MXPA06004229A - Carrier search methods and apparatus - Google Patents

Abstract

Transmitting signals, e.g., high power narrow band signals on a periodic basis to facilitate detection of a frequency band and/or carrier signal to be used for communication with a basestation are described. The detected frequency band may be a downlink frequency band. The uplink frequency band to be used can be determined from a know frequency relationship between the detected downlink carrier and a corresponding uplink carrier or by monitoring the detected downlink frequency band for information indicating the uplink frequency band/carrier to be used. Carrier search methods involving searching for the narrowband high power signals used to provide carrier information and/or to indicate the frequency band to be monitored are described. Power detection methods can be used to detect the high power signals avoiding the need for symbol timing synchronization and/or channel estimation with regard to detection of the signals used to locate the frequency band to be used.

Description

APPARATUS AND METHODS OF CARRIER SEARCH FIELD OF THE INVENTION The present invention relates to communication systems and, more particularly, to methods and apparatus for facilitating and / or carrying out a carrier search.

BACKGROUND Several service providers have been acquiring frequency spectrum in several frequency bands based on the availability of the wireless communication spectrum in several, relatively limited, geographic regions. A goal of at least some of its service providers from creating a relatively large network by providing services using the available frequency bands that can be acquired from region to region. The Multichannel Multi-Point Distribution System (MMDS) Band is a title sometimes used to describe an unconventional band formed by a plurality of different frequency bands in different geographic regions. The MMDS allows opportunities for service providers that hold rights to different frequency spectra in different geographical places. The MMDS band is not conventional since a service provider can be assigned different frequency bands in different geographical regions, for example, cities or states. It is also not conventional that the carrier frequency to be used may be different in different geographical areas and may be determined by the particular service provider in the region. In this way, there is not a single primary carrier, which is known over a wide area, for example, the whole country, to which a mobile can initially be tuned after entering a service area to obtain information and assignment or carrier and / or additional band. Service providers can deploy the system in different carriers in different areas, depending on the availability of spectrum. The wireless terminals, which can operate in any number of different areas, have to search and find the available carrier after entering an area to obtain services using the MMDS band. In addition, in FDD (Frequency Division Duplex) systems, the pairing of the downlink and uplink carrier frequencies may not be fixed over a wide area, eg different carriers used for signaling for the link descending may be associated with different carriers used for uplink signaling in different geographic areas. It should be appreciated from the above discussion that the use of different frequency bands and / or carriers in different places can greatly complicate the task of confronting a wireless terminal with respect to which frequency band and / or frequency (or frequencies) carrier it must be used in a particular geographic region. Accordingly, there is a need for an apparatus and methods that allow a wireless terminal to quickly and efficiently search and find the carrier frequency or frequencies and / or the frequency band to be used for communications purposes in a particular geographic region. SUMMARY The present invention is directed to methods and apparatus that can be used to facilitate the detection of one or more carriers and / or a frequency band to be used by a wireless terminal, for example, when communicating with a base station or other device in or more geographic regions. Various embodiments of the present invention use signaling by radio beacon to facilitate detection and selection of the carriers and / or frequency band to be used. The method and apparatus of the present invention can be used in a system, which includes cells with one or multiple sectors per cell. In accordance with the present invention, different base stations may use different carrier frequencies for signaling on the uplink and / or downlink. A frequency band used to communicate information, for example, user data and / or control signals, is associated with each carrier frequency. Each frequency band can be divided into a number of different tones for communication purposes with the different tones corresponding to different frequencies. In accordance with the invention, each base station in a system periodically transmits one or more high power signals, referred to herein as beacon signals, on a periodic basis to facilitate the detection of a frequency band and / or carrier signal to be used. for communication with the base station that transmits the beacon signals. In some systems using the invention, transmitters of the base station in different sectors and / or cells periodically transmit a high power signal, sometimes called a beacon signal in its own frequency band of the downlink. Beacon signals are signals which usually include one, but sometimes some, narrow signal components (in terms of frequency), for example, signal tones, which are transmitted at a relatively high power compared to other signals as user data signals. In some embodiments each of the beacon signals includes one or more signal components, where each component of the signal corresponds to a different tone, a component of the beacon signal with some modalities includes a signal energy per tone which is 10, 20, 30 or more times the signal energy per average tone of signal tones used to transmit user and / or control data signals different from those of beacon. In the case of a single-tone beacon signal as the frequency of the beacon signal is easily determined from the frequency of the single high-power tone constituting the beacon signal. In the case where more than one high power tone has been used as a beacon signal, for the purposes of the present application, the frequency of the beacon signal is a frequency determined according to a predetermined frequency definition.

