MXPA05008934A

MXPA05008934A - Pilotsignals for use in multi-sector cells

Info

Publication number: MXPA05008934A
Application number: MXPA/A/2005/008934A
Authority: MX
Inventors: Laroia Rajiv; L Fan John; Li Junyi
Original assignee: L Fan John; Flarion Technologies Inc; Laroia Rajiv; Li Junyi
Priority date: 2003-02-24
Filing date: 2005-08-22
Publication date: 2006-10-17

Abstract

Pilot signal transmission sequences and methods are described for use in a multi-sector cell. Pilots in different sectors are transmitted at different known power levels. In adjacent sectors a pilot is transmitted while no pilot is transmitted in the adjoining sector. This represents transmission of a NULL pilot signal. A cell NULL is also supported in which NULL pilots are transmitted in each sector of a cell at the same time. Multiple pilot signal measurements are made. At least two channel quality indicator values are generated from measurements corresponding to at least two pilot signals of different power levels. The two values are transmitted back to the base station which uses both valuesto determine the transmit power required to achieve a desired SNR at the wireless terminal. The wireless terminal also reports information indicating its location to a sector boundary.

Description

PILOT SIGNALS FOR USE IN MULTI-SECTOR CELLS Field of the Invention The present invention is directed to wireless communication systems, and more particularly, to methods and apparatus for transmitting pilot signals without a multiple sector cell, for example, a cell with synchronized sector transmissions. The present invention is directed to wireless communication systems, and more particularly to methods and apparatus for carrying out measurements of channel conditions.

Background of the Invention In wireless communication systems, for example, a cellular system, channel conditions are an important consideration in the operation of said system. Within a wireless communication system, a base station (BS) communicates with a plurality of wireless terminals (WTs), for example, mobile nodes. As a wireless terminal moves to different locations within the cell of the base station, the condition of the wireless communication channel between the base station and the wireless terminal may change, due for example to the various noise levels and interference. The noise and interference experienced by the wireless terminal receiver may include background noise, self-noise and inter-sector interference. The background noise can be classified as independent of the transmission power level of the base station. However, the interference of auto-noise and inter-sector depends on the transmission power level of the base station, for example, the transmission power in 0 one or more sectors. One method that is normally used to evaluate the condition of the communication channel is that the base station transmits pilot signals, which are signals normally transmitted in a small fraction of the transmission resource and are generally comprised of known (predetermined) symbols transmitted in a single level of constant power. The wireless terminal measures the pilot signals and reports to the base station in the form of a scalar ratio, such as a signal-to-noise ratio (SNR) 0 or equivalent metric. In the case where the noise / interference does not depend on the transmitted signal, for example, background noise is predominant and the contribution of the self-noise and inter-sector interference itself is negligible, said simple scalar metric is sufficient so that the BS anticipates how the received SNR will change, in the wireless terminal, with the signal transmission power. Subsequently, the base station can determine the minimum level of transmission power required to achieve a received SNR of acceptable level in the wireless terminal, for the coding scheme of particular error and modulation used. However, in the case where the total noise / interference includes a significant component that depends on the transmission power, for example, inter-sector interference of the base station transmissions in adjacent sectors, the commonly used technique of obtaining a SNR of the pilot signals of a fixed force level is insufficient. In this case, the information obtained, for example, the SNR in a single level of transmission power, through this commonly used technique, is insufficient and inadequate for the BS to accurately anticipate the SNR received in the WT as a function of signal transmission power. The additional channel quality information needs to be generated, collected by the wireless terminal and relayed to the base station, so that the base station can solve the function of the wireless terminals that relate to the received SNR for the power level of the base station. signal transmission from the base station. When obtaining said function from a communication channel of the wireless terminal, the programmer of the base station, knowing the acceptable level of SNR received for a particular coding range., error correction code and modulation used, could efficiently assign a wireless terminal segment in a channel with an adequate power level, thus achieving an acceptable SNR, limiting the wasted transmission power and / or reducing the levels general interference. Based on the previous discussion, it is clear that there is a need, particularly in the case of multiple sector wireless communication systems, of new and novel devices and methods to measure channel quality, evaluate and report what the base station will provide. with sufficient information to obtain the signal SNR received from the wireless terminal as a function of the transmitted power of the base station. In addition, to support improved and / or more diverse channel quality measurements, new patterns of the pilot signal, sequences and / or transmission power levels of the pilot signal that facilitate the analysis of auto-noise and interference of other signals are desirable. sectors of a cell.

Summary of the Invention Enhanced pilot signal sequences are provided which facilitate multiple channel quality measurements, for example, through the use of different levels of transmit power of the pilot signal. In several implementations, the transmitted pilot sequences facilitate the determination of the interference contribution of other sectors of a cell using the same tones, for example, in a synchronized manner, such as the sector in which the measurements of the pilot signal are being elaborated. . In cases where different sectors transmit in one tone at the same time using approximately the same power, the signals of the other sectors although they have interference can be observed as similar or equal to the self-noise, since the transmission power affects the amount of noise that will be found in the sector. To measure the noise contributions of the surrounding sectors, a sector NULA pilot signal, for example, a pilot signal with zero power, is transmitted in an adjacent sector at the same time as a pilot signal with a preselected power, not zero, and therefore known in the sector where the received pilot signal measurement is made. To facilitate measurements of background noise, a NULL cell is supported in some modes. In the case of a NULA cell, all sectors of a cell transmit a NULL pilot signal, in a tone that is used to measure background noise. Since no power is transmitted in the cell in the tone during the measurement, any signal measured in the tone is attributable to noise, for example, background noise that may include inter-cell interference. The measurements of the pilot signal sequences of the present invention provide mechanisms that allow a wireless (WT) terminal, and a BS that receives feedback information from the WT channel condition, to anticipate the link reception SNR. descending of the WT as a function of the signal transmission power in the presence of signal-dependent noise. The feedback of the individual WTs, according to the present invention, usually includes at least two channel quality indicator values per WT, as opposed to a single SNR value, where each of the two channel quality indicator values it is generated using a different function. One of the two generating functions of the channel quality indicator value has a first measurement of the pilot signal corresponding to a received pilot signal having a first known transmission power in the form of an input. A second of the two channel quality indicator generating functions has as an input, a second pilot signal measurement corresponding to another received pilot signal having a second known transmission power which is different from the first transmission power known Each of the first and second generating functions of the channel quality indicator value, which can be implemented as software modules or as hardware circuits, can also have additional inputs to those already mentioned. The feedback of the individual WTs, including at least two WT channel quality indicator values that are generated using different functions, allows the base station (BS) to transmit to different WTs in, for example, different minimum signal powers depending on the respective SNRs required in the receivers. The total power transmitted by the BS is usually known or fixed although the proportion assigned to the different WTs may be different and may vary with time. In a WT receiver, the dependence of a total noise as a function of the received signal power can be modeled through a straight line, referred to as the "noise characteristic line" in the present invention. Since the characteristic line of noise in general does not go through the origin, a single scalar parameter is not enough to characterize this line. At least two parameters are required to determine this line. The station transmits pilot signals on the downlink. According to the present invention, when transmitting pilot signals of different strength levels, the noise characteristic line of the wireless terminal can be determined. In general, a first pilot signal is transmitted at a first power level to obtain a first point, and a second pilot signal is transmitted at a second power level, different from the first power level, to obtain a second data point. The second power level can be zero in some modes. The previous pilot signal scheme can be used in a cell using an omni-antenna, that is, a cell with only one sector. The present invention further determines the SNR as a function of the signal transmission power in a sectorized cell environment. In a sectorization method, each of the different sectors of a cell can use the entire resource or almost the entire transmission resource (for example, frequency band) to transmit in each of the sectors. The total transmitted power of each sector is usually fixed or known, although different WTs can receive a signal with different power. Since the insulation between the sectors is not perfect, the signals transmitted in one sector can become noise (interference) for other sectors. In addition, if each of the sectors is restricted to transmit an identical or almost identical signal strength (or to transmit a signal power in a fixed proportion through different sectors) at a given degree of freedom (for example, slot time) the interference of other sectors for a WT in a given sector, has the characteristics of noise dependent on the signal or auto-noise. This is particularly the case when interference from other sectors is scaled with a signal strength that occurs in the mode where different sectors are restricted to transmit an identical or proportional power in a given degree of freedom, for example, tones in a OFDM multiple access system. In accordance with the present invention, regular pilot signals are transmitted at different known and predetermined strength levels from the base station to the wireless terminals to characterize the total noise dependence on a WT in the signal power through the BS to the WT. The different sectors can be, and often are, controlled to transmit at least some pilot signals in the same tone at the same time. Frequently the different sectors are controlled to use predetermined transmission power levels of the pilot signal transmitted in one tone in each of the sectors. For example, in tone 1 at time TI, a first sector can be controlled to transmit a pilot signal at a first power level although an adjacent sector is controlled to transmit at the same time TI, a pilot signal at a second level of power. power in tone 1, with the second power level of the first power level being different. According to one embodiment of the present invention, "null pilot signals from cells" are used in conjunction with regular pilot signals to characterize the total noise dependence on a WT in the power of the signal transmitted through the BS to said WT . The null pilot cell signals are downlink resources (degrees of freedom) where none of the sectors of the cell transmits any power. The noise measured in these degrees of freedom provides an estimate of the noise independent of the signal in the WT. Regular pilot signals (or simply pilots) are resources (degrees of freedom) where each sector of the cell transmits known symbols using fixed or predetermined powers. The noise measured in the pilots includes inter-sector interference and provides an estimate of the total noise, including signal-dependent noise. A feature of the present invention is directed to the concept of a "null sector pilot signal". No pilot sector signals can be used in a sectorized wireless cellular system to estimate the noise in the WT, for example, when the WT is at the limit of two sectors and the programming is coordinated between the sectors so that the WT in the limit does not receive any interference from the other sector. The null pilot signal of the sector may be downlink resources where one sector in a cell does not transmit any signal energy, and the rest of the sectors or an attached sector transmits regular pilot signals, for example, not zero. More generally, other types of sector null pilot signals can be defined, such as where a subgroup of the sectors of a cell does not transmit a signal in the downlink resources and in the rest of the sectors transmits regular pilot signals. Also, more generally coordinated programming between sectors can be such that the BS reduces (although not necessarily eliminates) the transmission power in some sectors in order to reduce the interference that a WT receives from other sectors. In some cases, the data is transmitted in a tone in a sector adjacent to a sector which transmits a pilot signal in the tone. With the help of several pilots of regular strength and / or various types of null pilot, a WT can estimate the noise in the receiver as a function of the power of the signal transmitted to said WT under various conditions. The present invention also refers to the communication of this information from the WT to the BS, in order to allow the BS to determine the power that will be used to transmit to the different WTs in both omni-cell and sectorized cellular environments . Unlike the prior art, the channel quality information is not a single scalar value, but includes two or more values that can be used to reflect the effect of the noise itself and / or inter-sector noise in addition to background noise . In one embodiment of the present invention for a wireless cellular system based on OFDM, the pilots include known symbols that are transmitted by the base station in specific tones (and specific symbol times) at a fixed or predetermined power, and the pilots Nulls are usually tones that are left empty, for example, with zero transmission power. In a modality used in an omni-directional antenna deployment, here known as an "omni-cell", the WT measures the SNR in the pilot tones, which includes all sources of noise / interference, including the noise that depends on the pilot transmission power. In addition, the WT also measures noise using the tone (s) of the cell's null pilot signal. Taking the proportion of the pilot power received with this noise measurement, a SNR is provided that is limited to noise / interference regardless of the signal. The WT transmits back to the BS these two SNR values, or some combination of equivalent statistics. In the modality of a sectorized deployment with different sector antennas, a single cell is divided into multiple sectors, some or all of which may share the same frequency band (degrees of freedom) that correspond to a frequency reuse of 1. In this situation, in addition to the null pilot signal of the cell, the present invention describes the use of sector null pilot signals that are in a subset of sectors but not in all sectors, and also provides a pattern for pilot tones so that a null pilot tone in a sector is synchronized by time / frequency with a pilot tone in some or all other sectors. This allows the WT to measure two or more ratios of signal to noise, which include interference from different combinations of sectors. In a reverse link, the WT reports a group of statistics related to the SNR, which allows the BS to estimate these SNR levels received in a WT as a function of the transmit power of the base station. The BS uses the quality values of the reported channel to determine the level of power in which it is transmitted to achieve a desired SNR in the WT. In accordance with the present invention, a wireless terminal performs measurements of at least two different received pilot signals, which were transmitted at different first and second preselected power levels, and thus known. The two power levels can be, for example, a non-zero power level and a zero power level although other power level combinations are possible without a power level being a mandatory requirement. of zero power. The value obtained from measuring the first received pilot signal is processed through a first function to produce a first indicator value of the channel quality. The second measured signal value obtained from measuring the second received pilot signal is processed through a second function, which is different from the first function, to produce a second value indicating the channel quality. The first and second channel quality indicator values are transmitted from the wireless terminal to the base station. In some modalities, a single message is transmitted, although in other modalities it is transmitted in separate messages. The channel quality indicator values can be SNR values or power values. Therefore, the first and second channel quality indicator values can be both SNR values, they can be both power values or one can be a SNR value and one a power value. Other types of values can also be used in the indicator values of the channel quality, with the SNR and the power values being an example. In some modalities, the WT determines its location in relation to a sector boundary and reports this location information to the base station. The location information is reported to the base station. The reported location information is usually in addition to the two channel quality indicator values that are sometimes sent as a separate message. However, in some cases, the location information is transmitted in the same message as the two channel quality indicator values. In the detailed description that follows, numerous features, benefits and additional embodiments of the methods and apparatus of the present invention are described.

