and calculating as follows with SNR:
Should be noted that SRR2 can be used as SRR1
Then can SNR be written as the form of SNR0 (P) and SRR then:
If WT1300 is with one of these statistics abundant collection (for example SNR0 (P), SRR1
γ, SRR2) report to base station 1200, the SNR that WT1300 receives can be predicted according to transmitting power Q0, Q1 and Q2 in base station 1200 so.That summarizes says, as far as having power Q0, have from the interference of sector S1 and S2 and the transfer of data with power Q1 and Q2, the SNR that WT1300 experienced is through being that the pilot tones of P is carried out to measure and is presented to transmitting power:
In Fig. 9, three kinds of situations that diagram 900 has shown about the exemplary WT among the S0 of sector.Sub-district 901 comprises three sector S0 903, S1 905 and S2 907.Fig. 9 has shown a WT909 near the border of sector S1 905, and wherein WT 909 receives the serious dl interference from sector S1 905.Sub-district 921 has comprised three sector S0 923, S1 929 and S2 927, and this sub-district 921 has shown a center that is in sector S0 923, and away from the WT929 of sector borders.Sub-district 941 has then comprised three sector S0943, S1 945 and S2 947, and that it shows is the WT949 near the border of sector S2 941, and wherein WT949 has received and come the serious dl interference since sector S2 947.
In one embodiment of the invention, in each situation in these three kinds of situation, WT can send a sub-set of tested statistic to BS1200, so that reduce the amount of information of transmitting on the reverse link, wherein said reverse link can be a up link.
As far as the situation that reference cell among Fig. 9 901 is shown, suppose that the WT909 among the sector S0 903 has received the serious interference from sector S1 905.So, the transmission that the coordinated scheduling device 1225 that is used for the base station can cut off sector S1 905 and sector S0 903 to WT909 is the transfer of data of mutual interference mutually.Simultaneously, through coordinating the transmission among the sector S2 907, can make it to have transmitting power Q identical with its transmitting power that in the S0 of sector, is had or much at one.Then, through using following formula, can provide the SNR that WT909 experiences:
In this case, as long as report SNR0 (P) and SNR1
γCan satisfy the demand.
Next, the situation that reference cell 921 is shown in Fig. 9, wherein WT929 can carry out firing operation thus, and can not cause too many interference to WT929 not near sector borders on great majority or all sectors.In this case, suppose that base station dispatcher 1225 made the simplification hypothesis that each sector in three sectors all should be launched data with equal-wattage Q.So, as far as transmission,, can provide the SNR that WT929 experiences through using following formula from sector S0 923:
In this case, as long as report SNR0 (P) and SRR2 can satisfy the demand.
Next, the situation that reference cell 941 is shown in Fig. 9, WT949 is positioned near the sector borders of having a common boundary with sector S2 947.Because WT949 has received the serious interference from sector S2 947, so the coordinated scheduling device 1225 of base station 1200 can cut off the respective data transfer among the sector S2 947.Simultaneously, suppose that the transmission of sector S1 945 and transmission among the sector S0 943 are with identical transmitting power Q scheduling.So, through using following formula, can provide the SNR that WT949 experiences:
In this case, as long as report SNR0 (P) and SRR1
βCan satisfy the demand.
Therefore, if the BS1200 limit transmit power makes it to equal certain value Q or equals 0, all only need an information subset be transmitted into BS1200 from WT1300 in each structure in these three kinds possibility structures so.Especially, in one embodiment, wireless terminal 1300 is confirmed WT1300 present located situations (for example sub-district 921 among the sub-district among Fig. 9 901, Fig. 9 and the sub-district 941 among Fig. 9 are shown situation).WT1300 can be with this information as the sector borders designator of dibit and it is transmitted into BS1200.What the sector borders designator was indicated is the positional information of wireless terminal with respect to sector borders.Wherein first bit representes whether WT1300 is in the border and whether is necessary to cut off the transmission in the adjacent sectors thus.Second bit can represent that which sector in these two sectors produces more large disturbance.