This definition is set for a given implementation and therefore is predictable in terms of how the beacon signal will be interpreted. In many embodiments, the frequency of a beacon signal with multiple tones is predefined as one of the tones in the beacon signal, for example, the frequency of the lowest or highest tone that is included in the beacon signal. In other embodiments, the frequency of beacon signals is defined based on the frequency of at least one high-power tone in the beacon signal but can be determined as the value that is a combination of the frequency of multiple tones of High power. Although the manner in which the frequency of a beacon signal may be determined may vary, the use of a consistent definition of the frequency of each beacon signal of a particular type in a particular application allows proper interpretation of the signal information. of radio beacon. Since carrier radiobeacon signals are usually implemented as single-tone beacon signals, the concepts of the present invention will be described primarily in the context of one-tone beacon signal implementations. However, it should be appreciated that the methods and the apparatus of the present invention are not limited to those exemplary implementations. Different types of beacon signals can be transmitted to carry different types of information related to the base station. The information appears to be conveyed by the frequency of the tone or tones used to transmit a beacon signal and / or the frequency of multiple beacons when the beacon signals are detected for a period of time. The pattern of beacons that are transmitted can be set and known by the wireless terminals in the system that can use this information to interpret the meaning of the beacon signals received. For example, carrier radiobeacons can be transmitted at a fixed frequency distance from the boundary edge of a frequency band of the downlink. At least one component of the signal, for example, the tone, one of the beacon signals used to carry carrier information is often placed in a fixed pitch location relative to the highest or lowest tone used by the transmitter for communications through the downlink. In some modalities, this unique tone used to transport Carrier information is the highest power tone of any of the beacon signals transmitted. Nevertheless, this is not a mandatory requirement. Although the tone of the beacon signal used to transmit the carrier information is normally fixed in terms of frequency, in some embodiments the tone used for the beacon beacon may be missing, for example, changed, according to a known jump pattern. by the transmitting base station as by the wireless terminals in the system. Carrier beacon signals are often, but not always implemented as single-tone signals that are usually transmitted in a fixed pitch location within the frequency band to be used for communications purposes downlink. However, other types of beacons, for example, cell-identifying beacons and / or sector identifiers can, and frequently, jump within the frequency band used for communications purposes downlink according to a known jump sequence. . Carrier radiobeacons, in many modes, are transmitted at a lower speed (for example, they are less frequent) than other types of beacon signals, such as cell or sector-identifying radio beacon signals.