Brief Description of the Figures Figure 1 is a simplified diagram showing a transmitter and a receiver used to explain the present invention. Figure 2 shows an exemplary wireless cellular system. Figure 3 shows an example where the noise depends on the transmitted signal power and is used to explain the present invention. Figure 4 shows an example of an exemplary noise characteristic line, showing the received power versus total noise, and is used to explain the present invention. Figure 5 shows a power versus frequency plot corresponding to an example embodiment of the present invention illustrating data tones, non-zero pilot tones and a null pilot tone. Figure 6 is a graph illustrating the relationship between SNR1, a SNR received at the wireless terminal that includes signal-dependent and signal-independent noise, and zero SNR, a SNR received at wireless terminals that does not it includes noise dependent on the signal in three cases: where the noise is independent of the signal, where the noise dependent on the signal is equal to the signal, and where the noise dependent on the signal is less than that of the signal. Figure 7 shows an exemplary signaling of an OFDM mode of three sectors of the present invention illustrating non-zero pilot tones, pilot null sector tones and null pilot cell tones in accordance with the present invention. Figure 8 illustrates an example of a tone jump of the non-zero pilot signals, sector null pilot signal and null pilot cell signals according to the present invention. Figure 9 illustrates three situations of an exemplary wireless terminal in a three-sector mode used to explain the present invention with respect to the boundary information aspects of the sector of the present invention. Figure 10 illustrates a scheme using three types of sector, which are repeated for cases with cells comprising more than three sectors according to the present invention. Figure 11 illustrates exemplary communication systems that implement the present invention. Figure 12 illustrates an exemplary base station implemented in accordance with the present invention. Figure 13 illustrates an exemplary wireless terminal implemented in accordance with the present invention.

Figure 14 illustrates steps for transmitting pilot tones in multiple sectors of a cell in a synchronized manner according to the present invention. Figures 15 to 17 illustrate exemplary pilot tone transmissions together with pilot signal transmission power information in accordance with the present invention. Figure 18 illustrates a graph showing the transmission of signals in ten different tones during a single period of transmission of symbols according to the present invention. Figure 19 is a flowchart illustrating the operation of an exemplary wireless terminal that implements the methods of the present invention. Figure 20 is a flow chart illustrating the operation of an exemplary base station implementing the methods of the present invention.

Detailed Description of the Invention The methods and apparatus of the present invention are well adapted for use in a wireless communication system, which utilizes one or more multiple sector cells. Figure 11 illustrates an exemplary system 1100 with a single cell 1104 shown, although it should be understood that the system can, and often does, include many of said cells 1104. Each cell 1104 is divided into a plurality of sectors N, wherein N is a positive integer greater than l. The system 1100 illustrates the case where each cell 1104 is subdivided into 3 sectors: a first sector SO 1106, a second sector SI 1108 and a third sector S2 1110. Cell 1104 includes a sector limit S0 / S1 1150, a limit sector S1 / S2 1152 and sector limit S2 / S0 1154. Sector boundaries are limits where signals from multiple sectors can be received, for example, union sectors at almost the same level, which makes it difficult for a receiver to distinguish between • transmissions of the sector in which it is located and the sector attached. In cell 1104, multiple end nodes (ENs) for example wireless terminals (WTs), such as mobile nodes, communicate with a base station (BS) 1102. Cells with two sectors (N = 2) and more are also possible. of three sectors (N > 3). In the SO 1106 sector, a plurality of end nodes EN (1) 1116, EN (X) 1118 are coupled to the base station 1 1102 via the wireless links 1117, 1119, respectively. In SI sector 1108, a plurality of end nodes EN (l ') 1120, EN (X') 1122 are coupled to base station 1 1102 via wireless links 1121, 1123, respectively. In the sector S2 1110, a plurality of end nodes EN (1") 1124, EN (X") 1126 are coupled to the base station 1 1102 through the wireless links 1125, 1127, respectively. In accordance with the present invention, the base station 1102 transmits pilot signals at multiple power levels to the ENs 1116, 1118, 1120, 1122, 1124, and there is synchronization of the transmission of pilot signals of various predetermined and known levels among the three sectors. In accordance with the present invention, the end nodes, for example EN (1) 1116, report feedback information, eg, channel quality indicator values to the base station 1102, allowing the base station 1102 to determine the received SNR by wireless terminals as a function of the signal strength transmitted by the base station. The base station 1102 is coupled to a network node 1112 through a network link 1114. The network node 1112 is coupled to other network nodes, eg, intermediate nodes, another base station, 7AAA nodes, agent nodes local, etc., and the Internet through the network link 1129. The network node 1112 provides an external interface cell 1104, so that the ENs operating within the cell can communicate with similar nodes outside the cell 1104 The ENs within the cell 1104 can move within sectors 1106, 1108, 1110 of cell 1104 or can move to another cell corresponding to the base station. The network links 1114 and 1129 can be, for example, fiber optic cables. Figure 12 illustrates an exemplary base station (BS) 1200, implemented in accordance with the present invention. The base station 1200 is a more detailed representation of a base station 1102 shown in the example communication system 1100 of FIG. 11. The base station 1200 includes sectorized antennas 1203, 1205 coupled to the receiver 1202 and the transmitter 1204, respectively. The receiver 1202 includes a decoder 1212, while the transmitter 1204 includes the encoder 1214. The base station 1200 also includes an interface 1/0 1208, a processor, for example CPU, 1206 and memory 1210. The transmitter 1204 is used for transmitting pilot signals from multiple sectors in a synchronized manner through the sectorized transmission antenna 1205. The receiver 1202, the transmitter 1204, the processor 1206, the I / O interface 1208 and the memory 1210 are coupled together via bus 1209 through which the various elements can exchange data and information. The I / O interface 1208 couples the base station 1200 to the Internet and to the other network nodes. Memory 1210 includes routines 1218 and information / data 1220. Routines 1218, when run through processor 1206, may cause base station 1200 to operate in accordance with the present invention. Routines 1218 include communication routine 1222, a received signal processing routine 1260, and base station control routines 1224. The received signal processing routine 1260 includes a module for extracting the quality indicator value from channel 1262 that extracts the channel quality indicator values from the received signals, for example, WT report messages, and an information extraction module position 1264 to extract the WT position information from received messages. The position information, in some modalities, indicates a position of the WT relative to a sector boundary. The extracted channel quality indicator values, for example SNR or power values, are provided to the transmission power calculation routine 1226 to be used in the calculation of the transmission power of the signals transmitted to a WT. The control routines of the base station 1224 include a programmer module 1225, a transmission power calculation routine 1226 and signaling routines 1228 that include a transmission generation control routine of a pilot signal.