In the table 1 of being set forth hereinafter, the 1st what enumerate is 2 possible bit sector borders designators.Secondary series in the table 1 is then represented noise contribution information.The 3rd what enumerate is BS1200 to receiving the respective sectors boundary indicator and responding and the control operation of taking.The 4th what enumerate is two channel quality indicated values under the situation that has provided the corresponding report sector borders designator that same ranks lift, reporting.
|The sector borders designator || SNR ||Other sectors ||The WT report |
| 00 || SNR
||Carry out firing operation in all sectors || SNR0(P)，SRR2 |
| 10 || SNR
||Cut off sector S2 || SNR0(P)，SNR1
| 11 || SNR
||Cut off sector S1 || SNR0(P)，SRR1
So, because WT1300 identified first-selected structure to base station 1200, so WT1300 only need report one among SNR0 (P) and three SRR.
To discuss multi-sector cell now with any amount sector.In another embodiment of the present invention, if for the situation of the sector that has any amount, can the sector be divided into three kinds of sectors type so, wherein we come these sectors type of mark with S0, S1 and S2.This sectors type classification is accomplished as follows, and wherein two adjacent sectors can not have identical type.Concerning two non-conterminous sectors, suppose that the influence of disturbing is considered to enough little and can produce significant impact, the main cause of interference comes from dissimilar adjacent sectors so.So then can use with the similar mode of three sector cells to come this situation is handled, because in each sector, the main source of interference is all from two sectors adjacent with this sector.
What Figure 10 comprised is diagram 1000, and what this diagram showed is to have the exemplary cells 1001,1021 of 3,4,5 sectors and 1041 sectors type respectively.Sub-district 1001 has comprised the sector 1003 of the first sector S0 type, the sector 1005 of the first sector S1 type and the sector 1007 of the first sector S2 type.Sub-district 1021 has comprised the sector 1023 of the first sector S0 type, the sector 1025 of the first sector S1 type, the sector 1027 of the first sector S2 type and the sector 1029 of the 2nd S2 type.Sub-district 1041 has then comprised the sector 1043 of the first sector S0 type, the sector 1045 of the first sector S1 type, the sector 1047 of the first sector S2 type, the sector 1049 of the 2nd S0 type and the sector 1051 of the 2nd S1 type.Table 2 hereinafter described provides a scheme case for the sector of varying number, and wherein the order of sectors type tabulation is corresponding is its order (for example clockwise direction) that centers on the sector and advance.
|Number of sectors ||Sectors type |
| 1 ||S0 |
| 2 ||S0，S1 |
| 3 ||S0，S1，S2 |
| 4 ||S0，S1，S2，S1 |
| 5 ||S0，S1，S2，S0，S1 |
| 6 ||S0，S1，S2，S0，S1，S2 |
| 7 ||S0，S1，S2，S0，S1，S2，S1 |
| 8 ||S0，S1，S2，S0，S1，S2，S0，S1 |
| 9 ||S0，S1，S2，S0，S1，S2，S0，S1，S2 |
Through using above-mentioned sectors type scheme, can the scheme that be used for three sector examples and comprised sub-district zero pilot tone and sectors zero pilot tone be used for the sector of any amount.
Though in the ofdm system environment, method and apparatus of the present invention is described, method and apparatus of the present invention also is applicable to various types of communication systems, comprising the system of numerous non-OFDM types.In addition, some characteristic also is applicable to non-cellular system.
In various embodiment, described here node is realized with one or more modules, carries out and the corresponding step of one or more methods of the present invention thus, and for example signal processing, message produce and/or transmitting step.Therefore, in certain embodiments, different characteristic of the present invention realizes with module.These modules can realize through using software, hardware or the combination of software and hardware.In said method or method step; There are a lot of methods or method step to implement with the machine-executable instruction that comprises in the machine readable media; Can control the equipment that is with or without additional firmware of all-purpose computer and so on thus, so that in one or more nodes, realize the part in whole said methods or the said method, wherein for instance; Said machine-executable instruction can be a software, and said machine readable media can be memory devices such as RAM, floppy disk.Correspondingly, the invention still further relates to a kind of machine readable media that comprises machine readable instructions, said instruction impels equipment of processor and so on and related hardware to carry out the one or more steps in above-mentioned one or more method.