The systems implementing the radio beacon transmission methods of the present invention typically include multiple cells, for example, at least one first and one second cell. The first and second cells will often use different carriers and in this way different frequency bands depending on the geographical region in which they are located. Although both cells will transmit beacon signals according to the invention, the transmission timing of the signals need not be aligned in time and as in most cases, the cells will not be synchronized with respect to the transmission timing of the signals. symbols. In one of those exemplary embodiments, a sector transmitter of the first base station in the first cell will transmit using a first frequency band for a first period of time, for example, an ultrainterval, which will include many smaller intervals, for example , a second period of time. In each of the intervals of the second period of time, for example, radiobeacon intervals, at least one beacon signal is transmitted in the first frequency band. The type of beacon signal may vary depending on the place within the ultra-interval in which it is transmitted. During the longer time interval large, for example, the ultrainterval, at least one carrier radio beacon is transmitted and, in the exemplary embodiment, multiple radio beacon signals identifying cells and sector identifiers are transmitted. In the exemplary embodiment, the second cell includes a second transmitter of the base station transmitting using a second frequency band which is different from the first frequency band during a third period of time, for example, an ultra-interval occurring in the second cell. The third period of time includes many smaller intervals, for example, the fourth period of time. In each of the intervals of the fourth period of time, for example, the radiobeacon intervals in the second cell, at least one beacon signal is transmitted. During the longest time interval, for example, the ultra-interval in the second cell, at least one carrier beacon is transmitted within the frequency band of the downlink used in the second cell, in the exemplary mode, multiple beacon signals are transmitted. cell identifiers and sector identifiers in the frequency band of the downlink that is used. Since different frequency bands are used in the first and second cells, the carrier radio beacons they will be transmitted at different frequencies, for example, using localized tones at a fixed deviation in terms of the frequency of one of the frequency band ends used. In some particular embodiments, in order to facilitate the information of the carrier radiobeacons, for example, the carrier beacon tones, they are transmitted to the lowest or highest tone used to transmit a beacon signal with a sector or cell. When this optional feature is used, combined with the optional feature of not skipping the carrier radiobeacon signal while skipping the other beacon signals used in the cell, the carrier beacon becomes relatively easy to identify. In some modalities, the carrier radio beacon is the only fixed-tone beacon that is used in the cell with all other types of beacon being jumped. However, this is a limitation of all modalities. In some embodiments, the carrier frequency and the corresponding communications band to be used for uplink signaling have a fixed relationship, eg, have a known frequency difference, of the carrier frequency of the downlink that can be detected from agree with the invention. Where there is such a fixed relationship, wireless terminals can store the information of the frequency relationship. Using the stored information and determined information of the beacon signals thus received about the carrier frequency of the downlink, the wireless terminals can determine the carrier frequency and / or carrier band of the uplink once the frequency and / or carrier band of the Downlink has been identified. In other embodiments, after determining the frequency band of the downlink to be used, the wireless terminal checks the downlink frequency band for the broadcast information, indicating which bearer and / or frequency band of the uplink will use. This information can be communicated as a deviation of the downlink bearer with an explicit message indicating the carrier frequency and / or width of the uplink frequency band to be used in communication with the base station that transmitted the bearer beacon signal detected. Several bearer detection techniques that take advantage of radio beacon transmission methods are novel, and the fact that they will be transmitted in a downlink in a way predictable that allows a receiver to determine the location and / or width of a frequency band to be used are described in detail in the following description. The detection techniques involve searching a frequency band for a beacon signal, adjusting the frequency band that is being examined after a detection of a beacon signal and continuing to verify the second beacon signal. On the basis of the frequency of one or both of the radiobeacon signals detected, the carrier frequency and / or frequency band used for signaling communications by the downlink is determined. Notably, the use of radio beacon signals allows a receiver to detect, using energy detection techniques applied to received beacon signals, which carrier frequency should be used and the location of a communications band corresponding to the carrier to be used. , without a wireless terminal that has to achieve symbol timing or carrier frequency synchronization with a base station transmitting the beacon signals and having already generated a channel estimate of the channel through which the beacon signals were transmitted to the wireless terminal. Of this Thus, the frequency band to be used for downlink signaling can be determined in many cases, before the OFDM symbols that require symbol timing to decode can be decoded and interpreted. The methods and apparatus are well suited for use in OFDM communication systems as well as other types of communication systems. In OFDM systems, multiple symbols modulated by a transmitter in parallel are often transmitted during each period of time of transmission of OFDM symbols. In some embodiments, each beacon interval includes more than 10, for example, 16 or more, transmission time periods of OFDM symbols. In some modalities, each ultrainterval includes multiple intervals of beacon. In some implementations each ultrainterval includes a very large number of symbol transmission time periods, for example, more than 1,000 and, in some embodiments, more than 10,000 periods of symbol transmission time. The number of tones and the bandwidth used for uplink and downlink signaling may be different in different system implementations and within different cells or sectors of a system. In a particular exemplary embodiment the number of tones used for downlink signaling exceeds 100 tones. The separation between the frequency bands used pays for the uplink signaling and the downlink can be as small as the frequency separation between the tones used for downlink signaling, but in some embodiments the frequency bands of the downlink and the uplink are separated by many tones. In those embodiments, knowledge about the location of the uplink bearer to be used in relation to the downlink bearer may be important in determining the appropriate uplink bearer to be used. As discussed above, depending on the particular mode, the information of the uplink bearer in relation to the particular downlink carrier or frequency band can be pre-stored where the relationship is fixed through a system or region or can be obtained from the signals transmitted on the downlink. Although different frequency bands are used for signaling by uplink and downlink in many modes, it is possible that the signaling bands of the link The uplink and the downlink overlap, for example, with the tones in the uplink and downlink bands being interleaved according to a known pattern. Numerous variations of the methods and apparatus of the present invention are possible. Although many of the features of the invention have been discussed, features, benefits and additional exemplary embodiments of the methods and apparatus of the present invention are provided in the following detailed description.