The data / information 1220 includes data 1232, pilot jump sequence information 1234 and data / information from the wireless terminal 1340. The data 1232 may include data from the decoder of the receiver 1212, data that will be sent to the encoder of the transmitter 1214, results of intermediate processing steps, etc. The pilot jump sequence information 1234 includes power level information 1236 and tone information 1238. The power level information defines the different power levels that may be applied to the different tones in order to generate pilot signals of various forces, within the pilot tone jump sequence according to the present invention. These pilot values are adjusted, for example, pre-selected fixed values, before transmission and are known for both the BS 1200 and the WTs in the cell served by the BS 1200. The tone information 1238, includes information that defines which tones should to be used as pilot tones at a specific strength level, what tones should be null tones of the sector, and what tones should be null cell tones, within the pilot tone jump sequence of each sector for each terminal ID 1246 The data / information of the wireless terminal 1240 includes groups of data information for each wireless terminal operating within the cell, information WT 1242, information WT N 1254. Each group of information, for example, information WTl 1242 includes data 1244 , Terminal ID 1246, sector ID 1248, channel quality indicator values 1250 and sector limit position information 1252. Data 1244 includes data from the received from the WT 1 and user data that will be transmitted to a similar node that communicates with the WTl. The ID of terminal 1246 is an Identification assigned to the base station that has been assigned to WT 1; a specific pilot tone jump sequence, including various pilot signal strengths at predetermined times, that are generated at the base station corresponding to each specific terminal ID 1246. The ID of the sector 1248 identifies which of the three SO sectors, YES, S2, WT 1 is operating. The channel quality indicator values 1250 include information carried by the WT1 to the base station in the channel quality report messages, which can be used by the base station to calculate the received SNR WT1 level expected as a function of the transmit signal strength of the base station. The channel quality indicator values 1250 are derived by the WT1 from the measurements carried out by the WT1 in pilot signals of various forces transmitted by the base station, according to the present invention. The position information of the boundary of sector 1252 includes: information that identifies if the WTl has identified that it is near a sector boundary, that it is experiencing high levels of interference and information that identifies that WTL of sector boundary is located nearby. This information is obtained or derived from the position feedback information transmitted by the WTl received by the BS. The channel quality indicator values 1250 and the sector limit position information 1252 represent the quality feedback information of the WT1 channel to the base station 1200, providing information regarding one or more downlink channels between the 1200 base station and the WTl. The communication routines 1222 are used to control the base station 1200 to carry out various communication operations and implement various communication protocols. The control routines of the base station 1224 used to control the 1200 base station, carry out a basic function of the base station, for example, signal generation and reception, programming and implement the steps of the method of the present invention that include generation of pilot signals at different levels of transmission, reception and processing strength and use of information reported by the wireless terminal. The signaling routine 1228 controls the transmitter 1204 of the receiver 1204 that generates and detects signals to and from the wireless terminals, for example, OFDM signals that follow sequences of data pitch jumps. The generation and transmission control routine of the pilot signal uses the data / information 1220, which includes the pilot signal jump sequence information 1234, to generate specific pilot tone jump sequences for each sector. The power levels of the pilot tones, included in the power level information 1236 and the specific tones selected to receive specific pilot tones for each pilot signal in each sector at specific times, are coordinated and controlled under the direction of the routine. generation and transmission control of pilot signal 1230. This routine 1230, controls the transmission of pilot tones, for example, as illustrated in figures from 15 to 17. Individual processing instructions, for example, software commands , responsible for the transmission of different pilot tones, are individual components or modules that can be interpreted as separate means that operate together to control that the base station transmits the pilot tone sequences that are described and shown in the figures of 15 a 17. The coordination and / or synchronization of the transmission of several types of pilot signals between the sectors of a For example, in terms of transmission frequency, and / or symbol transmission time, although the transmission power is controlled, it allows a wireless terminal to receive the various levels of transmitted pilot tones, for example, fixed level pilot tones. known defaults, sector null pylons and null pilot cell tones, to obtain, for example, computerized from the measured signal values, channel quality indicator values 1250. In accordance with the present invention, the regular pilo tones (non-null), null sector pilot tones and null cell pilot tones can be drilled or replace data tones that could normally be transmitted. The programming module 1225 is used to control the transmission programming and / or the allocation of programming resources. Programmer 1225, according to the present invention, may be supplied with information indicating each SNR received from the wireless Terminal as a function of the transmitted signal power of the base station. Said information, derived from the channel quality indicator values 1250, can be used by the programmer to assign channel segments to the WTs. This allows the BS 1300 to allocate segments on channels that have sufficient transmission power to meet the SNR requirements received from a particular data range, coding scheme, and / or modulation, selected to be provided to a WT. Figure 13 illustrates an exemplary wireless terminal 1300, implemented in accordance with the present invention. The wireless terminal 1300 can be used as a wireless end node, for example, a mobile node. The wireless terminal 1300 is a more detailed representation of the ENs 1114, 1116, 1118, 1120, 1122, 1124 shown in the example communication system 1100 of Figure 11. The Wireless Terminal 1300 includes a receiver 1302, a transmitter 1304, a processor, for example, CPU, 1306, and memory 1308 coupled together via bus 1310, by which elements can exchange data and information. The wireless terminal 1300, includes receiving and transmitting antennas 1303, 1305 which are coupled to the transmitter and receiver 1302, 1304, respectively. The receiver 1302 includes a decoder 1312, while the transmitter 1304 includes an encoder 1314. The processor 1306, under the control of one or more routines 1320 stored in the memory 1308, causes the wireless terminal 1300 to operate in accordance with the methods of the present invention, as described above. The memory 1320 includes routines 1320 and data / information 1322. The routines 1320 include communication routine 1324 and control routines of the wireless terminal 1326. The control routines of the wireless terminal 1326 include signaling routines 1328 that include a modulation module. measurement of the pilot signal 1330, a module for generating the quality indicator value of the channel 1332, a module for determining the position of the boundary of the sector 1331, and a transmission control module for the quality indicator value of the channel 1333. The data / information 1322 includes user data 1334, for example, information that will be transmitted from wireless terminal 1300 to a similar node, user information 1336 and pilot signaling information 1350. User information 1336 includes information of measured signal values 1337 , information of the quality indicator value 1338, sector limit position information 1340, in terminal ID formation 1342, base station ID information, channel reporting information 1342. Pilot signaling information 1350 includes jump sequence information 1352, power level information 1354 and tone information 1356. The Measured signal value information 1337 includes measured signal values obtained from the measurements, carried out under the control of the pilot signal measurement module 1330 of at least one of an amplitude and phase of a received pilot signal. The information of the quality indicator value 1338 includes the output of the generation module of the quality indicator value of the channel 1332. The information of the channel quality indicator value 1338, when transmitted to a base station may allow the base station to determine the SNR received by the WTs as a function of the transmitted signal strength. The boundary position information of sector 1340 includes information identifying the wireless terminal that is in a sector boundary region, for example, the wireless terminal is experiencing high levels of inter-sector interference, and information that identifies which of the two adjacent sectors is the sector of the boundary region. The base station can use the sector boundary information to identify the channels in the adjacent sectors, where the transmission power must be turned off to reduce inter-sector interference. The report information of channel 1346 includes the indicator values of the 1338 quality channel obtained, or parts of the indicator values of channel 1338 and may also include position information of the boundary of sector 1340. The reporting information of channel 1346 can be structured with individual messages for each quality indicator value or with groups of quality indicator values included in a single message. Messages can be sent periodically at predetermined times on dedicated channels. The ID information of the terminal 1342 represents an identification assigned to the base station applied to the wireless terminal 1300, while it is operating within the cellular coverage area of the base station. The base station ID information 1344 includes information specific to the base station, for example, a slot value in a jump sequence, and may also include sector identification information. The information of the pilot jump sequence 1352 identifies a determined base station with the base station ID information 1344, whose tones 1356 at that time, for example, the time of the OFDM symbol, must be measured to evaluate the pilot signals. The power level information of the pilot signal 1354 identifies the wireless terminals, the transmission levels of the pilot signals in the tones of the assigned pilot signal 1356 included in the 1352 pilot tone jump sequence. 1354 pilot signal power can also identify null pilot tones of the sector and the cell. The communication routines 1324 are used to control the wireless terminal 1300 to carry out various communication operations and implement various communication protocols. The control routines of the wireless terminal 1326 control the basic functionality of the wireless terminal 1300 in accordance with the methods of the present invention. The signaling routines of the wireless terminal 1328 control the basic functionality of the wireless terminal signaling which includes the control of the receiver 1302, transmitter 1304, signal generation and reception and controls the operation of the wireless terminal in accordance with the methods of the present invention, which include the measurement of the pilot signals, the generation of indicator values and the transmission of channel quality indicator values. The measurement module of the pilot signal 1330 controls the measurement of the received pilot signals, identified by the base station ID information 1344, jump sequence information 1352 and tone information 1356. The measurement routine of the pilot signal 1330 measures at least one of an amplitude and a phase of a pilot signal to produce a measured signal value corresponding to each measured pilot signal. The indicator value of the channel generated by module 1332 includes a power estimation module 1361 and an estimation module SNR 1362. The module for generating the indicator value of channel 1332 generates quality indicator values according to functions, which use measured signal values 1337 produced from the pilot signal measurement module 1330. The module 1332 includes first and second sets of instructions for implementing first and second value functions of the channel quality indicator where the first and second functions are different. The power estimation module 1361 includes software instructions for controlling the processor 1306 to estimate the received power included in the received pilot signal (s). The SNR estimation module 1362 includes software instructions for controlling the processor 1306 to estimate the signal to noise ratio of the received pilot signal (s). The sector limit determination module 1331 determines the position of the wireless terminal 1300, relative to a sector limit of the information included in the received signals. The sector boundary position determination module 1331 can also distinguish that boundary of the adjacent sector that is closest to the wireless terminal and which adjacent sector is causing higher levels of interference with respect to the WT 1300. The information output of the module sector limit position determination 1131 is included in the position information of the boundary of sector 1340. The transmission control routine of the channel quality indicator value 1333 controls the transmission of channel quality value and information from the boundary of the sector to the base station. The transmission control routine of the channel quality indicator value 1333 includes a message generation module 1335. The message generation module 1335 controls the processor 1306 using machine executable instructions to generate messages used to communicate values indicating the quality of the message. channel . The message generation module 1335 can generate messages with a single channel quality indicator value or include at least two channel quality indicator values in a single message. The message generation module 1335 can also generate messages, which include position information, for example, limit position information of sector 1340 or incorporate said information into a message that includes a channel quality indicator value. The messages, generated by the message generation module 1335, are transmitted under the control of the transmission control module "of the quality indicator value of the channel 1333. The messages corresponding to the first and second values can be interleaved, for example, alternating for transmission purposes The transmission control module of the channel 1333 quality indicator value periodically transmits messages in some modalities using segments of the communication channel dedicated to carry the channel quality indicator values. control the transmission times to correspond with the pre-selected dedicated time slots dedicated by the base station to be used by a WT 1300, thus excluding other wireless terminals from using the dedicated time slots .. Figure 1 is a diagram simplified showing a transmitter 101 and a receiver 103 which will be used to explain the present invention. The transmitter 101 may be, for example, the transmitter 1204 of the base station 1200, while the receiver 103 may be, for example, the receiver 1302 of the wireless terminal 1300. In a communication system, such as the system 1100, the transmitter 101 often needs to make choices with respect to the proper method for transmitting data to the receiver 103. The selections may include the code range of the error correction code, the modulation constellation and the transmit power level. In general, in order to make sensitive choices, it is desirable that the transmitter 101 be aware of the communication channel of the transmitter 101 to the receiver 103. FIG. 1 shows an example system 100, in which the transmitter 101 sends data traffic 102 to a receiver 103 on a direct link 105. On a reverse link 107 of the receiver 103 to the transmitter 101, the receiver 103 reports the condition of the direct link channel 106 to the transmitter 101. Subsequently the transmitter 101 uses the information of reported channel condition 106 to adjust its parameters in an appropriate manner for transmission. Figure 2 shows an exemplary wireless cellular system 200 in which a transmitter is included in a base station (BS) 201 with the antenna 205, and a receiver is included in a wireless (WT) terminal 203, for example, a terminal mobile or a fixed terminal with the antenna 207, allowing the base station 201 to communicate the information in the downlink channel (s) 208 to the wireless terminal 203. Frequently the BS 201 transmits pilot signals 209, which are normally transmitted in a small fraction of the transmission resource and are generally comprised of known (predetermined) symbols transmitted at a constant power. The WT 203 measures the condition of the downlink channel 213 based on the received pilot signals 209, and reports the conditions of the channel 213 to the BS 201 on an uplink channel 215. It should be noted that since the channel conditions 213 often change over time due to fading and Doppler effects it is desirable for BS 201 to transmit pilots 209 frequently or even continuously so that WT 203 can track and report the conditions of channel 213 as they vary with time. The WT 203 can evaluate the conditions of the downlink channel 213 based on the received signal strength and the noise and interference in the pilot signals 209. The combination of noise and interference will subsequently be referred to as "noise / interference" or just as "noise". In prior art techniques, this type of information is usually reported in the form of a single scalar proportion, such as the signal to noise ratio (SNR) or an equivalent metric. In the case where the noise / interference does not depend on the transmitted signal, said simple scalar metric is usually all that is referred to in BS 201 to anticipate how the received SNR will change with the signal transmission power. In this case, BS 201 can determine the correct (minimum) transmission power for the coding and modulation that it selects to transmit from "the only received value." Unfortunately, in the case of multiple sector, the noise that results from the signals transmitted may be a significant signal component that makes a single scalar value insufficient for precise SNR predictions for different levels of transmission power, in many communication situations, especially in cellular wireless systems, such as the multi-sector system 1100 of the present invention, the noise is not independent of the signal transmission power, but depends on it.There is generally a noise component called "auto-noise", which is provided or strictly proportional to the power of the signal. Figure 3 shows an example where the noise is dependent on the transmit power of the signal. ra 3, in graph 300 the received power of the signal of interest is shown on the vertical axis 317 versus the total noise on the horizontal axis 303. The total noise, represented by the line 305 which is the sum of the dependent part of the signal 309 and an independent part of the signal 307, is plotted against the received signal strength 317. There can be many reasons for self-noise. An example of auto-noise is the non-equalized signal energy that interferes with the received signal. This noise is proportional to the strength of the signal. The energy of the non-equalized signal can result from the error in the channel estimate or the error of the equalizer coefficients or for many other reasons. In situations where auto-noise is comparable to, or greater than, signal-independent noise, a single scalar downlink SRN value (which can be measured in a pilot signal) is no longer adequate for the BS 1200 to anticipate precisely the SNR received in the WT 1300 as a function of the transmit power of the signal. The present invention provides methods and apparatus that allow each WT 1300 to anticipate its downlink reception SNR as a function of the transmit power of the signal in the presence of signal-dependent noise 309 and communicates this information to the BS 1200 This allows the BS 1200 to transmit to different WTs in different (minimum) signal strengths depending on the respective SNRs required in each of the WTs. The total power transmitted by the BS 1200 is usually known to be fixed although the proportion assigned to the different WTs 1300 may be different and may vary with time. In a WT receiver 1302, the total noise dependence 303 as a function of the received signal strength 1317 can be molded by a straight line 305, referred to as the "noise" characteristic line in this application, as shown in FIG. Figure 3. Since the noise characteristic line 305 in general does not pass through the origin, a single scalar parameter is not sufficient to characterize this line 305. At least two parameters are required, for example, two channel quality indicator values. to determine this line 305. A simple method to determine this line is to identify the location of two different points, for example, points 311 and 315, since any of the two different points determine only a straight line. a practical matter, the points can be determined with limited precision, so that the precision with which the line is determined is better if the points are chosen separately or that if the points are chosen together. The base station 1200 transmits pilot signals in downlink. In accordance with the present invention, by transmitting the pilot signals at different strength levels, the noise characteristic line of the wireless terminal can be determined, in general, a first pilot signal is transmitted at a first power level to obtain a first point, and a second pilot signal at a second power level, different from the first power level, to obtain a second data point. The first and second pilot signals can be transmitted at the same time if different tones are used for each pilot signal. With respect to Figure 3, the first pilot signal is measured and processed to produce the first point 315 on line 305 which identifies the received pilot signal power level 317 and a corresponding total noise level 319. According to an embodiment of the present invention the BS 1200 transmits "null pilot" signals in the downlink in addition to the non-zero pilot signals. The null pilot signals are comprised of transmission resources (degrees of freedom) where the BS 1200 does not transmit a signal power, for example it transmits a pilot signal having zero power. The second pilot signal, the null pilot signal results in point 311 on line 305 and identifies the noise level of pilot signal null 313 which is equivalent to the independent noise of signal 307. Based on the noise measured in both the pilot signals as in the null pilot signals the WT 1300 obtains two different noise estimates 313, 315 in two different signal powers, for example power 0 and received pilot power 317. From these two points 311, 315 the WT 1300 can determine the entire characteristic line 305 of Figure 3. The WT 1300 can subsequently also communicate the parameters of this line 305 (eg, slot and intercept, or some other equivalent information group) of the BS 1200 that allows the BS 1200 determine the SNR received for a given transmission signal power when transmitting to the WT 1300 which reported multiple channel quality values. Since the null pilot signals have zero signal power and other pilot signals, on the other hand, the two points 311, 315 corresponding to the null pilot signal and the non-zero pilot signal in the signal are normally transmitted with a relatively large power. 3, are relatively separate which leads to a good accuracy in the characterization of line 305. The signal noise and the various signaling emissions will be debed further. The graph 400 of Figure 4 traces the received power of a signal of interest on the vertical axis 401 versus the total noise on the horizontal axis 403. Figure 4 provides an illustration of a noise characteristic line of example 405. To characterize the line 405, according to the present invention, the BS 1200 transmits signals that allow the WT 1300 to make measurements from at least two different points on the line, for example points 407 and 409, information, which characterizes line 405 obtained from said measurements and subsequently "transmit it to the BS 1200. For example, the BS 1200 can transmit two different signal powers Pl and P2 that will be received as the powers Yl and Y2, as shown in Figure 4. The WT 1300 it measures the corresponding received signal powers, denoted as Yl 415 and Y2 419, and the corresponding total noise, denoted as XI 413 and X2 417, respectively From XI 413, X2 417, Yl 415, and Y2 419, the slot d and intercept of line 405 can be uniquely determined. In one modality, Pl and P2 are known and fixed. In another embodiment, P2 can be the pilot power corresponding to a pilot signal, while Pl can be zero, representing a null signal, which occupies some transmission resources but with zero transmission power. However, in general, Pl does not necessarily have to be zero. For example, Pl can, and in some modalities is a positive number less than P2. Once the 405 noise characteristic line has been determined through the BS 1200 from the received feedback information, the BS 1200 can calculate the SNR at the WT receiver 1302 for any given transmission power Q. For example, FIG. 4 shows the method of determining the SNR corresponding to a given transmission power Q. First, the BS 1200 finds the corresponding received signal power Y 421 of the transmission power Q, interpolating in a linear fashion between the points (Y2, P2) and (Yl, Pl): Y = Yl + Y2 ~ Yl - (Q-P?).