According in the preceding text about description of the invention, those skilled in the art can know the numerous additional variation of understanding the foregoing invention method and apparatus.These variations all are regarded as and fall in the scope of the present invention.In different embodiments of the invention, method and apparatus of the present invention can with CDMA, OFDM (OFDM) and/or other those can be used for providing the communication technology of wireless communication link to be used in combination between access node and the mobile node.In certain embodiments, access node realizes that as the base station wherein said base station has used OFDM and/or CDMA to set up communication link with mobile node.And in various embodiment, mobile node be as notebook, personal digital assistant (PDA) or other those comprised receiver/transmitter circuitry and be used for the logical circuit of embodiment of the present invention method and/or the portable equipment of program is realized.
What Figure 14 described is the step of in a plurality of sectors of sub-district, launching the exemplary method 1400 of pilot tones according to the present invention and with the method for synchronization.This method starts from start node 1402 and proceeds to step 1404, in this step, will carry out initialization to current symbol time counter, for example it is initialized as 1.In example system; Code element is to send with the mode of code element one by one; Symbol time then be code element of emission and one-period property prefix the time that will use; The copy of the part of the code element that wherein said periodicity prefix is normally launched, it is added in order to provide redundant, can prevent that thus multipath from disturbing and small code element transmit timing error.
Then; Operation will proceed to step 1406 from step 1404; And in step 1406, will control transmitter; So that the preliminary election transmission power level of each sector in the use sub-district and in each sector, launch those with the same tone and the method for synchronization according to the pilot transmission sequence of preliminary election and be about to pilot transmitted code element in current symbol time and each sector, wherein said preliminary election pilot transmission sequence can be the pilot tones hopping sequences.Though be the parallel pilot tone of launching in each sector of sub-district, concerning zero tone, the emitted power level might be some preliminary election level or zero on certain tone.Though the pilot signal transmission time is synchronous in each sector usually, between the sector, slight timing slip might occur.What therefore, in fact used each sector is different code element transmission time periods.Yet the symbol time in each sector has all carried out fully synchronously, and in each sector, is used for existing sizable overlapping at the symbol time of each sector transmission code element.Usually, a large amount of overlapping meetings are synchronized to the code element transmission time started and launch in periodicity prefix corresponding at least one period of launch time, wherein should be also referred to as the periodically prefix duration time sometimes.Therefore, in general,, between the symbol time of different sectors, also still exist overlapping in a large number even symbol time is overlapping not at all.
In the special code elementary time; The judgement that which tone is used for pilot tones is to make according to the tone information 1238 that pilot tone hopping sequences tone information 1234 comprises; And in each sector of sub-district, the power that uses on the designated tones is confirmed from power level information 1236.
In step 1406, in case launched pilot tones at current symbol time, operation will proceed to step 1408 so, and in step 1408, the time counting of current code element will add 1.Then, in step 1410, will carry out inspection, whether reach the maximum symbol time so that understand current symbol time.If current symbol time equals its maximum, so current symbol time will reset to 1, in step 1406, begins repetition pilot tone hopping sequences thus.The cyclical transmission of pilot tones will according to the pilot tones hopping sequences implemented and continue repetition, stops or till other incidents impel the pilot signal transmission process to interrupt up to base station transmits.
With reference now to Figure 15～17,, various exemplary pilot tone transmission and pilot signal transmission power information have wherein been shown.
