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 S01106, the second sector S11108 and the 3rd sector S21110.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 described 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 being distinguished 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 the S01106 of sector, a plurality of end node EN (1) 1116, EN (X) 1118 are coupled to base station 11102 via Radio Link 1117,1119 respectively.In the S11108 of sector, a plurality of end node EN (1 ') 1120, EN (X ') 1122 is coupled to base station 11102 via Radio Link 1121,1123 respectively.At sector S21110, a plurality of end node EN (1 ") 1124, EN (X ") 1126 is coupled to base station 11102 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 EN 1116,1118,1120,1122,1124,1126, and will carry out synchronously having different pilot signal transmission predetermined and known level between three sectors.According to the present invention, EN (1) 1116 this class end node can be to base station 1102 report feedback informations, and for example channel quality indicated value makes base station 1102 can determine 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 the peer node of 1104 outsides, sub-district to communicate thus.The EN of 1104 inside, sub-district 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 according to exemplary base station of the invention process (BS) 1200.Base station 1200 is more detailed expressions 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 be 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 described bus swap data and information.I/O interface 1208 then is coupled to base station 1200 internet and other network nodes.
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, received signal handling procedure 1260 and base station control program 1224.Received signal handling procedure 1260 has comprised this class received signal of report message that is used for from WT and has extracted the channel quality indicated value extraction module 1262 of channel quality indicated value, and is used for extracting the positional information extraction module 1264 of WT positional information from receiving message.In certain embodiments, the positional information indication is the position of WT with respect to sector borders.The channel quality indicated value that this class of SNR or performance number is extracted then offers transmit power calculation program 1226, so that used in for the process of calculated signals through-put power that is sent to WT.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 different power levels in tone 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 WT of the inside, sub-district that BS1200 and BS1200 served knows these pilot value.With the tone hopping sequences inside 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 tone 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 and the corresponding data message set of each wireless terminal that is operated in inside, 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 tone 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 by channel quality report messages, and the base station can use this message to calculate the expection SNR grade that receives as base station transmits signal power function on WT1.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 generation and received signal, scheduling and implement method step 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 and the receiver 1204 of the signal of travelling to and fro between wireless terminal to be controlled, 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 tone hopping sequences for each sector.Produce and the guide of transmission control procedure 1230 by means of pilot signal, the specific tone that can select to the tone power level that comprises in the power level information 1236 and for the specific tone that receives each pilot tone in each sector at special time is coordinated and is controlled.Shown in Figure 15～17,1230 pairs of tone transmission of program are controlled.The dedicated processes instruction of being responsible for transmitting different tones such as this class of software command can be independent assembly or module, here these assemblies and module can be construed to is independent device, and these devices control the base station by cooperation so that the pitch sequences of describing and showing in emission Figure 15～17.For example, in control transmission power, by 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 tone of varying level, the tone of for example known and predetermined fixed level, sectors zero tone and sub-district zero tone can obtain channel quality indicated value 1250 by the operation of calculating and so on thus from the measured signal value.According to the present invention, conventional (non-zero) tone, sectors zero tone and sub-district zero tone can be punchinged or replaces described 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 derives from channel quality indicated value 1250 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 of WT of offering is for the needs that receive SNR with capacity through-put power.
What Figure 13 described is according to exemplary wireless terminal 1300 of the invention process.Wireless terminal 1300 can be used as wireless end node, for example mobile node.Described wireless terminal 1300 is the EN1114,1116,1118,1120,1122 that shows in the example communications system 1100 of Figure 11,1124 more detailed expression.This wireless terminal 1300 has comprised receiver 1302, transmitter 1304, the processor such as CPU 1306 and memory 1308, and these parts are coupled by 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, and amplitude by measure receiving pilot signal and at least one item in the phase place are acquired.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 determine 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, described 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 sent 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, described 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 tone hopping sequences 1352 to wireless terminal.In addition, pilot signal power level information 1354 can also be discerned sector and sub-district zero tone.