The corresponding noise power, which corresponds to a transmission power Q, is determined by linear interpolation between the points (X2, P2) and (XI, Pl): P2-P1 ^ 'Subsequently the SNR (Q), the SNR as observed by the WT 1300 for a transmission power Q of the BS is determined by: SNRÍO) = - = r? (P2-pi) + (r2-y?) (< 3-p?) \\ ¿) X_ l (2-Pl) + (Z2-ZiX (2- l) The point A 411 in the noise characteristic line 405 shown in Figure 4 has the value of the x-axis of X 420 and the value of the y-axis of Y 421 and corresponds to the transmission power Q. The slot of the a line connecting point A 411 and source 422 in SNR (Q), SNR in receiver WT 1302 if the transmission power Q is used. Subsequently, from the noise characteristic line 405 generated from the statistics reported from the WT 1300, the BS 1200 can and determines, for example, what transmission power is required to meet a given SNR requirement for the WT 1300. Figure 5 shows a graph 500 that traces the power on the vertical axis 501 vs. the frequency on the horizontal axis 503. Figure 5 corresponds to an example embodiment of the present invention, in which the wireless cellular network uses Orthogonal Frequency Division Modulation (OFDM). In this example case, the frequency 505 is divided into 31 orthogonal tones, so that the transmissions in different tones do not interfere with each other in the receiver, even in the presence of a multipath fading in the channel. The minimum unit of signal transmission is a single tone in an OFDM symbol, which corresponds to a combination of time and frequency resources. Figure 5 shows the power profile of the tones in a given OFDM symbol. In this embodiment, a pilot signal 515 is a known symbol sent in a fixed pilot power 507 in one tone, and the null pilot signal 513 is a tone with a transmission power of zero. These pilot tones 515 and null pilot tones 513 can jump over time, which means that from an OFDM symbol to the text, the position they occupy can vary. For extended periods of time, the transmissions of the pilot signal are periodic due to the repetition of the jump sequences. In Figure 5, four pilot signal tones 515 and one null pilot signal tone 513 are shown. The tone locations of the pilot signals 515 and the null pilot signals 513 are known for both the BS 1200 and the WT 1300. Figure 5 also shows twenty-six data tones 511, with the corresponding transmission power level 509. Figure 5 illustrates that the tone transmission power level of the pilot signal 515 is significantly higher than the transmission power level. of 509 data tones, allowing wireless terminals to easily recognize pilot tones. In general, the transmission power of the data tone 509 may not necessarily be the same in all data tones as shown in Figure 5, although the level 509 may vary from one data tone to another. In the situation of a wireless deployment deployed with omni-directional antennas, the modality specifies a single null pilot signal known as the null cell pilot signal. It is assumed that a pilot signal tone is transmitted at the power P, and a tone carrying the data traffic at the power Q is transmitted, as indicated in figure 5. When viewing the signal received from the pilot signal , the WT 1300 has the ability to measure the SNR, which we will refer to as SNR (P). The goal is for the base station 1200 to be able to obtain an estimate of SNR (Q), which is the SNR as can be seen by the wireless terminal 1300 corresponding to the transmission of the base station of the data in the power Q, which may be different from P. Knowledge of the received SNR is important since it determines the combination of code ranges and modulation constellations that can be supported. For a specific target block error range (for example, the probability that the transmission of a single code word is incorrect) and for each coding and constellation range of modulation, it is possible to define a minimum SNR that the received SNR must exceed in order that the probability of a unsuccessful transmission than the specific target range (for example, block error rate of 1%). From this point of view, it is desirable that the BS 1200 has the ability to accurately estimate the SNR (Q) in order to solve the transmission power Q which will produce an S? R exceeding the minimum S? R for the code range and the desired modulation constellation. The relationship between SNR (Q) and Q depends on the noise dependent on the signal. For purposes of description, it is assumed that the signal-dependent noise is proportional to the transmission power and uses the noise characteristic line 305, 405 as shown in Figures 3 and 4 to characterize the dependence of the total noise as a function of the received signal strength. The principle can be extended in a similar way to other situations. Let denote the gain of the channel, so that when the BS transmits in the power P, the power received by the wireless terminal is aP. Let N denote the independent noise of the signal, and? P represent the noise dependent on the signal, where? is the proportionality factor to the transmission power P. Later when the SNR is measured in pilot tones, the WT 1300 measures a SNR of SMO (P) = ____ £ _, 'N +? P where P is the constant transmission power of the pilot signals and N is the noise independent of the signal observed by the WT 1300. We call this "SNR1" to indicate that it treats the signal-dependent interference as a single entity. When using the null pilot signal, it is possible for WT 1300 to separately measure the noise independent of the N signal, since there is no power transmitted by the BS 1200 at this null tone. By comparing this noise independent of the signal N with the received power aP of the pilot signal BS, it is possible to estimate an S? R that is free of the noise dependent on the signal. Let us represent this P proportion by NK0. { r) N, en on (eg name "SNRO" indicates that it considers a noise not dependent on the signal.) Then the relationship between SNR1 (P) and SNRO (P) is provided by: - + £. SNRl. { p) SNR0. { P) a ' For simplicity of notation, we define £ -__. = •.