According to the present invention, in a plurality of sectors of sub-district, pilot tones is launched with same tone simultaneously or almost simultaneously.In different embodiments of the invention, the code element transmission time can obtain in the different sectors of sub-district synchronously.If fully synchronously, so in any fixed time, will be fully overlapping in time between the pilot transmitted tone in the different sectors of sub-district.Unfortunately, as stated,, therefore may not realize accurately synchronously because very complicated synchronously and other many reasons are carried out in different amplifiers and the transmission between the antenna at high-frequency work.But in the synchronized sectors execution mode, between the sector, exist a large amount of symbol times overlapping.Can realize pilot transmission thus, overlappingly will produce signal measurement wherein in a large number, and said signal measurement hypothesis is as far as each sector code element transmission time, a part of at least therein sector code element possibly occur overlapping fully in the transmission time.As stated, in synchronization implementation example of the present invention, the difference of the code element transmission start time in the sub-district between the different sectors often is less than the duration of those periodicity prefixs that are included in transmit symbol usually.
From discussing purpose, here suppose to exist fully synchronously, wherein this type of code element signal is that launch with the method for synchronization each sector in multi-sector cell simultaneously.Yet the argumentation in the preceding text shows that this precise synchronization can not occur usually and is not that embodiment of the present invention is necessary.Therefore, all corresponding different symbol time of the transmission in each sector, this symbol time can depart from the symbol time of adjacent sectors slightly.According to the present invention; When each sector in the sub-district is launched pilot tones with the method for synchronization on same set of tones; The pilot tones power of different sectors will be controlled in the sub-district; So that the permission various signals is measured, in particular sector, these measurements will help to confirm from other sectors, the for example noise contribution and the background noise of one or more adjacent sectors.
Measure in order to help to carry out multiple various signals, can use a plurality of pilot tones in the transmission time in single code element.As selection, each symbol time also can only use a pilot signal, wherein at different symbol times, for example will be allocation of pilots different power level in the continuation code elementary time.In this case, according to the present invention, the pilot signal measurement of carrying out at different symbol times can be used to produce two different channel quality indicated values, and these two indicated values will return to the base station.
Figure 15 is the chart 1500 that is presented at the biparting district pilot tones transfer sequence of implementing in the example embodiment of the present invention.As mentioned below, sequence shown in Figure 15 can expand in the system with N sector, and wherein N is the Any Digit greater than 1.The sequence that Figure 15 shows is to aim at a sub-district that has comprised two sectors to implement, and these two sectors are respectively sector A and sector B.Symbol time in each sector can offset somewhat; But said symbol time is overlapping basically; Therefore, though these two symbol times all are different slightly symbol times under many circumstances, here be that it is described as identical symbol time.The title of first row 1502 is the time, and it refers to the symbol time of emission tone under situation synchronous fully between the hypothesis sector.In one embodiment, if be that pilot signal has been used identical tone at each symbol time, each symbol time 1～4 is all corresponding with different current symbol times so.The title of secondary series 1504 is tones, and what it was enumerated is the tone in order to the emission pilot signal, for example frequency.In these row, each provisional capital is corresponding with a tone.According to specific implementations, different row can corresponding identical or different tone.For instance, if first to the 4th symbol time is identical current symbol time, so, because each pilot signal all needs a tone, therefore, first to the 4th tone of in row 1504, enumerating will be different.Yet if the correspondence of first to the 4th symbol time in the row 1502 is different current symbol times, the tone of enumerating in the row 1504 so can be identical, also can be different.
As stated, each row 1512,1514,1516 is all corresponding with the tone transmission of the sector A of sub-district and each sector among the B with 1518, and wherein said tone can be the tone that is used to launch pilot signal.In each sector, transmission power level can be identical, also can be different.And in all cases, put the pilot transmitted tone at any time all with previously selected through-put power emission.So; Owing to will be kept in base station 1200 and the wireless terminal 1300 in order to the through-put power and the tone of emission pilot signal; Therefore these two equipment all can be known said information, and these two equipment all are to understand current symbol time in the valid timing information from the sub-district.In Figure 15, what the 3rd row 1506 were enumerated is the pilot signal transmission power level of pilot transmitted signal in the A of sector, and what wherein said transmission was used is and the corresponding tone of specific row.Equally, what the 4th row 1508 were enumerated is the pilot signal transmission power level of pilot transmitted signal in the B of sector, and said transmission use is and the corresponding tone of specific row equally.In order after a while three sector embodiment being described, to have comprised each row 1502～1510 here, but then be not to have used these each row wherein in described biparting district execution mode with reference to Figure 15.