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 identifies with base station IDs information 1344, hopping sequences information 1352 and tone information 1356.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.Described 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 received signal is determined the position of wireless terminal 1300 with respect to sector borders.And described 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.Described channel quality indicated value transmission control procedure 1333 comprises message generating module 1335.And described 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 at least two channel quality indicated values is included 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 described information in the message that comprises channel quality indicated value.The message that message generating module 1335 produces is to launch under the control of channel quality indicated value transmission control 1333.Here can interweave, for example substitute described 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 communication channel segmentation of transfer channel quality indicated value special use to launch message.In addition, this module 1333 can also control transmission times, so that should provide with the base station time and consistent by the preliminary election dedicated time slot of WT1300 use, stop other wireless terminals to use this dedicated time slot thus.
Fig. 1 is one and has shown and be used for the transmitter 101 that present invention is described and the sketch of 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, for 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, 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.WT203 measures downlink channel status 213 according to the pilot signal 209 that receives, and by 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, WT203 can follow the trail of and reporting channel state 213.And WT203 can and disturb estimating down-ward link channel state 213 according to the noise on received 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 normally with this single scalar of signal to noise ratio (snr) than form or of equal value measure the form report.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 determined correct (minimum) transmitting power from independent reception value.Yet unfortunately, for 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 described power.Usually have the component of " self noise " by name in noise, this component and signal power are proportional or roughly proportional.Fig. 3 has shown that a noise depends on the example of signal transmission power.In Fig. 3, chart 300 shows is the correlation reception signal power on the longitudinal axis 317 and the relation of the overall noise on the transverse axis 303.Wherein overall noise is represented with straight line 305, described 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 example is a unbalanced signal energy of disturbing received 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 with those noises that is independent of signal or greater than these noises the time, down link SNR value (can record on the pilot tone) deficiency of single scalar goes up 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 described method and apparatus can make each WT1300 predict on its down link 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 described 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 with straight line 305 simulations, and in this application this straight line are 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 determine this line 305, need for example two two parameters that channel quality indicated value is so at least.It is to determine the position of two dissimilaritys on the described 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 determined, 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 determining described straight line.
Pilot signal is launched in base station 1200 on down link.According to the present invention,, can determine the noise characteristic line of wireless terminal by the pilot signal of emission different intensity grades.Usually, first pilot signal sends 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 point 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, by 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.Will produce point 317 on the straight line 305 as second pilot signal of zero pilot signal, and identification zero pilot noise level 313, 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 records on pilot tone and zero pilot tone, WT1300 can obtain two different Noise Estimation 313,315 that are in unlike signal power, and wherein these two different signal powers can be zero energys and receive pilot power 317.In addition, WT1300 can also determine the complete noise characteristic line 305 among Fig. 3 from these two points 311,315.Then, WT 1300 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 indicated values.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 relative 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 different signal power P1 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 X1413 and X2417 represent respectively.The slope of straight line 405 and intersection point then are well-determined from X1413, X2417, Y1415 and Y2419.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 determined noise characteristic line 405 from the feedback information that receives, BS1200 can be the SNR on any given transmission power Q calculating WT receiver 1302 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:
By point (X2, P2) with (X1 carries out linear interpolation between P1), can provide the corresponding corresponding noise power with through-put power Q:
Then, by 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 numerical value of Y421 for the X-axis numerical value of X 420 and size, and to put A411 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 produces from the statistic of WT1300 report, BS1200 can determine 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 one exemplary 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 carrying out on different tones 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 tones 515 and zero tone 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 tones 515 and one zero tone 513 in Fig. 5, have been shown.The tone locations of pilot tone 515 and zero pilot tone 513 is all for known to BS1200 and the WT1300.In addition, also shown 26 data tones 511 in Fig. 5, they have corresponding transmission power level 509.As described in Figure 5, tone transmission power level 515 is apparently higher than data tones transmission power level 509, and this makes wireless terminal be easy to discern tone.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.