When comparing with the characteristic noise line shown in figures 3 and 4, it can be seen that SNRO (P) corresponds to the intercept of the line's x-axis, while SRR1 is equivalent to the slope of the line. Then as a function of SNRO (P) and SRR1, we can write: SNR JP) SNRI (P) = SRR1-SNR0 (P) +1 In one modality, SNRO (P) and SRR1 measurements are reported through WT 1300 to BS 1200. From these reports, BS 1200 can compute SNP2 (P). The graph 600 of Figure 6 illustrates the relationship between SNR1 (P) on the vertical axis 601 and the SNRO (P) on the horizontal axis 603, where the SNRs are plotted in dB. Three curves are illustrated by lines 605, 607, and 609 that represent SRR1 = 0, SRR1 = 0. 5 and SRR1 = 1, respectively. The case of SRR1 -0 (line 605) corresponds to the situation where the noise is independent of the signal, so that SNR1 (P) = SNR0 (P). The case of SRR1 = (line 609) corresponds to the case where the noise dependent on the signal is equal to the signal, so that it is never possible that SNR1 (P) exceeds 0 dB. From the information received from the WT 1300, the BS 1200 can later compute the S? R received as a function of the transmission power Q for the data traffic. The S? R received by the WT 1300 will include noise dependent on the signal, and takes the form of SNRl (ß) = c¿Q N +? Q Investing and carrying out substitutions is provided: Therefore as a function of the SNRO (P) values and SRR1 reported by the WT 1300, it is possible to anticipate the S? R as observed by the WT 1300 for any transmission power Q. These leads illustrate that using the null pilot signal, the WT 1300 can determine and transmit statistics to the BS 1200 which enable the BS 1200 to anticipate the SNR as a function of the transmission power in the presence of signal-dependent noise that is proportional to the transmission power. It should be noted that instead of sending SNRO (P) and SRR1, there are other groups of equivalent reports that the WT 1300 can send to BS 1200, which falls within the scope of the present invention. The methods and apparatus of the present invention are particularly useful in a multiple sector cell. In wireless cellular systems, base stations 1200 are often deployed in a configuration where each cell is divided into multiple sectors, as shown in Figure 11. For a sectorized environment, interference between sectors 1106. 1108, 1110 has a significant impact on the received SNR. In addition to the independent part of the signal, the noise also includes parts dependent on the signal, each of which is proportional to the signal power of other sectors of the same cell 1104. The noise characteristics in this case are more complex that what is shown in figure 3, because in this sectorized situation, the total noise includes two or more components dependent on the signal instead of one. However, the total noise can still be characterized by a straight line, which is now defined in a larger dimensional space. This characteristic line of noise can be described, for example through interceptions and slopes. The intercept is a function of the independent noise part of the signal and each slot corresponds to the proportionality of the noise part dependent on the signal with respect to a particular signal power. However, in certain scenarios the description of the noise characteristic line can be simplified. For example, in an example sectorization method, wherein each of the sectors of a cell can use all or almost all of the transmission resource, for example, the frequency band, to transmit in each of the sectors. The total power transmitted from each sector is usually fixed or known, although different WTs 1300 may receive a different fraction thereof. Since the insulation between the sectors is not perfect, the signal transmitted in a sector becomes noise (interference) for the other sectors. Furthermore, if each of the sectors 1106, 1108, 1110 is restricted to transmit in an identical, proportional or quasi-proportional signal power in a given degree of freedom, the interference of the other sectors with a WT 1300 in a given sector 1106 , 1108, 1110 seems like a noise dependent on the signal or a self-noise. This is the case whereby the interference of other sectors increases with the signal power, so that the noise characteristic line is similar to that shown in Figure 3. According to the present invention, the BS 1200 transmits signals such as the null cell pilot signal "which allows the WT 1300 to evaluate the intercept of the noise characteristic line with all the noise independent of the signal, and, as an example, the programming between the sectors 1106, 1108, 1110 can be coordinated so that the WTs 1300 at the 1150, 1152, 1154 limit of the sectors do not receive any interference (or receive reduced interference) from other sectors In accordance with the present invention, the BS 1200 transmits signals such as "sector null pilot signal" that allows the WT 1300 to evaluate the slope of the noise characteristic line that takes into account only the noise dependent on the signal coming from the sectoral subgroup In accordance with the present invention, the WT 1300 subsequently reports the SNR independent of the signal and these different slopes, or some equivalent information group, back to the BS 1200 on a reverse link. Figure 7 shows a diagram 700 for signaling in an embodiment of the present invention, in the case of a cellular wireless system sectorized using the Orthogonal Frequency Division Modulation (OFDM). A BS 1200 with three sectors 701, 703, 705 should be considered in which the same conveyor frequency is again used in all sectors 701, 703, 705. The pilot signal power level corresponding to sectors 701, 703, 705 is indicated by reference numbers 709, 713 and 717, respectively. The power levels of the data signal are indicated by reference numbers 711, 715, 719 for each of the first to the third sectors, respectively. The situation of other sector numbers will be described later. The three sectors 1106, 1108, 1110 of the base station 1200 should be allowed to be represented by SO 701, S1703, and S2 705 as shown in FIG. 7. FIG. 7 shows a tone assignment for the transmission of downlink in a given OFDM symbol 707, including an example of the placement of data tones, eg, example data tones 728, pilot signal tones, e.g. pilot signal tones 728, pilot tones null, by example, null example pilot signal tone 721, through the three sectors. Since it is assumed that each of the sectors shares the same frequency band, the corresponding tones between the sectors will interfere with each other. It should be noted that the position and order of the tones are shown for illustration purposes only, and may vary in different implementations. According to the present invention, the downlink signal one or more null pilot cell signals, which are null tones that are shared by each of the sectors 701, 703, 705. In a null pilot signal of cell 729, In addition, the downlink signal includes one or more nulls of sector 721, 723, 725, in which the transmission power is zero only in the case of a transmission power of zero in each of the sectors 701, 703, 705. a subgroup of sectors 701, 703, 705. In the same tone as the null pilot signal of the sector, it is desirable to have a pilot tone or a data tone whose transmission power is fixed and known for the WT 1300 in the other sectors. For example, the pilot signal null 723 of sector SI 703, has the pilot tone 731 of the corresponding SO sector 701 and the pilot signal tone 737 of the corresponding sector S2 705. In a modality shown in figure 7, there are four pilot signals, a null sector pilot signal and a pilot zero signal of cell in each sector 701, 703, 705. For example, sector SO 701 has four pilots 731, 733, 735, 737, a null pilot signal of sector 721 and a null pilot signal of cell 729. These pilot signals are distributed from so that each sector has two unique pilot signals, and then share a pilot signal with each of the other two sectors. For example, sector SO 701 has unique pilot signals 735, 727; the pilot signal 731 shares a tone frequency with the pilot signal 737 of the S2 705 sector; the pilot signal 733 shares a tone frequency with the pilot signal 739 of the sector SI 703. Furthermore, the null pilot signal of the sector of one sector coincides with the tones of the pilot signal in the other sectors. For example, for null tone 725 in sector S2 705, a pilot signal 733, 739 is transmitted in the same tone in sectors SO 701 and SI 703, respectively. The locations of the pilot signal tones, the null tones of the cell and the null sector tones are known for both the BS 1200 and the WT 1300. Pilot signals change their positions, or "jump" over time. several reasons, such as frequency diversity. Figure 8 provides an example of a pitch jump of the pilot signals, null pilot cell signals and null pilot signals of the sector. The graph 800 of Figure 8 traces the frequency on the vertical axis 801 vs. time on horizontal axis 803. Each small vertical subdivision 805 corresponds to a tone, wherein each small horizontal subdivision 807 corresponds to an OFDM symbol time. Each pilot tone 809 is represented by a small box with vertical shading. Each null pilot signal of sector 811 is represented by a small box with a horizontal line shading. Each null pilot cell signal 813 is represented by a small box with a shading traced transversely. In one embodiment, the tones of the pilot signal essentially jump after a modular linear hop pattern. According to the present invention, the null sector tones jump after the same modular linear pattern as the pilot signal jumps with the same dependent value. In addition, in one embodiment of the present invention, the tones of the cell null pilot signal also jump after the same modular linear pattern as the pilot signal jumps with the same dependent value. In one embodiment, the data tones essentially jump after a permuted modular linear hop pattern. In another embodiment of the present invention, the null pilot cell signals jump after the same permuted modular linear pattern that the data jumps. In this mode, when a null pilot cell signal tone is collided with a pilot signal tone, either the transmission of the pilot signal tone in each of the sectors is suspended and the tone of the pilot signal is erased in a effective, or the transmission of the pilot signal tone continues in at least part of the sectors and the tone of the pilot cell null signal becomes effectively unusable. It is assumed that the WT 1300 has a link established with the sector SO of the base station 1200, and that the gain of the SO channel for the WT 1300 is provided by a. Similarly, it is assumed that the channel gain from SI to WT 1300 is provided by ß, and from S2 to WT 1300 it is provided by?. Finally to complete, it is assumed that the noise dependent on the signal in the link from SO to WT 1300 includes auto-noise that is proportional to the transmission power with a channel gain of d. It is assumed that the transmission power for the data tones in the three sectors is provided by Q0, Q1 and Q2, respectively. Subsequently, the SNR received from the link from SO to WT 1300 is provided by SNRS0 (ßO, Ql, Q2) = - ^.

For the rest of the present description, it will be assumed that the interference due to the other sectors (ßQl and Q Q2) is much more significant than the noise dependent on the signal coming from the same dQO sector, so for simplicity, this term will be omitted in the subsequent description. The WT 1300 must provide a set of parameters to the base station, so you have enough information to anticipate the SNR received for the downlink data transmission from SO to WT 1300. To obtain that information, signal tones can be used pilot null. Using a null cell pilot signal, in which the transmission in each of the sectors is 0, it is possible to measure the noise independent of the signal. When comparing this with the strength received from the OS pilot signal, the following SNR is provided: SM? 0 (P) = - Subsequently, the tones of the null pilot signal of the sector can be, and in various modalities, are used to measure the SNR in the situation where one of the surrounding sectors is not transmitting. In particular, for the SW sector, the tone of the pilot signal corresponding to a tone of the pilot signal null of the sector in S2 should be considered. Subsequently, the measurement of the SNR based on this pilot signal in the SO sector, will provide the value SNRlβ. { p) = < ßP + N ' Where the interference sector is SI (with the path gain ß). Similarly, when measuring the SNR in the pilot signal tone which is a null sector tone in SI, the interference sector is sector S2 (with the path gain?), And the resulting SNR is provided by SNR ¥ (P) = ^ jP + N The slopes of the noise characteristic line in these two cases are ß v and ~ Y * »respectively. Subsequently, if the SNR is measured directly using the tones of the pilot signal that do not correspond to the null points of the sector in the other sectors, then this SNR measure takes into account the interference from the other two sectors. This measure is called SNR2, since it includes the interference of the two sectors. AP SNR2 (P) = ßP + pP + N The slope of the noise characteristic line in this case is ß + r Cv •. By defining the following SRR as appropriate slope values of the noise characteristic lines, it is possible to relate SNRlß (P), SNR1Y (P) and SNR2 (P) with SNRO (P) , _ ß +? SRR2 = a SRRlß = -.1 to SRRÍr =: a The SRRs themselves can be computerized in terms of the SNRs, as indicated below: 1 1 SRR2 = SNR2. { P) SNR0 (P) 1 1 SRRlβ = SNRlβ. { p) SNR ?. { P) 1 1 SRRlr = SNRV. { P) SNR ?. { P) It should be noted that SRR2 can be found as the sum of SRRlβ and SRRl ^. Then the SNRs can be written in terms of SNRO (P) and SRRs: SNR2 (P) = SNROJP) l + SRR2-SNR ?. { P) SNRi (P) = SNR ° W,?; l + SRRlr - $ NR? (p) SNRI * (P) = ^ 5Í_1_; l + SRRlß -SNR ?. { P) If the WT 1300 reports a sufficient group of these statistics (eg, SNRO (P), SRRlβ, SRR1Y, SRR2) to the base station 1200, the base station 1200 can anticipate the SNR received by the WT 1300 based on the powers of transmission QO, Ql, and Q2.In general, the SNR as seen by the WT 1300 for a data transmission with power QO, with interference of the sectors SI and S2 with the powers Ql and Q2, is determined in terms of the measurements made in the pilot signal tone with the transmission power P as: QO SNRS0 (Q0, Ql, Q2) = ßQl + lQ2 + N In Figure 9, diagram 900 shows three situations of an example WT in sector SO. Cell 901 includes three sectors SO 903, SI 905 and S2 907. Figure 9 shows a WT 909 near the boundary with SI sector 905, where WT 909 receives significant downlink interference from sector SI 905. The cell 921 which includes three sectors SO 923, SI 929 and S2 927 shows a WT 929 at the center of sector SO 923, far from the limits of the sector. The 941 cell that includes the three sectors SO 943, SI 945 and S2 947 shows a WT 949 near the limit with sector S2 941, where WT 949 receives significant downlink interference from sector S2 947. In one embodiment of the present invention, for each of these three situations , the WT sends to the BS 1200 a subgroup of the measured statistics, in order to reduce the amount of information transported in the reverse link, for example uplink. In the situation shown in Figure 9 with respect to cell 901, it is assumed that WT 909 in sector SO 903 receives significant interference from sector SI 905. Then a coordinated programmer 1225 of the base station can disconnect data transmissions in the sector SI 905 that interfere with the transmissions of the sector SO 903 to the WT 909. Meanwhile, the transmission in the sector S2 907 is coordinated so that it has the same or almost the same transmission power Q as in the sector SO. Subsequently, the SNR observed by WT 909 will be provided by: ^ w ^ SNROJP) SRRlr -SNR0 (p) + Q case in which it is sufficient to report SNRO (P) and SRR1Y. Subsequently, for the situation shown in Figure 9 with respect to the cell 921, in which the WT 929 is not close to a sector boundary, it is possible to transmit in most or all sectors without causing too much interference in the WT 929. In this case, it is assumed that the programmer of the base station 1225 makes the simplification assumption that each of the three sectors must transmit data with the same power Q. Subsequently the SNR observed by the WT 929 for a transmission of sector SO 923 is provided by: aQ SNR5Q (Q, Q, Q) = ßQ + jQ + N SNROJP) SRR2-SNR0. { P) + - In this case, it is sufficient to report SNRO (P) and SRR2. Subsequently, for the situation shown in Figure 9 with respect to cell 941, WT 949 is located near the sector boundary with sector S2 947. Since WT 949 receives significant interference from sector S2 947, a coordinated programmer 1225 for the 1200 base station, it can disconnect the corresponding data transmissions in sector S2 947. Meanwhile, it is assumed that the transmission for the SI 945 sector is programmed with the same transmission power Q as in the SO 943 sector. SNR observed by WT 949 will be provided by SM._0 (ß, ß,?) = AQ ßQ + N SNRü (p) SRRlβ -SNR0. { P) + - case in which it is sufficient to report SNRO (P) and SRRlß. Therefore, if the BS 1200 restricts the transmission powers so that they are equal to some Q value or equal to O, then in each of the three possible configurations, only a subset of information needs to be transmitted from the WT 1300 to the BS 1200. In particular, in one embodiment, the wireless terminal 1300 makes a decision to see which of the situations (for example as shown in Figure 9 cell 901, Figure 9 Cell 921 and Figure 9 Cell 941) the WT 1300 is currently there. This information can be transmitted by the WT 1300 to the BS 1200 as a two-bit Sector Limit Indicator. The sector limit indicator indicates the position information of the wireless terminal in relation to a sector boundary. The first bit could indicate if the WT 1300 is in a limit, so that it is necessary to disconnect the transmission in the surrounding sector. The second bit can indicate which of the two sectors causes more interference. Possible indicators of sector boundaries of two bits are described in the first column of table 1 shown below. The second column of table 1 indicates the noise contribution information. The third column describes the control action as it will be taken by the BS 1200 in response to receipt of the corresponding sector limit indicator. The fourth column describes the two channel quality indicator values reported due to the corresponding reported sector limit indicator described in the same row.