BRIEF DESCRIPTION OF THE FIGURES Figure 1 is a drawing of exemplary beacon signaling that can be used within a service band, in accordance with the present invention. Figure 2 is a drawing illustrating another exemplary embodiment of beacon signaling, in accordance with the present invention, and the signaling of Figure 2 is shown on a time frequency grid. Figure 3 shows an exemplary bearer deployment situation for deploying different service bands in an unconventional band in different areas.

Figure 4 is a drawing showing an exemplary carrier search method, in accordance with the present invention. Figure 5 is a flow chart of an exemplary method for locating carrier frequencies, in accordance with the present invention. Figure 6 is a drawing of an exemplary communication system implemented in accordance with the present invention. Figure 7 is a drawing of an exemplary base station implemented in accordance with the present invention using the methods of the present invention. Figure 8 is a drawing of an exemplary wireless terminal (end node), for example mobile node, implemented in accordance with the present invention and using the methods of the present invention. Figure 9 is a flow chart of an exemplary method for operating a base station for transmitting beacon signals in accordance with the present invention. Figure 10A and Figure 10B is a flow diagram of an exemplary method for operating a wireless (WT) terminal to detect a carrier signal transmitted by a base station that transmits beacon signals on a periodic basis, in accordance with the present invention .

Figure 11 shows the steps of an exemplary base station signaling method of the invention, where the beacon signals by a plurality of different base stations.

DETAILED DESCRIPTION OF THE INVENTION The present invention is directed to methods and apparatus that can be used to facilitate the detection of one or more carriers and / or a frequency band to be used for a wireless terminal, for example, when communicating with a base station or other device in one or more geographic regions. Various embodiments of the present invention use beacon signaling to facilitate the detection and selection of carriers and / or the frequency band to be used. In the context of the present application, the beacons are signals that include one or more narrow band signals of relatively high power transmitted at the same time. Each narrowband signal in a beacon signal may correspond to a single tone. The beacon signals are usually transmitted using more power than is used to transmit data signals, for example, 2, 5, 20, 100 or even more times as much power as the higher power data signals.

The methods and apparatus of the present invention can be applied to a wide variety of communication systems but are in particular very suitable for use in frequency division multiplexed systems such as orthogonal frequency division multiplexed systems. The method and apparatus of the present invention will be described in the exemplary context of an orthogonal frequency division multiplexing (OFDM) system that uses beacon signals to support a method of relatively low complexity, efficient and / or to find carriers according to the invention. As noted above, the beacon signal is a high frequency signal, in a usual manner, considerably more powerful than any individual pilot or data signal having the same bandwidth as the beacon signal. Indeed, radio beacon signals are often many times more powerful than a pilot or standard data tone making them relatively easy to detect. Since radio beacons usually occupy very little bandwidth, for example, a single tone, the frequency of a beacon signal (tone) is also relatively easy to determine. In the case of radiobeaten signals with multiple tones, in some embodiments of the invention the frequency of one of the tones of the beacon signal, for example, the tone of the beacon signal having the highest or lowest frequency in the beacon signal, is used as the frequency of the beacon signal, and , in some cases, this tone that is used to determine the frequency of the beacon signal is transmitted with more power than the other tones in the beacon signal. However, other methods may be used to determine the frequency of transmission of the beacon signal as long as the method is consistent with the implementation of the methods of the invention. The beacon signals usually have a short duration, occupying an OFDM symbol transmission time period in an exemplary OFDM mode. Beacon signals are generally transmitted relatively infrequently compared to normal signaling and data signaling. Figure 1 shows a drawing 100 illustrating the exemplary beacon signaling that can be used within a service band. A service band is the bandwidth from which the system of interest is displayed. For example, some bands of the service are 1.25 MHz while others are 5 MHz. The horizontal axis 102 represents frequency. The distance 104 represents a service band of 1.25 MHz. A carrier frequency is represented as fc 106, and is frequently, but