For 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 tone with the power P emission, the tone of data services is launched with power Q.So, WT1300 can measure SNR by 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 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 base station use power Q is carried out, and Q can be different from P.
The information that receives SNR is very important, because described reception SNR will determine the combination of supported code rate and modulation constellation ideograph.Concerning the target block error rate (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 be described, our hypothesis is proportional with the noise and the transmitting power of signal correction, and we have also used the noise characteristic line 305,405 that shows in Fig. 3 and 4 to characterize 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 represents is and noise that signal is irrelevant, and γ P represents is and the noise of signal correction that wherein γ is the proportionality factor of transmitting power P.So, when measuring euphonic SNR, 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 by calling this " SNR1 " its can be considered as an independent entity with the interference of those and signal correction.
By 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.By 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 noise with signal correction.Then, by using following formula, can provide the relation between SNR1 (P) and the SNR0 (P):
For the ease of mark, we define
By with Fig. 3 and 4 in the noise characteristic line compare, we as can be seen: what SNR0 (P) was corresponding is the intersection point of straight line and X-axis, 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) on the longitudinal axis 601 and the relation between the SNR0 (P) on the transverse axis 603, 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.The situation correspondence of SRR1=0 (line 605) be the irrelevant situation of noise and signal, so SNR1 (P)=SNR0 (P).The situation correspondence of SRR1=1 (line 609) be 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 replace by 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.As described in these derivations, by using zero pilot tone, WT1300 can determine statistic and it is transmitted into BS1200, so, even there is 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.For sectorized environment, the interference meeting between the sector 1106,1108,1110 produces 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 described 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 described power.Owing to do not isolate fully between the sector, therefore the signal of launching in a sector will become the noise (interference) of other sectors.In addition, if be forced to specify the degree of freedom to launch identical, proportional or almost proportional signal power each sector 1106,1108,1110, be that image signal correlated noise or self noise occur like that from other sectors and at the interference of the WT1300 in the designated sector 1106,1108,1110 so.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 come the intersection point of estimating noise characteristic curve in conjunction with the noise that all and signal have nothing to do.In addition, for instance, do not receive interference (or reducing the interference that is suffered) from other sectors by the WT1300 that the scheduling between the sector 1106,1108,1110 is coordinated, can be made to be in sector borders 1150,1152,1154.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 set on reverse link report 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 S0701 shown in Figure 7, S1703 and S2705.What Fig. 7 showed is the tone assignment of implementing for downlink transmission on the OFDM code element 707 of three sectors and appointment, the example that has wherein comprised the data tones position, for example exemplary data tones 728, and the example that has comprised tone locations, for example exemplary tone 728, the example that has comprised zero tone locations in addition, for example exemplary zero tone 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 execution modes, tone locations and order can change.
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 tone 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 S1703 of sector has corresponding with it tone 731 in the S0701 of sector, and has corresponding with it tone 737 in the S2705 of sector.
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 S0701 has 731,733,735,737 and sectors zero pilot tones 721 of four pilot tones and sub-district zero pilot tone 729.By 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 S0701 has unique pilot tone 735,727; And pilot tone 731 is shared a pitch frequency with the pilot tone 737 of sector S2705; And pilot tone 733 is shared a pitch frequency with the pilot tone 739 of sector S1703.In addition, the sectors zero pilot tone of a sector is consistent with tone in other sectors.For example, for the zero tone 725 among the S2705 of sector, pilot tone 733,739 is respectively to launch on the tone identical in sector S0701 and S1703.In addition, the position of tone, 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 example of the tone saltus step of pilot tone, sub-district zero pilot tone and sectors zero pilot tone.Chart 800 among Fig. 8 is 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 tone 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, tone is actually according to modular linear saltus step figure and comes saltus step.According to the present invention, sectors zero tone and the pilot tone saltus step of same slope value are according to identical modularization linear figure generation saltus step.In addition, in one embodiment of the invention, the pilot tone saltus step of sub-district zero tone and same slope value is according to identical molds blocking linear figure generation saltus step.