In this way, since the WT 1300 identifies the 1200 base station whose configuration is the preferred one, the WT 1300 needs only to report SNRO (P) and one of the three SRRs. Next, a multiple-sector cell with an arbitrary number of sectors will be described. In another embodiment of the present invention, for the situation where there is an arbitrary number of sectors, the sectors are divided into three types of sectors, which will be marked as SO, SI and S2. This classification in types of sector is done in such a way that two adjacent sectors will not have the same type. It is assumed that for two non-adjacent sectors, the interference effect is considered small enough not to be significant, so that the main cause of interference comes from adjacent sectors of different types. Therefore, it is possible to treat this situation in an analogous way for the case of the three-sector cell, since the source of primary interference in each sector comes from its two surrounding sectors. Figure 10 includes a diagram 1000 showing the sector types of the example cells 1001, 1021 and 1041 with 3, 4 and 5 sectors, respectively. The cell 1001 includes a first sector 1003 of the OS type sector, a first sector 1005 of the SI type sector and a first sector 1007 of the sector type S2. The 1021 cell includes a first sector 1023 of the SO sector type, a first sector 1025 of the SI sector type, a first sector 1027 of the sector type S2 and a second sector 1029 of the sector type S2. The cell 1041 includes a first sector 1043 of the SO sector type, a first sector 1045 of the SI sector type, a first sector 1047 of the sector type S2, a second sector 1049 of the SW sector type and a second sector 1051 of the sector type YES Table 2 below provides an example of a plan for different numbers of sectors, where the order of the list of sector types corresponds to the order proceeding (for example, clockwise) around the sector. TABLE 2 Using the previous sector type scheme, the scheme comprising the null pilot cell signals and the null sector pilot signals for the case of three sectors, can be used for an arbitrary number of sectors. Although described within the context of an OFDM system, the methods and apparatus of the present invention are applicable to a wide range of communication systems, including many of the non-OFDMs. In addition, some features are applicable to non-cellular systems. In various embodiments, the nodes described herein are implemented using one or more modules to carry out the steps corresponding to one or more methods of the present invention, for example, signal processing, message generation and / or transmission steps. Therefore, in some embodiments several features of the present invention are implemented using modules. These modules can be implemented using software, hardware or a combination of software and hardware. Many of the methods and steps of the methods described above can be implemented using machine executable instructions, such as software, included in a machine-readable medium such as a memory device, for example RAM, floppy disk, etc. to control a machine, for example a general-purpose computer with or without additional hardware, to implement all or parts of the methods described above, for example, in one or more nodes. Accordingly, among other things, the present invention is directed to a machine-readable medium that includes machine executable instructions that cause a machine, eg, a processor and associated hardware, to perform one or more of the steps of the method (s) described above. Those skilled in the art will appreciate numerous additional variations in the methods and apparatus of the present invention described above, by virtue of the detailed description of the previous invention. Said variations will be considered within the scope of the present invention. The methods and apparatus of the present invention may be, and in various embodiments are used with CDMA, orthogonal frequency division multiplexing (OFDM), and / or various other types of communication techniques that may be used to provide wireless communication links between access nodes and mobile nodes. In some embodiments the access nodes are implemented in the form of base stations that establish communication links with mobile nodes using OFDM and / or CDMA. In various modalities, the mobile nodes are implemented in the form of computers for personal notes, personal data assistants (PDAs), or other portable devices that include reception / transmission circuits and logic and / or routines, to implement the methods of the present invention. Figure 14 illustrates the steps of an example method 1400 for transmitting tones of the pilot signal in multiple sectors of a cell in a synchronized manner according to the present invention. The method starts at the start node 1402 and proceeds to step 1404, where the time counter of the current symbol is started, for example, 1. The symbols are transmitted in the example system in bases per symbol with a symbol time. which is the time used to transmit a symbol together with a cyclic prefix which is usually a copy of a part of the transmitted symbol which is added for redundancy, to protect against multipath interference and minor symbol transmission timing errors. The operation proceeds from step 1404 to step 1406, wherein the transmitter is controlled to transmit symbols of the pilot signal that will be transmitted at the current symbol time in each sector in a synchronized manner using the same tones in each sector according to a pre-selected pilot signal transmission sequence, for example, pilot signal tone jump sequence, using pre-selected transmission power levels in each sector of the cell. Although the pilot signals are transmitted in each sector of a cell in parallel, the power level transmitted in a tone can be a certain preselected level or zero, in the case of a null tone. Although the transmission times of the pilot signals in each sector are generally synchronized, slight timing compensations may occur between the sectors. Therefore, each sector can actually use a different period of time to transmit symbols. However, the symbol times in each sector are sufficiently synchronized so that there is a substantial overlap in the times of the symbol used to transmit the symbols in each sector. Normally, the substantial overlap is such that the start times of the symbol transmission are synchronized to be within at least one period of time corresponding to the time used to transmit the cyclic prefix sometimes referred to as the cyclic prefix duration. Therefore, there is usually a substantial overlap in symbol times of different sectors, even if there is no perfect overlap in symbol times. Said tones are used for pilot signal tones during a particular symbol time which is determined from the information of the jump sequence tone of the pilot signal 1234 included in the tone information 1238, while the power that will be used in a given tone in each sector of the cell, is determined from the power level information 1236. Once the tones of the pilot signal are transmitted for the current symbol time in step 1406 the operation proceeds to the step 1408 wherein the current symbol time count is incremented by 1. Subsequently in step 1410 a check is made to see if the current symbol time has reached a maximum symbol time. If the current symbol time is equal to the maximum, the current symbol time is readjusted to one, so that the jump sequence of the pilot signal can begin to repeat at step 1406. Periodic transmission of pilot signal tones it continues to repeat according to the tone jump sequence of the pilot signal implemented until transmission of the base station is stopped or until some other event causes the transmission process of the pilot signal to be interrupted. Referring now to Figures 15 to 17, several tone transmissions of the example pilot signal are shown together with the transmit power information of the pilot signal.

In accordance with the present invention, the tones of the pilot signal are transmitted using the same tones in multiple sectors of a cell at the same time or substantially at the same time. In various embodiments of the present invention, symbol transmission times are synchronized in various sectors of the cell. Assuming perfect synchronization, there could be a total overlap in terms of the time between the tones of the pilot signal transmitted in the various sectors and one cell at any given time. Unfortunately, as noted above, precise timing may not be possible for a variety of reasons related to the complexity of transmission synchronization between different amplifiers and the operation of antennas at high frequencies. However, in synchronized sector implementations, a substantial amount of symbol time overlap exists between the sectors. Therefore, pilot transmissions can be achieved with a substantial overlap that makes signal measurements that assume a total overlap during at least a part of each of the possible times of transmission of sector symbols. As mentioned above, in the synchronized mode of the present invention, the difference between the start times of symbol transmission between the various sectors of a cell is usually less than the duration of the cyclic prefix which is normally included with the symbols transmitted. For purposes of description, it will be assumed that there is a total synchronization with signals, for example, symbols, which are being transmitted at the same time in a synchronized manner in each sector of a multiple sector cell. However, the above description makes it clear that such precise timing does not normally occur and is not required to carry out the present invention. Therefore, the transmission in each sector corresponds to a different symbol time which can be slightly compensated from the symbol time of the adjacent sector. According to the present invention, although the tones of the pilot signal are transmitted in each sector of a cell in the same group of tones in a synchronized manner, the power of the tones of the pilot signal in different sectors of a cell are controlled to allow different signal measurements that facilitate, in a particular sector, the determination of the noise contribution of others, for example, adjacent sectors, as well as background noise. To facilitate multiple different signal measurements, multiple tones of the pilot signal can be used during a single symbol transmission time.