not necessarily, centered within the service band 104. The beacon signals are transmitted from a base station over a transmission channel. Downlink emission, for example, each beacon signal is of a single tone in a single OFDM symbol with all or most of the transmit power of the sector concentrated over the beacon signal tone. The beacon signals are transmitted periodically, for example, once every 90 msec. Different types of beacon signals, for example, inclined beacons, sectorial beacons and beacon beacons can be transmitted at different times. Note that the slope or slope is a cell identifier. In some modalities, the location, in the frequency domain, of the tilt and sector markers may change (jump) over time, while the location of the carrier radiobeacon, in the frequency domain, is at a fixed location in relationship to the carrier. Figure 1 shows a first inclination or slope beacon 108 occurring at time TI, a first sector beacon 110 that occurs at time T2 and a second incline or slope beacon 112 occurring at time T3, a second sector beacon 114 occurring at time T4, on a carrier beacon 116 that occurs at time T5. Note that the frequency of inclination or slope radiobeacons 108, 112 and sector beacons 110, 114 are not fixed and change with time, while the location of carrier beacon 116 is fixed at fc_, and there is a fixed deviation 118 with respect to the carrier frequency fc 106. In some embodiments, the carrier-type radiobeacons 116 are transmitted less frequently in time than the radiobeacons of the dependent and sector type, for example, a carrier beacon 106 is transmitted every 16 intervals of time. radio beacon Figure 2 provides a 2000 illustration for another exemplary similar modality of beacon signaling; The illustration of Figure 2 shows a time-frequency grid. In Figure 2, the horizontal axis 2004 represents the time and the vertical axis 2002 represents the frequencies or tones of the downlink. Each division of the vertical axis represents a 2008 tone, while each division of the horizontal axis represents an OFDM 2010 symbol. Each small square in this Figure represents a single tone in an OFDM symbol that is sometimes referred to as a tone symbol. The 2006 grid shows 10 2008 tones over 30 OFDM symbols 2010 or 300 tone symbols. Each tone symbol can be used to carry a beacon signal, normal / control data or be left unused. The legend 2016 identifies carrier beacon tones 2018 by shading the horizontal line, inclined beacon tones or 2020 slope by the shading of the diagonal line that slides down from left to right, beacon tones of sector 2022 by shading of the diagonal line that slides up from left to right, and normal data / control tones 2024 by the crossed out shading. The small boxes in the 2006 grid that were left unhidden represent tones during the OFDM symbols that were left unused. In the example of Figure 2, a beacon signal is a special OFDM symbol in which almost all of the downlink transmit power is concentrated on a single tone, although a power close to zero is used on all other tones. In one embodiment, the beacon signals are periodically transmitted so that the time interval between any two successive beacon signals is a constant, which is called a beacon interval. Thus, in a beacon interval there is a beacon signal. Figure 2 shows an exemplary radiobeacon interval 2012 that includes four symbols Successive OFDM; an OFDM symbol is used by the beacon signal and three OFDM symbols are used to carry the data / control signaling. Figure 2 further shows that the locations of the frequency tones of different beacon signals are different. In the example of Figure 2, the location of the bearer beacon tone remains fixed while the pitch location of the beacon and sectorial beacon tones jump over time; the beacon beacon tone is at a lower frequency than any of the beacon or sectorial beacon tones. In Figure 2, the carrier radio beacon is transmitted less frequently than the incline sector beacons; A carrier radio beacon is transmitted for every two inclined or slope beacons and two sector beacons. The beacon tone pattern is repeated over a larger time interval, referred to as ultraintervals. In the example of Figure 2, a carrier radiobeacon occurs by ultra-interval and the ultrainterval includes 5 intervals of beacon. Figure 2 is presented for the purpose of illustrating various concepts and features of the present invention. An exemplary embodiment, in accordance with the present invention, may include: 113 shades of downlink, a beacon signal by one of 904 OFDM symbols, a beacon interval of 90 msec duration, an ultrainterval spanning 16 beacon intervals or 1.44 sec, a beacon beacon in a fixed pitch location by ultrainterval, and radiobalizas of slope / sector by ultraintervalo. Some exemplary embodiments may include 25 ranges of radiobeacon by ultrainterval. Note that within a service band, in some modes, the frequency tone of a carrier radiobeacon is lower than that of any slope beacon or sector. As will be clarified later, this arrangement of