What each rectangle in the row 1506 and 1508 was represented is the step of in indicated sector, using the regular code elementary time emission pilot signal of the tone of expression in the row 1504 and expression in row 1502.In practice, in each sector A and B, tone all is in the emission of different slightly symbol time, for example with row 1502 in the basic first and second corresponding symbol times of symbol time enumerated.Wherein 1 be used to the non-zero pilot tone of indicating to have the first preliminary election through-put power, 0 is used to indicate one zero tone transmission, for example is the pilot signal of zero power emission with the size.
Shown in row 1512, in the A of sector, using tone 1 and having launched numerical value at symbol time 1 is 1 pilot signal, but what in the B of sector, launch is zero pilot signal.So, in the B of sector, can measure the influence of the inter-sector interference that causes on the transmission same tone within it of sector A.Allow sector A under the situation of the interference that transmission caused that does not have sector B, accurately to measure the decay among the A of sector in addition.What row 1514 was corresponding is symbol time 2, and in this symbol time, tone 2 will be used to emission zero tone in the A of sector, and will to be used in the B of sector emission numerical value be 1 pilot signal.Allow sector A to confirm the signal interference volume that being transmitted among the B of sector caused on the same tone thus.What row 1516 was corresponding is symbol time 3, in this symbol time, used tone 3 and in two sector A and B the zero pilot signal of emission, can measure the conventional background noise on the tone 3 thus.What row 1518 was corresponding is symbol time 4, and in this symbol time, it is 1 pilot signal that sector A and B have used tone 4 to launch numerical value.In this case, the effect that in each sector A and B, transmits with identical non-zero power level can be measured simultaneously in each sector.Usually; Pilot signal is to launch according to first and second row 1512,1514 among Figure 15 and the delegation at least in row 1516 and 1518; Allow wireless terminal to carry out enough signal measurements thus; This signal measurement will and be that these two function institutes are essential as two different function inputs, and wherein said function is used for producing first and second channel quality indicated values according to a characteristic of the present invention, and this indicated value is the feedback that turns back to base station 1200.
What Figure 16 described is the exemplary pilot tone transfer sequence that is used for three sector systems.The same with the instance among Figure 15; What first row 1602 were corresponding is the code element transmission time; What secondary series 1604 was corresponding is tone, row 1606,1608 and 1610 then respectively expression be the pilot signal transmission in each sector among three sector A having in the sub-district, B, the C.Therefore; The same with the instance among Figure 15, with each rectangle in first the corresponding row 1606,1608 of certain delegation and 1610 in the fifth line 1612,1614,1616,1618,1620 represent be in indicated sector on indicated tone the step of emission pilot signal.As stated, though the employed tone of each row all is identical in each sector, at each symbol time during all corresponding to same current symbol time, first each tone in transferring to the five notes of traditional Chinese music will be different.Yet when each symbol time in first to the 5th symbol time was all inequality, first to transfer to the five notes of traditional Chinese music can be identical, also can be different.
Should be noted that at least one such pilot signal that in the execution mode of Figure 16, has been each sector transmission wherein will be used to launch emission zero pilot tone on the tone of said pilot signal in the adjacent sectors of said sector.It is noted that be expert at and used the content that is described as zero sub-district in 1620, wherein said content helps to carry out hum measurement.
Figure 17 is the chart 1700 that shows with the similar three sector execution modes of Figure 16, and wherein pilot transmitted is according to power level and with more general formal description in each sector.15 pilot tone P1～P15 have been transmitted in the execution mode demonstration of Figure 17, if each row correspondence is the different transmitted symbol cycles, each pilot tone is to launch at different symbol times so.If each cited signal all is to launch at identical symbol time; Will show three different symbol times so here; Wherein the transmission time of each sector different slightly, but the symbol time that uses in basic corresponding symbol time of said transmission time and other sectors is identical.