In one embodiment, data tones comes down to the modularization that changes according to a sequence linear saltus step figure and 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 identical molds blocking linear figure that sequence changes.In this embodiment, when sub-district zero tone and certain tone clash, wherein all can stop a tone transmission in each sector, and described tone will be removed efficiently, but at least in some sector, the transmission of tone will continue, and in fact sub-district zero tone 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.For the link from S0 to WT, receive SNR and provide so by following formula:
At the remainder of this argumentation, suppose that 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 tone can be used in the base station.In zero pilot tone of sub-district, the transmission of each sector all is zero, by using described sub-district zero pilot tone, can measure and the irrelevant noise of signal.In addition, compare, can provide following SNR by receiving intensity with itself and S0 pilot tone:
Next, in different embodiment, if one of them adjacent sectors is not carried out firing operation, the sectors zero tone can be used to measure SNR so.Especially, be the corresponding tone of sectors zero tone 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, by the euphonic SNR as the sectors zero tone among the S1 is measured, 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 tone 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
By 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 SNR can 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, for 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 by being that the tone of P is carried out to measure and is presented to transmitting power:
In Fig. 9, diagram 900 three kinds of situations that shown about the exemplary WT among the S0 of sector.Sub-district 901 comprises three sector S0903, S1905 and S2907.Fig. 9 has shown a WT909 near the border of sector S1905, and wherein WT 909 is subjected to the serious dl interference from sector S 1905.Sub-district 921 has comprised three sector S0923, S1929 and S2927, and this sub-district 921 has shown a center that is in sector S0923, and away from the WT929 of sector borders.Sub-district 941 has then comprised three sector S0943, S1945 and S2947, and its shows is WT949 near the border of sector S2941, and wherein WT949 has been subjected to coming the serious dl interference since sector S2947.
In one embodiment of the invention, in each situation in these three kinds of situations, WT can send a subclass 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.
The situation shown for reference cell among Fig. 9 901 supposes that WT909 among the S0903 of sector has been subjected to the serious interference from sector S1905.So, the coordinated scheduling device 1225 that is used for the base station can cut off sector S1905 and sector S0903 to the transmission of the WT909 transfer of data of mutual interference mutually.Simultaneously, by coordinating the transmission among the S2907 of sector, 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, by 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 shown situation of reference cell 921, 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 Fig. 9.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, for transmission,, can provide the SNR that WT929 experiences by using following formula from sector S0923:
In this case, as long as report SNR0 (P) and SRR2 can satisfy the demand.
Next, the shown situation of reference cell 941, WT949 is positioned near the sector borders of having a common boundary with sector S2947 in Fig. 9.Because WT949 has been subjected to the serious interference from sector S2947, so the coordinated scheduling device 1225 of base station 1200 can cut off the respective data transfer among the S2947 of sector.Simultaneously, suppose that the transmission of sector S1945 and transmission among the S0943 of sector are with identical transmitting power Q scheduling.So, by 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 an information subset need be transmitted into BS1200 from WT1300 in each structure in these three kinds possibility structures so.Especially, in one embodiment, wireless terminal 1300 is determined WT1300 present located situations (for example shown situation in the sub-district 921 among the sub-district among Fig. 9 901, Fig. 9 and the sub-district among Fig. 9 941).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 represents whether WT1300 is in the border and whether is necessary to cut off transmission in the adjacent sectors thus.Second bit can represent which sector in these two sectors produces more large disturbance.Hereinafter in the table 1 of being set forth, 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 reporting under the situation that has provided the corresponding report sector borders designator that same ranks lift.
|The sector borders designator
||The WT report
||Carry out firing operation in all sectors
||Cut off sector S2
||Cut off sector S1
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, the sector can 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 finished 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 Gan Raoing 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 correspondence of sectors type tabulation is its order (for example clockwise direction) that centers on the sector and advance.
|Number of sectors
|Number of sectors
By using above-mentioned sectors type scheme, the scheme that is used for three sector examples and has comprised sub-district zero pilot tone and sectors zero pilot tone can 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 feature also is applicable to non-cellular system.