tones helps to look for carrier radiobeacon signals. It can be seen that the same benefit can be obtained if the frequency tone of a carrier radiobeacon is greater than that of any slope or inclined beacon or sector. Figure 3 is a drawing 700 showing an exemplary carrier deployment situation of the deployment of different service bands in an unconventional band in different areas. The horizontal axis 701 represents the frequency. In Figure 3, the unconventional band 702 has a bandwidth of 50 MHz in total. In an FDD system, the 50 MHz are distributed to include two bands (704, 706), a band 704 used for the downlink and the other band 706 used for the uplink. The unconventional band 702 also includes a separation band 708 between the downlink and uplink bands (704, 706). In some embodiments, the unconventional band 702 is allocated in a downlink and uplink band and does not include a separation band. Figure 3 also shows that a service provider has a service band of 1.25 Hz in both the downlink and the uplink. However, the downlink and uplink service bands are different in different geographical areas and the separation between the bearers of the downlink and the uplink also varies. In one area, the service provider has the downlink band 710 and the uplink band 712 with bearer separation 714, while in another area the service provider has the downlink band 716 and the uplink band 718 with bearer spacing 720. Since the wireless terminal does not know the location of the downlink and uplink service bands, it has to carry out a bearer search procedure. He Bearer search procedure includes two general steps. In the first step, the wireless terminal quickly explores possible service bands to detect the existence of beacon signals by verifying the energy received in the downlink signal. After a beacon signal has been detected, in the second step, the wireless terminal then searches for a beacon beacon signal to identify the location of the bearer. At any step, to detect beacon signals, the wireless terminal sets a search frequency and verifies a downlink signal of a search band centered on the search frequency. In one embodiment, the search band has the same bandwidth as the service band, for example, 1.25 MHz. The advantage is that the wireless terminal can use the same physical device, such as RF filters, for the search procedure of the carrier and for normal service. Note that for a given search frequency carrier, the corresponding search band may not overlap, partially overlap, or completely overlap with the service band. If the search band does not overlap with the service band, then the wireless terminal will not detect no beacon signal at any time interval of a beacon interval. If the search band completely overlaps the service band, then the wireless terminal will detect a beacon signal at any time interval of a beacon interval. If the search band partially overlaps with the service band, then the wireless terminal may or may not detect any beacon signal at any time interval of a beacon interval. Figure 4 is a drawing 800 showing an exemplary carrier search method, in accordance with the present invention. Figure 4 includes a graph of the frequency on the vertical axis 802 against time on the horizontal axis 804. Figure 4 also includes a downlink band 806. The downlink band 806 includes a minimum frequency 807 and a plurality of service bands, including a service band 808 for the area in which the WT is currently located. The service band 808 includes beacon signals transmitted periodically, including carrier and radiotrack beacons of slope / sector; the radiobeacons of the slope / sector type being transmitted more frequently than the carrier-type radiobeacons. Legend 801 includes a beacon type exemplary carrier 810 illustrated by a small box with shading of the horizontal line and a radio beacon type of slope / sector example 802 and illustrated by a small square by shading the diagonal line. This shaded representation of legend 801 is used in the service beacons 808. The carrier beacon 810 is the lowest frequency beacon of the beacon types in the service band 808. Figure 4 also includes a band of search 814 which includes a bandwidth of the search band 816. The bandwidth of the search band 816 is the same size as the bandwidth of the service band. The search band 814, in terms of the searched frequencies, moves during the search process and is represented as the search band 814a, 814b, 814c at different times. The size of step 818 is the amount of search band 814 that moves if a beacon is not found during the first verification time interval. The adjustment of the search frequency 820 is the amount of the search band 814 that moves on the basis of a beacon detected during a first verification time interval. The adjustment amount 820 may vary as a function of the location of the beacon detected within the band of search 814. Drawing 800 includes the first successive verification time intervals (822, 824); undetected beacons during the first verification time interval 