As an alternative, a pilot signal may be used per symbol time in which the pilot signal is assigned different power levels during, for example, different symbol times, successive. In such a case, the measurements of the pilot signal made during different symbol times can be used to produce the two different channel quality indicator values which are returned to the base station according to the present invention. Figure 15 is a graph 1500 showing a two-sector pilot signal tone transmission sequence implemented in an exemplary embodiment of the present invention. As will be described later, the sequence shown in Figure 15 can be extended to systems with sectors N, where N is an arbitrary number greater than 1. The sequence shown in Figure 15 is implemented for a cell that includes two sectors, sector A and sector B. The times of the symbols in each sector can be slightly compensated, although substantially overlapping and therefore will be described as the same time of symbols although they really are two different times of symbols in many cases. The first column 1502 entitled time, refers to the symbol time in which a tone is transmitted assuming a perfect synchronization between the sectors. In one embodiment, when the same tone is used at each symbol time for the purposes of the pilot signal, each symbol time from 1 to 4 corresponds to a different current symbol time. The second column 1504 entitled TONE, describes the tones, for example, frequency in each of the pilot signals that are transmitted. Each row corresponds to a tone. The different rows may correspond to the same tones or different tones depending on the particular implementation. For example, in cases where the symbol times from the first to the fourth is the same current symbol time, then the first tones from the first to the fourth described in column 1504 will be different since each pilot signal requires a tone. However, in cases where the first to fourth symbol times in column 1502 correspond to different times of current symbols, the tones described in column 1504 may be the same or different. As described above, each row 1512, 1514, 1516, and 1518 corresponds to the transmission of a tone in each of the sectors of cells A and B, for example, a tone that is used to transmit a pilot signal. The transmission power levels in each of the sectors may be different or the same. In each case, the tone of the pilot signal transmitted at any point in time is transmitted with a preselected transmission power. Therefore, the transmission power and the tone in which a pilot signal is transmitted will be known for both the base station 1200 and the wireless terminals 1300, since this information is stored in both devices, and both know the time of current symbol from the timing information available in the cell. In Figure 15, the third column 1506 describes the transmission power level of the pilot signal, of the pilot signal transmitted in sector A, using the tone to which the particular row corresponds. Similarly, fourth column 1508 describes the transmit power level of the pilot signal of the pilot signal transmitted in sector B, using the tone to which the particular row corresponds. Each column 1510 of column 150 is included for purposes of explaining a three-sector modality, although it is not used in the two-sector implementation that is being described with respect to Figure 15. Each rectangle in column 1506 and 1508 represents a step to transmit a pilot signal in the sector indicated in the general symbol time indicated in column 1502, using the tone indicated in column 1504. In practice, the tones are transmitted in slightly different symbol times in each of the sectors A and B, for example, first and second symbol times corresponding substantially to the symbol time described in column 1502. Al is used to indicate a non-zero pilot signal having a first preselected transmission power, while the zero is used to indicate the transmission of a null tone, for example, a pilot signal transmitted with zero power. Row 1502 shows that at symbol time 1, using tone 1, a pilot signal is transmitted in sector A, while a NULA pilot signal is transmitted in sector B. This makes it possible to measure the contribution of inter- -sector in sector B originated by the transmission of sector A in the same tone. It also allows sector A to make accurate measurements of the attenuation in sector A, without the presence of interference due to the transmission of sector B. Row 1514 corresponds to symbol time 2, where tone 2 is used to transmit a NULL tone in sector A, and a pilot signal in sector B. This allows sector A to determine the amount of signal interference due to the transmission of sector B therein. Row 1516 corresponding to symbol time 3, where tone 3 is used to transmit a NULA pilot signal in both sectors A and B, making possible general measurements with background noise in tone 3. Row 1518 corresponds to symbol time 4, where it is used tone 4 in both sectors A and B to transmit pilot signals 1. In this case, each sector can measure the effect of having a signal transmitted with the same power level of zero in each of sectors A and B at the same time. Normally pilot signals are transmitted according to both the first and second rows 1512, 1514 of Figure 15, and at least one of rows 1516 and 1518, in order to provide a wireless terminal that performs sufficient signal measurements which are required as input for two different functions used to generate the first and second channel quality indicator values that are fed back to the base station 1200 according to a feature of the present invention. Figure 16 illustrates an exemplary pilot signal tone transmission sequence of a three sector system. As in the example of Figure 15, the first column 1602 corresponds to the symbol transmission time, the second column 1604 corresponds to the tone, while the columns 1606, 1608, and 1610 indicate the transmissions of the pilot signal at each one of the three sectors A, B, and C of a cell, respectively. Therefore, as in the example of Figure 15, each rectangle of the column 1606, 1608, and 1610 corresponding to one of the rows of the first to the fifth 1612, 1614, 1616, 1618, 1620, represents the step of transmitting a pilot signal in the indicated tone in the indicated sector. Although the tones used in each row are the same in each sector, as described above, when each of the symbol times corresponds to the same current symbol time, each of the first to fifth tones will be different. However, when each of the first to the fifth symbol times are different from the first to the fifth tones they may be the same or different. It should be noted that in the implementation of Figure 16, at least one pilot signal is transmitted for each sector, a null pilot signal being transmitted at the same tone in an attached sector. It should also be noted that the use in row 1620 of what has been described as a cell null facilitates measurements of background noise. Figure 17 is a graph 1700 showing a three-sector implementation similar to that of Figure 16, with the pilot signals transmitted in each sector being described more generally in terms of power levels. The transmission of the fifteen pilot signals from PI to P15 is shown in the embodiment of FIG. 17, each pilot signal being transmitted at a different symbol time in the case where each row corresponds to a different transmission symbol period. . In the case where each of the described signals will be transmitted at the same symbol time, three different symbols are shown, the transmission time of each sector being slightly different, although corresponding substantially with the same symbol time used in the other sectors. As in the examples of FIGS. 15 and 16, the pilot signals of each of the rows 1712, 1714, 1716, 1718, 1720 are transmitted using the same tone although different rows may correspond to different tones. Although it is shown as being transmitted in five different symbol times as described in the first column 1702, when the variations in transmission times of the sector are taken into account, each rectangle described in the Sector header may actually correspond to a different symbol time where the symbol times of each row overlap, and are identical in the case of precise synchronization. The power level of each of the fifteen pilot signals from Pl to P15, they are represented in parentheses, for example, the transmission power for Pl is Pl. Although in some cases, as in the example of Figure 16, two different power levels are supported, multiple known power levels can be supported. The last row 1720 of FIG. 17 represents the transmission of a NULA pilot signal using the tone 5 in each of sectors A, B and C according to the power level of these pilot signals, which is zero in each case. Figure 18 illustrates a graph 1750 showing the transmission of signals in ten different tones during a single period of time of symbol transmission. In the implementation of Figure 18, the 0 is used to represent a NULA pilot signal, while the 1 is used to represent a pilot signal at a single level of known non-zero transmission power which is usually greater than the level of power in which the data is transmitted. The D is used in the graph 1750 to illustrate the transmission of data in one of the sectors A, B and C. The data signal D, is normally transmitted in the tone at a power level lower than the level of the pilot signal 1, and therefore may not cause significant interference with the pilot signal in the surrounding sector. The data is normally transmitted in each of the sectors in additional tones not shown in Figure 18 during the illustrated symbol time. In the OFDM mode of the present invention, in a given sector said additional data tones do not interfere with the tones of the pilot signal, since they are orthogonal to the tones used to transmit the pilot signals. Figure 19 illustrates a method 1800 for operating a wireless terminal to process pilot signals received from a base station 1200, which were transmitted in accordance with the present invention. The received pilot signals can be pilot signals that were transmitted with different known transmission power levels, allowing the receiving apparatus to perform various signal measurements and useful computations to determine various noise contributions, for example, background noise as well as interference inter-sector The method 1800 starts at the start node 1802 and proceeds along two processing paths beginning with steps 1804 and 1808, respectively. The two processing paths can be implemented in parallel, for example, in the case where multiple pilot signals with different levels of transmission power are transmitted during a single symbol time, or in series, for example, in the case where Pilot signals are transmitted sequentially using the same tone although different power levels during different symbol transmission times. In step 1804, the wireless terminal 1300 measures at least one of an amplitude of a phase of a first pilot signal that was transmitted with transmission power Pl to produce a first measured signal value. The first signal value measured subsequently is used in step 1806. In step 1806, a first channel quality indicator value is generated from the first measured signal value according to a first function, fl, which uses minus the first signal value measured as an input. The first channel quality indicator value generated by the fl function can be, for example, an SNR value or a signal power vapor, which corresponds to the first received pilot signal. Function fl can use other signal measurements and / or other information as input, in addition to the first measured signal value when, the first channel quality indicator value is generated. The operation proceeds from step 1806 to step 1812. In step 1808, which can be performed in parallel with step 1804 in some embodiments, wireless terminal 1300 measures at least one of an amplitude of a phase of a second signal pilot which was transmitted with the P2 transmission power, where P2 is different from Pl. The measurement produces a second measured signal value which is subsequently used in step 1810. In step 1810, a second channel quality indicator value is generated from the second measured signal value according to a second function, f2 , which uses the second signal value measured as an input. The second function is different from the first function and uses at least the second signal value measured as an input, although you can also use other signal measures as inputs. In some embodiments, the second channel quality indicator value generated by the second function is an SNR value corresponding to the second pilot signal, while in other modalities it is a signal power value, for example, an indicator of received signal power, which corresponds to the second pilot signal. The operation proceeds from step 1810 to step 1812. In step 1812, the wireless terminal 1300 determines the location of the wireless terminal relative to one or more sector boundaries from the measured signal values and / or other limit location indicator value described above. When using the relative limit location and / or some other information generated in step 1812, in step 1814 the wireless terminal 1300 generates a limit location indicator value 1814, for example, having a value corresponding to one of the values shown in column 1 of table 2. With the first and second channel quality values of steps 1806 and 1810, the indicator value of the boundary location from step 1814, the operation proceeds to transmission step 1816, in where the generated information is transmitted back to the base station 1200. Step 1816 comprises the transmission of the first and second channel quality indicator values and the limit location indicator value, for example, as part of one or more messages. Two alternative processing paths are shown as a single processing path in any particular implementation. The first processing path that begins with sub-step 1820 and ends in 1826, represents the case where different information is included in a single message. The second processing path that begins at step 1830 and ends at step 1840 corresponds to the case where different messages are used to transmit each of the various values. Messages within this context will be interpreted widely and will include signals that carry the particular values that will be communicated. In step 1820, the first channel quality indicator value is incorporated into a first message. Subsequently, in step 1822 the second channel quality indicator value is incorporated in the first message. Subsequently, in step 1824 the limit location indicator value is incorporated in the first message. The first message is then communicated to the base station 1200 in step 1816, for example, by transmitting the first message through a wireless communication link. This is done in various modalities using one or more time slots of a control channel used to report channel quality information and / or some other feedback information from the wireless terminals to the base station 1200. As a result of the dedication of the time slot to the wireless terminal using it to report the channel quality and other information, other terminals or wireless devices in the sector will not use the time slot. Therefore, through the use of dedicated time slots, transmission conflicts are avoided. In addition, because the channel is dedicated to communicating particular control information, the values can be generated and transmitted in the time slots without having to send headers or other information indicating what the transmitted values mean. This is, the base station 1200 knows the values transmitted in the control channel used that have a certain pre-selected format and represent, for example, first and second channel quality indicator values followed by a limit location indicator value of 2 bits. Therefore, the amount of air space, for example, airspace of the header that is used to transmit said messages and / or values can be minimized. With the transmission of the generated values that have been completed in step 1822, the operation returns steps 1804 and 1808, where signal measurements are made in the new pilot signals with the feedback process that continues repeating over time. In step 1830, which corresponds to the alternative value transmission path shown in step 1816, the first channel quality indicator value is incorporated in a first message, for example, a signal which is subsequently transmitted to the station base in step 1832. Subsequently, in step 1834 the second channel quality indicator value is incorporated in a second message, for example, signal, which is transmitted in step 1836. The limit location indicator value is incorporated. in step 1838 in a third message, which is subsequently transmitted to the base station 1200 in step 1840. As in the case of the combined message transmitted in step 1826, the individual messages transmitted in steps 1832, 1836 and 1840 they can be transmitted using dedicated segments of a dedicated control channel to communicate the feedback information. The operation proceeds from step 1840 to steps 1804 and 1808 with processing the generation of the channel feedback information and reporting the information to the base station 1200 which is repeated over time. Figure 20 shows a flow chart 1900 illustrating a method for operating the base station (BS) 1200 in accordance with the present invention, for example, transmitting the pilot tones and receiving and processing feedback information to determine the power level in which the data signals are transmitted. The method begins with step 1902 wherein the base station 1200 is energized and remains in operation. In step 1904, the transmitter of the base station 1204 coupled to a multiple sector antenna 1205, transmits pilot signals in each sector, for example, SO 1106, SI 1108, S2 1110 of a multiple sector cell, for example, 1104 at the same time in a synchronized manner using predetermined power levels and tones so that the transmission of the pilot signal tones in each of the sectors 1106, 1108, 1110 of the cell 1104 uses the same set of tones and is transmitted substantially at the same time in each of the sectors 1106, 1108, 1110. The transmission of the pilot signal tones in step 1904 is carried out under the direction of the pilot signal generation and transmission control routine 1230 that uses the tone power level information of the pilot signal 1236 and the tone information 1238. The operation proceeds to step 1906 wherein the BS 1200 receives messages from at least one wireless (WT) terminal 130 0, which include, for example, a group of channel quality indicator values, for example, first and second channel quality indicator values, and position information of the sector boundary. The messages are received under the address of the received signal processing routine 1260 included in the base station 1200. In step 1908, the base station, under the direction of the channel quality extraction value indicator module 1262 extracts at least two different channel quality indicator values 1250, for example, from a single message or from multiple messages received from a wireless terminal 1300. In some embodiments, each channel quality indicator value is a separate message. In other modalities, the multiple channel quality indicator values are included in a single message from a WT 1300. Subsequently, in step 1910, the base station 1200, under the control of a position information extraction module 1264, extracts the information of location of received messages, for example, limit position indicator value, indicating the position of a wireless terminal 1300 relative to a limit in a multiple sector cell. This location information may have been transmitted by the WT 1300 in a separate message or may have been included in a message that includes channel quality indicator values. This location information can identify if the WT 1300 is close to a sector boundary, and identify which sector boundary, for example, identifies the adjacent sector from which a higher level of interference dependent on the transmission power is being received. The sector limit information extracted from received messages is stored in a limit position information of sector 1252 in BS 1200. Proceeding to step 1912, base station 1200, under the direction of the power calculation routine of transmission 1226 calculates from at least the first and second channel quality indicator values 1250, an amount of transmit power that is required to achieve a desired signal-to-noise ratio in the wireless terminal 1300, from which the first and second channel quality indicator values 1250. In step 1914, the base station programmer module 1225 operates to make programming decisions for the 1300 wireless terminals. In sub-step 1916, the 1225 base station programmer makes decisions of the WT 1300 based on the determined SNR, for example, the BS 1200 program segments for the WT 1300 in channels with transmit power levels which will result in an SNR received from the WT 1300 that exceeds a minimum acceptable level for the range of data and a coding scheme used. In sub-step 1918, scheduler 1225 of the BS 1200 makes decisions of the WT 1300 based on a sector limit position information 1252, for example, of a WT 1300 identified as being close to a sector boundary, the 1200 base station allocates channel segments to the WT 1300, with corresponding channel segments in the adjacent sector that have no transmission power. Proceeding to step 1920, the transmitter 1205 of the BS 1200 transmits the signal, which may include, for example, user data 1244 that has been encoded by the encoder 1214, under the direction of the signaling routine 1228 at a scheduled time for the WT 1300, using a given transmission power from at least two 1250 channel quality indicator values that were received.