The same with the instance of Figure 15 and 16, the pilot tone in each row 1712,1714,1716,1718,1720 is all with the same tone emission, but different row can be corresponding to different tones.Though as cited in first row 1702; What here show is to transmit at 5 different symbol times; But taking the sectored transmissions time into account when changing, each rectangle of on the title sector, enumerating actual corresponding be different symbol times, wherein symbol time of each row is overlapping basically; And under the situation of precise synchronization, said symbol time equates.In the first to the 15 pilot tone P1～P15, the power level of each pilot tone representes in bracket that all for example, the through-put power of P1 is p1.Though some supports two different power level in the situation of instance shown in figure 16, a plurality of known power levels equally also can be supported.Last column 1720 expressions among Figure 17: in all cases, the zero pilot signal transmission that in each sector A, B and C, accordings to these pilot signal power level and use tone 5 to be carried out is zero.
What chart 1750 shown in Figure 180 was described is the signal transmission of on 10 different tones, being carried out in the transmission period in single code element.In the execution mode of Figure 18,0 is used to represent zero pilot signal, and 1 is used to represent to be in the pilot tone of known non-zero transmission power level, and wherein said transmission power level is usually greater than the power level in order to the emission data.In chart 1750, used D to describe the performed transfer of data in certain sector among sector A, B and the C.Data-signal D normally on certain tone with the power level that is lower than pilot signal level 1, therefore said signal can seriously not disturb the pilot tone in the adjacent sectors.In each sector, data are normally launched on the additional tones that described symbol time does not show in Figure 18.In OFDM embodiment of the present invention, in designated sector, because the additional data tone is a quadrature with the tone of launching pilot signal, therefore this additional data tone can not disturb pilot tones.Figure 19 describes is to come method 1800 that 1200 pilot signals that receive from the base station are handled through the operate wireless terminal, wherein said pilot signal according to the present invention quilt launched.The pilot signal that receives can be to use known different transmission power level pilot transmitted signals; Allow receiving equipment to carry out various signal measurement and the calculating that are used for confirming different noise contributions thus; Wherein for instance, said noise contribution can be background noise and inter-sector interference.
Method 1800 starts from start node 1802, and handles the path along two that with step 1804 and 1808 are the beginning respectively and carry out.For instance; If have a plurality of pilot signals of different transmission power levels in single symbol time emission; These two processing paths can be implemented with parallel mode so; If the different code element transmission times uses same tone but the different capacity level is launched pilot tone in order, these two processing paths can be implemented with serial mode so.
In step 1804, measure at least one in the amplitude of 1300 pairs first pilot signals of wireless terminal and the phase place, so that produce the first measured signal value, wherein said first pilot signal is launched with through-put power P1.Then, in step 1806, will use the first measured signal value.In step 1806, first channel quality indicated value produces from the first measured signal value according to first function f 1, and wherein said first function uses the said first measured signal value as input at least.For instance, first channel quality indicated value of function f 1 generation can be SNR value or the signal power value corresponding to the said first reception pilot signal.When producing first channel quality indicated value, except the first measured signal value, function f 1 can also use other signal measurements result and/or other information as input.And operation will proceed to step 1812 from step 1806.
In certain embodiments; Step 1808 can with step 1804 executed in parallel; And in said step 1808, wireless terminal 1300 will be measured the amplitude of second pilot signal and at least one item in the phase place, and wherein said second pilot signal is to launch with the through-put power P2 that is different from P1.Said measurement will produce the second measured signal value, then, in step 1810, will use this value.In step 1810, the second channel quality indicated value produces from the second measured signal value according to second function f 2, and wherein said second function f 2 has used the second measured signal value as input.Second function is different from said first function, and it has used the second measured signal value as input at least, but also can use other signal measurements result as input.In certain embodiments, the second channel quality indicated value that second function produces is and the corresponding SNR value of second pilot signal, but in other embodiments, it is one and the corresponding signal power value of second pilot signal, for example received signal power designator.And the operation meeting proceeds to step 1812 from step 1810.