In different embodiment, node as described herein is realized with one or more modules, carry out and the corresponding step of one or more methods of the present invention thus, 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 by 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, described machine-executable instruction can be a software, and described 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, described instruction impels the equipment of processor and so on and related hardware to carry out one or more steps in above-mentioned one or more method.
About description of the invention, those skilled in the art can know the numerous additional variation of understanding the foregoing invention method and apparatus according to above.These variations all are regarded as falling 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 different embodiment, mobile node be as notebook, personal digital assistant (PDA) or other those comprised receiver/transmitter circuitry and be used to implement the logical circuit of the inventive method and/or the portable equipment of program is realized.
Figure 14 describes is according to the present invention and launches the step of the exemplary method 1400 of tone with the method for synchronization in a plurality of sector of sub-district.This method starts from start node 1402 and proceeds to step 1404, will carry out initialization to current symbol time counter in this step, for example it is initialized as 1.In example system, code element is to send in the mode of code element one by one, symbol time then is the time that code element of emission and one-period prefix will be used, 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 launch those with the same tone and the method for synchronization according to the pilot transmission sequence of preliminary election in each sector 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 tone 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, slight timing slip might occur between the sector.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 which tone is used for tone 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 determined from power level information 1236.
In step 1406, in case launched tone 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, begins repetition pilot tone hopping sequences thus in step 1406.The cyclical transmission of tone will continue to repeat according to the tone hopping sequences implemented, 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 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, tone is launched simultaneously or almost simultaneously with same tone.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 tone of launching in the different sectors of sub-district.Unfortunately, as mentioned above,, 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 described signal measurement hypothesis is for each sector code element transmission time, a part of at least therein sector code element may occur overlapping fully in the transmission time.As mentioned above, 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 prefixes that are included in transmit symbol usually.
For discussing purpose, here suppose to exist fully synchronously, wherein this class signal of code element is that launch with the method for synchronization each sector in multi-sector cell simultaneously.Yet argumentation above shows that this precise synchronization can not occur usually and is not that enforcement is essential to the invention.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 tone with the method for synchronization on same set of tones, the tone power of different sectors will be controlled in the sub-district, so that permit different signal measurements, in particular sector, these measurements will help to determine from other sectors, for example noise contribution and the background noise of one or more adjacent sectors.
In order to help to carry out multiple different signal measurement, can use a plurality of 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 the different power level of allocation of pilots 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 tone transfer sequence of implementing in the one exemplary 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 slightly, but described 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 in order to launch the tone of 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 enumerating in row 1504 will be different.Yet if first to the 4th symbol time correspondence in the row 1502 is different current symbol times, the tone of enumerating in the row 1504 can be identical so, also can be different.
As mentioned above, 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, the tone of emission is all launched with previously selected through-put power at any time.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 described 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 described 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 the described biparting district of reference Figure 15 execution mode.
What each rectangle in the row 1506 and 1508 was represented is the step of using the regular code elementary time emission pilot signal of the tone of expression in the row 1504 and expression in row 1502 in indicated sector.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, using tone 1 and launched numerical value at symbol time 1 in the A of sector is 1 pilot signal, but what launch in the B of sector 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 decay among the accurate sector A of measurement under the situation of the interference that transmission caused that does not have sector B in addition.Row 1514 correspondences be symbol time 2, in this symbol time, tone 2 will be used in the A of sector emission zero tone, and will to be used in the B of sector emission numerical value be 1 pilot signal.Allow sector A to determine the signal interference volume that being transmitted among the B of sector caused on the same tone thus.Row 1516 correspondences be symbol time 3, in this symbol time, used tone 3 and in two sector A and B emission zero pilot signal, can measure the conventional background noise on the tone 3 thus.Row 1518 correspondences be symbol time 4, 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 transmits with identical non-zero power level can be measured simultaneously in each sector in each sector A and B.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 be as two different function inputs and essential by these two functions, wherein said function is used for producing first and second channel quality indicated values according to a feature 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 tone transfer sequence that is used for three sector systems.The same with the example among Figure 15, first row, 1602 correspondences be the code element transmission time, secondary series 1604 correspondences be tone, row 1606,1608 and 1610 then respectively the expression be three sector A, B that have in the sub-district, the pilot signal transmission in each sector among the C.Therefore, the same with the example 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 mentioned above, 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 has been each sector transmission in the execution mode of Figure 16 wherein will be used to launch emission zero pilot tone on the tone of described pilot signal in the adjacent sectors of described 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 described transmission time and other sectors is identical.