The operation comes from step 1920 back to step 1904 and the method is repeated. The base station 1200 will repeat the transmission of the pilot signals in a synchronized fashion in each sector of a multiple sector cell in step 1904, on a regular basis. However, different wireless terminals 1300 can send messages that include a group of channel quality indicator values 1250 and sector limit position information 1252 at different times and / or different ranges depending on factors such as the operating status of the wireless terminal, for example, on, hold, hold. The present invention is directed, inter alia, to a machine-readable medium, such as a memory, compact discs, etc., which include executable instructions on the machine, for example, software modules or commands, for controlling a processor or other apparatus for carrying out the processing according to one or more of the various steps of the method of the present invention. Various features of the apparatus methods of the present invention can be used in a wide range of communication systems, including, but not limited to, OFDM, CDMA communication systems, and other types of communication systems.

Claims

Novelty of the Invention Having described the present invention, it is considered as a novelty of the invention and, therefore, the content of the following is claimed as property: CLAIMS 1. A method that reports the quality of the channel to be used by a wireless terminal, wherein the method comprises: measuring at least one of an amplitude and a phase of a first pilot signal corresponding to a first tone of pilot signal for produce a first measured signal value; generating a first channel quality indicator value from the first measured signal value according to a first function using at least the first signal value measured as an input; transmit the first channel quality indicator value; measuring at least one of an amplitude of a phase of a second pilot signal corresponding to a second tone of the pilot signal, to produce a second measured signal value, the second pilot signal having a different transmit power to that of the first signal pilot; generating a second channel quality indicator value from the second signal value measured according to a second function, which uses at least the second signal value measured as an input; transmit the second channel quality indicator value. The method according to claim 1, characterized in that one of the first and second pilot signals is a NULL signal transmitted with zero power. The method according to claim 1, characterized in that the generation of a first channel quality indicator value of the first signal value measured according to a first function includes: estimating the power included in at least one of the first and second pilot signals received. The method according to claim 3, characterized in that the generation of a second channel quality indicator value from the second signal measurement value according to a second function includes: estimating the received power included in at least the second pilot signal received. The method according to claim 3, characterized in that the generation of a second channel quality indicator value from the second measured signal value according to a second function further includes: estimating the signal to noise ratio of the second pilot signal received. The method according to claim 1, characterized in that the generation of the first channel quality indicator value from the first measured signal value according to the first function includes: estimating the signal to noise ratio of the first signal pilot received. The method according to claim 6, characterized in that the generation of a second channel quality indicator value from the second measured signal value according to the second function includes: estimating the signal to noise ratio of the second pilot signal received. The method according to claim 1, characterized in that the first and second pilot tones are received during different periods of time without overlap. The method according to claim 8, characterized in that the first and second pilot signal tones correspond to the same frequency. The method according to claim 1, characterized in that the first and second pilot signal tones are received during the same time period, and the first and second pilot signal tones correspond to different frequencies. The method according to claim 1, characterized in that the transmission of the first quality indicator value includes: incorporating the first channel quality indicator value in a first message; and transmit the first message through a wireless communication link. The method according to claim 1, characterized in that the transmission of the second channel quality indicator value includes: incorporating the second channel quality indicator value in the first message, - transmitting the second channel quality indicator value with the first value in the first message through the wireless communication link. The method according to claim 11, characterized in that it further comprises: carrying out repeatedly the steps of: measuring a first pilot signal to produce a first measured signal value; generate a first channel quality indicator value; incorporate the first channel quality indicator value in a first message; transmit the first message through a wireless communication link; measure a second pilot signal; generate a second channel quality indicator value; incorporate the second channel quality indicator value in a second message which is different from the first message; and transmit the second message through the wireless communication link. 14. The method according to the claim 13, characterized in that it further comprises: periodically repeating the steps of transmitting the first channel quality indicator value and the second channel quality indicator value to transmit the corresponding values generated by the repeated execution of the measurement and generation steps, the first and second channel quality values being transmitted in a form interspersed with time. 15. The method of compliance with the claim 14, characterized in that the interleaved form includes alternating the transmission of the first and second messages. The method according to claim 13, characterized in that the first and second messages are transmitted using segments of the communication channel dedicated to carry the channel quality indicator values, not carrying the messages, explicit message types that indicate the messages that report the quality values of the channel. The method according to claim 16, characterized in that the messages are transmitted during preselected dedicated time slots, dedicated for use by the wireless terminal, excluding the dedication of the time slots dedicated to other wireless terminals using the time slots. dedicated 18. The method according to claim 1, characterized in that the wireless terminal is located in a first sector of a sectorized cell, in which each sector uses the same group of tones, the step of measuring at least one of an amplitude of a phase of a first pilot signal to produce a first measured signal value, wherein the step includes: carrying out the first pilot signal measurement during a period of time in which a sector located adjacent to the first sector transmits another pilot signal in the same tone as the first pilot signal, although using a different preselected transmission power from the selected transmission power used to transmit the first pilot signal. 19. The method according to the claim 18, characterized in that the other pilot signal is a NULL pilot signal and wherein the different preselected transmission power used to transmit the other pilot signal during the time period is zero. 20. The method of compliance with the claim 19, characterized in that the second step, of measuring at least one of an amplitude and a phase of a second pilot signal to produce a second measured signal value, includes: carrying out the second pilot signal measurement for a period of time during wherein a sector located adjacent to the first sector transmits an additional pilot signal at the same tone as the second pilot signal, using the same preselected transmission power as the selected transmission power used to transmit the second pilot signal. 21. The method according to the claim 20, characterized in that the first and second measurements of the pilot signal are carried out at the same time. 22. The method according to claim 21, characterized in that it further comprises: measuring, at the same time, the received power in a third tone in which signals are not transmitted during the same time, the same time being a symbol period used to transmit a symbol. The method according to claim 18, characterized in that it further comprises: determining the relative position of the wireless terminal in at least two sectors adjacent to the sector in which the wireless terminal is located, based on the first and second measurements of the wireless terminal. signal; transmit the position information indicating a position relative to a sector boundary for a base station. The method according to claim 23, characterized in that it further comprises: selecting the channel information that will be transmitted to the base station, as a function of the determined relative position of a sector boundary. The method according to claim 24, characterized in that the different channel condition information is transmitted when the wireless terminal is close to a first sector boundary, rather than when it is near a second sector boundary. 26. The method according to claim 18, characterized in that the first channel quality indicator value is a function of a channel gain ratio of an interference sector and the sector in which the wireless terminal is located. 27. The method according to claim 18, characterized in that the second signal measurement is performed during a period of time wherein each of the sectors transmits a NULL in the second tone; wherein the second channel quality indicator value is a measure of the noise in the second tone during NULA transmission, through each of the sectors of the cell in the second tone. The method according to claim 18, characterized in that the method is further directed to use channel quality information to control the transmit power in a sector of a cell, wherein the method comprises: operating a base station to receive the first and second channel quality indicator values; and operating the base station to calculate from the first and second channel quality indicator values, an amount of transmit power that is required to achieve a desired signal-to-noise ratio in the wireless terminal, the calculation requiring at least two different channel quality indicator values to determine the amount of transmission power. 29. The method according to claim 28, characterized in that it further comprises: periodically repeating the step of operating the base station to calculate the amount of transmission power using a different group of first and second channel quality indicators received. of the wireless terminal, each of the different groups of first and second channel quality indicator values corresponding to a different symbol time during which the first and second measurements of the pilot signal were performed. 30. A wireless terminal, wherein the wireless terminal includes: a receiver for receiving pilot signals; measurement means for measuring at least one of an amplitude and a phase of a first pilot signal to produce a first measured signal value and at least one of an amplitude and a phase of a second pilot signal to produce a second measured signal value; means for generating the channel quality indicator value for generating a first channel quality indicator value from the first measured signal value according to a first function, which uses at least the first signal value measured as an input and generates a second channel quality indicator value from the second measured signal value according to a second function which uses at least the second signal value measured as an input; and a transmitter for transmitting the first and second channel quality indicator values. The wireless terminal according to claim 30, characterized in that the means for generating the channel quality indicator value includes software instructions for controlling a processing apparatus for: estimating the received power included in at least one of the first and second pilot signals received. The wireless terminal according to claim 31, characterized in that the means for generating the pilot channel indicator value further include additional software instructions for controlling the processing apparatus for: estimating the received power included in at least the second pilot signal received. The wireless terminal according to claim 31, characterized in that the means for generating the channel quality indicator value further include additional software instructions for controlling the processing apparatus to: estimate the signal to noise ratio of the second signal pilot received. 34. The wireless terminal according to claim 31, characterized in that the means for transmitting include: a message generation module for generating a first message including the first channel quality indicator value. 35. The wireless terminal according to claim 34, characterized in that the message generation module includes the second channel quality indicator value in the first message. 36. The wireless terminal according to claim 34, characterized in that the message generation modules include machine executable instructions for controlling a machine to generate a second message that includes the second channel quality indicator value. 37. The wireless terminal according to claim 34, characterized in that it further comprises: means for determining the position of the wireless terminal relative to a sector boundary from the received signals. 38. The wireless terminal according to claim 37, characterized in that the message generation module includes position information in the first message. 39. A base station comprising: a receiver for receiving at least two channel quality indicator values from a wireless terminal; means for determining at least two different channel quality indicator values, a transmission power required to achieve a desired signal-to-noise ratio in the wireless terminal. 40. The base station according to claim 39, characterized in that at least two different channel quality indicator values correspond to different power signal measurements made by the wireless terminal at the same time, the transmission power being determined as a function of at least two channel quality indicator values. 41. The base station according to claim 40, characterized in that it further comprises: means for transmitting a signal to the wireless terminal using a given transmission power of at least two channel quality indicator values. 42. The base station according to claim 41, characterized in that it further comprises: means for extracting at least two different channel quality values from a single message received from the wireless terminal. 43. The base station according to claim 41, characterized in that it further comprises: means for extracting at least two different channel quality values from two separate messages received from the wireless terminal. 44. The base station according to claim 40, characterized in that it further comprises: means for receiving channel quality indicator information indicating the position of the wireless terminal in relation to a second limit included in a multiple sector cell. 45. The base station according to claim 40, characterized in that it further comprises: a multiple sector transmission antenna for transmitting pilot signals in a plurality of sectors of a cell at the same time; a transmitter coupled to the multiple sector antenna to transmit pilot signals in each sector in a synchronized manner, so that the transmission of the tones of the pilot signal in all sectors of the cell uses the same group of tones and is transmitted substantially at the same time in each of the sectors, the wireless terminal being located in one of said multiple sectors. R E S U N A Methods and sequences for the transmission of pilot signals are described, for use in a multi-sector cell. The pilot signals in different sectors are transmitted at different known power levels. In adjacent sectors, a pilot signal is transmitted, while a non-pilot signal is transmitted in the attached sector. This represents the transmission of a NULA pilot signal. A cell NULA is also supported, where the NULAS pilot signals are transmitted in each sector of a cell at the same time. Multiple measurements of the pilot signal are made. Based on the corresponding measurements, at least two channel quality indicator values of at least two pilot signals of different power levels are generated. The two values are again transmitted to the base station, which uses both values to determine the transmission power required to achieve a desired SNR in the wireless terminal. The wireless terminal also reports information indicating its location to a sector boundary.