In step 1812, wireless terminal 1300 is confirmed the position of wireless terminal with respect to one or more sector borders from above-mentioned measured signal value and/or other boundary position indicated value information.In step 1814; Through using other information that produce in retive boundary position and/or the step 1812; Wireless terminal 1300 will produce a boundary position indicated value 1814, wherein for instance, said indicated value have with table 2 in row 1 shown certain be worth corresponding value.Under having obtained from step 1806 and 1810 first and second channel quality value and the situation from the boundary position indicated value of step 1814, operation will proceed to step of transmitting 1816, and in this step, the information that is produced will be sent back to base station 1200.
Step 1816 comprises to be transmitted first and second channel quality indicated values and boundary position indicated value as the part of one or more message.Show two selectable process paths here, wherein in any specific implementations, all only used an independent processing path.The first processing path starts from substep 1820 and ends at step 1826, and what its was represented is the situation that in single message, has comprised different information.The second processing path starts from step 1830 and ends at step 1840, and its corresponding different message that is to use is launched the situation of each different value.In this environment, will explain synoptically message, and these message comprised be used to transmit the signal of the particular value that will transmit.
Will merge to first message to first channel quality indicated value in step 1820.Then, in step 1822, will merge to first message to the second channel quality indicated value.Next, in step 1824, can the boundary position indicated value be merged to first message.Then, in step 1816, said first message is delivered to base station 1200 through emission first message on wireless communication link.In various embodiment, this processing is to use from wireless terminal to accomplish to one or more dedicated time slots of the control channel of base station 1200 reporting channel qualities and/or other feedback informations.Because used the wireless terminal dedicated time slot to come reporting channel quality and other information, therefore, other wireless terminals or equipment in the sector can not use this time slot.So, through using the dedicated time slot transmission, can avoid clashing.In addition, transmit specific control information, can produce these values so and in these time slots, transmit these values, and needn't send header or other information of the implication that is used to indicate the value of being launched if this channel is specifically designed to.In other words; Base station 1200 will know that the value of on used control channel, launching has certain preliminary election form, in addition, and for instance; What said value representation was also known in the base station is first and second channel quality indicated values, and what follow thereafter is the boundary position indicated value of dibit.So then can the amount of overhead that this type of header overhead is used to launch said message and/or numerical value be reduced to minimum.In step 1826, if finish the value that transmission is generated, operation will turn back to step 1804 and 1808 so, wherein will carry out signal measurement to new pilot signal, and feedback processing also can continue to repeat in time.
What step 1830 was corresponding is the optional value transmission path that shows in the step 1816; In step 1830; First channel quality indicated value will merge in first message, and wherein said first message can be signal, and said subsequently first message can be sent to the base station in step 1832.Then, in step 1834, the second channel quality indicated value will merge in second message, and wherein said second message also can be signal, and said second message transmits in step 1836.In step 1838, the boundary position indicated value will merge in the 3rd message, and then, this message can be sent to base station 1200 in step 1840.The situation that merges message is the same with in step 1826, transmitting, and the special-purpose segmentation that the single message of emission can be specifically designed to through use in the control channel that transmits feedback message in step 1832,1836 and 1840 transmits.Operation will proceed to step 1804 and 1808 from step 1840, and is used to produce channel feedback information and then can repeats in time to the processing of base station 1200 report informations.