822, and a beacon 826 is detected during the second first verification time interval 824. After the second first verification interval 824 there is a second verification time interval 828, longer in duration than the first verification interval and including two successive detected beacon beacons 830, 832. The exemplary carrier search method will now be described. The wireless terminal begins the first step by setting the search frequency so that the search band 814 covers the lower end of the downlink band 806 as represented by 814a. The wireless terminal checks the downlink signal of the search band 814 for a first verification time interval 822, which is in the order of a small number of beacon intervals. For example, the first verification time interval is set slightly longer than the beacon interval, eg, the duration of two beacon intervals. For example, in the case where the beacon interval is 90 msec, the first verification interval can be set at 180 msec. If the wireless terminal does not detect any beacon signal within the first verification time interval 822, the wireless terminal concludes that the search band 814a does not overlap with the service band 808. The wireless terminal then increases the search frequency in a step size 818. The step size 818 should not exceed the size of the bandwidth 816 of the search band 814. In the example shown, the size of the step 818 is equal to the size 816 of the search band 814, for example, 1.25 MHz. In one embodiment, the step size is slightly smaller than the search band size, for example, 1.00 MHz or half the size of the search band. After increasing the search frequency by the step size 818, the wireless terminal sets the new search frequency and the corresponding new search band 814b. Similarly, the wireless terminal verifies the downlink signal of the new search band 814b by the second first verification interval 824. If no beacon signal is detected, the wireless terminal will continue to increase the search frequency by the Step size 818 and repeat the search procedure. If a beacon signal is found, as shown in the example, the wireless terminal proceeds to the second step. Note that the beacon signal detected in the first step may be a carrier beacon signal or another type of beacon signal. If the search band partially overlaps with the service band, then there is a possibility that the detected beacon signal is not a carrier beacon signal and the carrier band may not uniformly cover the frequency beams of the carrier radio beacon. This is the case of the example of Figure 4, the detected beacon 826 is a beacon of the slope / sector type 812, and the search band 814b does not cover the tone of a carrier beacon 810. At the start of the second step, the The wireless terminal first adjusts the search frequency to ensure that the adjusted search band 814c will cover the carrier beacon. For example, assume that the carrier beacon is smaller than either the dependent beacon or sector in frequency, as in the case of the example in Figure 4. Then, the wireless terminal can adjust the search frequency, so that the tone radio beacon detected locate at the upper end of the adjusted search band or at the upper end of the possible beacon tone location within a given search band. In the example of Figure 4, the wireless terminal has set the search band 814 by an amount 820 of the search band 814b to the search band 814c, which places the frequency of the detected beacon 826 near the top of the band 814c. The search band 814c includes the frequency used by the carrier radio beacons. The wireless terminal proceeds to check the downlink signal of the adjusted search band 814c for a second verification time interval 828, which is in the order of a small number of ultra-slots. For example, the second verification time interval is set to be slightly larger than the ultra-interval. For example, in an exemplary mode where the ultra-interval is approximately 1.44 sec, the second verification interval can be set to 1.5 sec. In the second verification time interval 828, the wireless terminal can detect multiple beacon signals. The wireless terminal shall identify those beacon signals 830, 832 associated with the carrier beacon tone according to the characteristics of the bearer radiobeacon tone. For example, in some embodiments, the signal from the carrier beacon repeats exactly one ultra-interval. In some embodiments, the tone of the carrier beacon is the lowest frequency beacon tone in the service band. In some embodiments, the tone of the carrier beacon is the highest frequency beacon tone in the service band. In some modalities, the tone of the carrier beacon is fixed, while in other types of beacon tone, for example, slope / sector beacon tones, the frequency jumps with time. The flow diagram 400 of Figure 5 shows an exemplary method for locating the carrier frequencies, according to the invention. In step 402, the carrier search method is started by the wireless terminal, for example, when the wireless terminal turns on and initializes