The same with the example 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, what each rectangle reality of enumerating on the title sector was corresponding is different symbol times, wherein the symbol time of each row is overlapping basically, and under the situation of precise synchronization, described symbol time equates.In the first to the 15 pilot tone P1～P15, the power level of each pilot tone represents in bracket that all for example, the through-put power of P1 is p1.Though some supports two different power levels in the situation of example as shown in figure 16, a plurality of known power levels equally also can be supported.Last column 1720 expression among Figure 17: in all cases, in each sector A, B and C, be zero according to these pilot signal power level and zero pilot signal transmission of using tone 5 to be carried out.
What chart 1750 shown in Figure 180 was described is the signal transmission of being carried out on 10 different tones 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 described 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 intrusion tone.Figure 19 describes is to come method 1800 that 1200 pilot signals that receive from the base station are handled by the operate wireless terminal, and wherein said pilot signal is launched according to the present invention.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 determining different noise contributions thus, wherein for instance, described 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 described 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 described 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 described 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.Described measurement will produce the second measured signal value, then, will use this value in step 1810.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 described 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 determined 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, by 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, described indicated value have with table 2 in shown certain of row 1 be worth corresponding value.Under having obtained from first and second channel quality indicated values of step 1806 and 1810 and situation from the boundary position indicated value of step 1814, operation will proceed to step of transmitting 1816, 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.First handles the path starts from substep 1820 and ends at step 1826, and what its was represented is the situation that has comprised different information in single message.Second handles the path starts from step 1830 and ends at step 1840, and the different message that is to use of its correspondence is launched the situation of each different value.In this environment, will explain synoptically, and these message have comprised the signal that is used to transmit the particular value that will transmit message.
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, the boundary position indicated value can be merged to first message.Then, in step 1816, described first message is delivered to base station 1200 by emission first message on wireless communication link.In different embodiment, this processing is to use from wireless terminal to finish 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, by 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 launching has certain preliminary election form on used control channel, in addition, and for instance, what described 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.The amount of overhead that so then this class of header overhead can be used to launch described message and/or numerical value reduces 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.
Step 1830 correspondence be 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 described 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 described 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 transmitting in step 1826, and the special-purpose segmentation that the single message of emission can be specifically designed to by 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, described method is used to launch tone and reception and handles feedback information, determines 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 S01106, S11108, S21110, so, in the process that tone 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 tones were launched in the essentially identical time.Tone transmission in the step 1904 is by using tone power level information 1236 and tone information 1238 and carrying out under the guide of pilot signal generation and transmission control procedure 1230.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.Described message is to receive under the guide of the received signal handling procedure 1260 that comprises in base station 1200.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 independent 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 independent 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 extracting from receive message 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 by operation.Be step 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 described 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 determining from described at least two channel quality indicated values 1250 that receive to transmit to described 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 described method will repeat.In step 1904, base station 1200 will be regularly be transmitted into pilot signal each sector in the multi-sector cell repeatedly with the method for synchronization.Yet, different wireless terminals 1300 can and/or comprise the message of the set of channel quality indicated value 1250 and sector borders positional information 1252 at different time with 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.