Flow chart description shown in Figure 20 be a kind ofly to operate the method for base station (BS) 1200 according to the present invention, wherein for instance, said method is used to launch pilot tones and reception and handles feedback information, confirms the power level in order to transmitted data signal thus.This method starts from step 1902, and wherein base station 1200 will power up and come into operation.In step 1904; The base station transmitter 1204 that is coupled with multi-sector antenna 1205 simultaneously with the method for synchronization and use the predetermined electric power level and tone and with pilot signal transmission to multi-sector cell each sector in 1104 for example; For example S0 1106, S1 1108, S2 1110; So; In the process that pilot tones is transmitted into each sector 1106,1108,1110 in the sub-district 1104, used identical set of tones, and in each sector 1106,1108,1110, these pilot tones were launched in the essentially identical time.Pilot tones transmission in the step 1904 is through using pilot tones power level information 1236 and tone information 1238 and under the guide of pilot signal generation and transmission control procedure 1230, carrying out.Then; Operation will proceed to step 1906, and wherein BS 1200 can receive message from least one wireless terminal (WT) 1300, and these message have comprised one group of channel quality indicated value; For example first and second channel quality indicated values, and sector borders positional information.Said message is to receive under the guide of the reception signal handler 1260 that in base station 1200, comprises.In step 1908, under the guide of channel quality indicated value extraction module 1262, at least two different channel quality indicated values 1250 are extracted in the base station from the single message that comes from wireless terminal 1300 or a plurality of message.In certain embodiments, each channel quality indicated value all is in the separate message.But in other embodiments, in single message, will comprise a plurality of channel quality indicated values from WT1300.Then, in step 1910, under the control of position information extraction modules 1264, the positional information of the position that is used to indicate wireless terminal 1300 relative multi-sector cell borders, for example boundary position indicated value are extracted in base station 1200 from receive message.This positional information can be transmitted in separate message by WT1300, also can be included in certain message that contains channel quality indicated value.Whether this positional information can discern WT1300 near sector borders; And which sector borders can discern approaching is; Wherein for instance, this positional information can be discerned which adjacent sectors to receive the sector that has with disturbing relevant more large transmission power level from.At BS1200, the sector borders information of from receive message, extracting will be kept in the sector borders positional information 1252.
Operation proceeds to step 1912; Under the guide of transmit power calculation program 1226; Base station 1200 is calculated from first and second channel quality indicated values 1250 at wireless terminal 1300 at least and is realized the needed amount of transmit power of expection signal to noise ratio, and wherein said first and second channel quality indicated values 1250 receive from wireless terminal 1300.In step 1914, base station dispatcher module 1225 judges for wireless terminal 1300 produces scheduling through operation.At substep 1916; Base station dispatcher 1225 comes to make a determination for WT1300 according to determined SNR; For instance; BS1200 can be the segmentation on the WT1300 scheduling channel, and the I that the transmission power level of wherein said segmentation can make the reception SNR of WT1300 exceed used data rate and encoding scheme is accepted level.At substep 1918; The scheduler 1225 of BS1200 comes to make a determination for WT1300 according to sector borders positional information 1252; For instance, one is confirmed as near the WT1300 of sector borders, base station 1200 can be its assignment channel segment; Wherein in adjacent sectors, do not have through-put power with the corresponding segmentation of said channel segmentation.Proceed to step 1920; Under the guide of signaling procedure 1228; The transmitter 1205 of BS1200 can use the through-put power of from said at least two channel quality indicated values 1250 that receive, confirming to transmit to said WT1300 at the fixed time, and wherein said signal can comprise the user data 1244 by encoder 1214 codings.
Then, operation will turn back to step 1904 from step 1920, and said method will repeat.In step 1904, base station 1200 will regularly be transmitted into each sector in the multi-sector cell with the method for synchronization with pilot signal repeatedly.Yet; Different wireless terminals 1300 can comprise the message of the set of channel quality indicated value 1250 and sector borders positional information 1252 at different time and/or with the different rates emission; Wherein said time and/or speed depend on the factor such as the wireless terminal operating state; For example open maintenance, dormancy.
In addition; The invention still further relates to machine readable media; Wherein said medium has comprised machine-executable instruction, can control processor or other equipment thus, so that carry out processing according to one or more distinct methods of the present invention; Wherein said medium can be memory, CD or the like, and machine-executable instruction can be software module or order.The different characteristic of method and apparatus of the present invention can be used in various communication systems, comprising but be not limited to the communication system of OFDM, CDMA and other types.