at an unknown location. Proceeding to step 404, the wireless terminal sets the search frequency (SF) to a minimum frequency. In other embodiments, the initial search frequency may be set to a value corresponding to the last known search band encompassing the last known carrier frequency. The operation proceeds to step 406, where the wireless terminal verifies a 1.25 MHz band concentrated around SF by a beacon signal from the base station. Next, in step 408, the wireless terminal checks whether a beacon was detected within the first time interval. That is, if the beacon interval is approximately 90 msec, then the first time interval may be between 90 and 180 msec. That is, the wireless terminal can verify the existence of a beacon signal in the 1.25 MHz band concentrated around SF during 990 or 180 ms. If a beacon signal is detected within the first time interval (e.g., 180 msec) from the start of verification in the current band, then the operation proceeds to step 428 after beacon detection; however, if a beacon signal is not detected within the first time interval of the start of verification in the current band, the operation proceeds to step 410. Assuming that a beacon signal was detected in step 408, then the operation proceeds to step 428, where the SF is adjusted so that the detected beacon tone is located at the upper end of the adjusted search band. The operation proceeds to step 412. Finding a beacon means that the search band, including the carrier frequency and carrier frequency beacon have been found. Now, the carrier beacon can be located by continuing the verification of the beacons within the current search band, and waiting until a beacon and identified beacon (distinguished from dependent beacon / sector) is detected by the wireless terminal. In step 412, a determination is made to see if any beacon detected in the current band can be identified as a beacon beacon. The slope and sector radiobeacons jump with time after a jump sequence. In some embodiments, the carrier beacon can be identified as a beacon signal that does not follow the jump sequence. In some embodiments, the carrier frequency can be identified as a beacon signal occurring at a predetermined approximate position in the search band, eg, lower in the search band than slope or sector beacons. Since the carrier frequency beacon is fixed and repeats at a fixed time interval, the wireless terminal can, in some modalities, wait to receive two beacons successive carriers to make a positive identification. If in step 412, the carrier beacon has not yet been identified, the operation proceeds to step 414, where the wireless terminal continues to check for additional beacon signals. In step 416 checks are made periodically to see if an additional beacon signal has been detected. When another beacon signal is detected in step 416, the operation proceeds to step 412, where again a check is made to see if any beacon detected in the current band can be identified as a detected beacon. If the verification in step 416 reveals that a beacon operation has not been detected, the operation proceeds to step 418, where a delay time check is performed. In step 418, the wireless terminal tests to see if the second verification time interval (e.g., 1.5 sec) has elapsed since the first beacon in the current set was detected. In the example, the carrier radiobeacons are repeated every 1.44 sec. If the interval of 1.5 sec (a delay time) has not elapsed, then the operation proceeds to step 414 where the beacon verification continues. However, if the 1.5 second delay interval has passed, then the terminal has been unable to acquire and successfully identify a beacon beacon within a reasonable range for example, the quality of the signal channel has decreased below an acceptable level since the first beacon (dependent / sector) of the signal was detected. current set. In step 417, the search frequency is increased by a one-step increase, for example, 1.25 MHz, by switching to a new search band. In step 417, the operation proceeds to step 406, where the search continues using the new search band. Returning to step 412, if a beacon detected in the current search band can be identified as a carrier beacon, the operation proceeds to step 420. In step 420, the carrier downlink frequency is set on the basis of the carrier frequency detected and identified. There may be a predetermined and known deviation between the frequency of the carrier beacon and the carrier frequency of the downlink. Next, in step 422, the wireless terminal, using the carrier frequency of the determined downlink, listens to the downlink channel for information that allows the bearer frequency of the uplink to be determined. In some modalities, the carrier ascending may be at a fixed deviation of the downlink carrier. In some embodiments, the fixed deviation between the bearers of the downlink and the uplink may be previously known by the wireless terminal, and the signaling step 422 may be omitted. Next, in step 424, the wireless terminal sets the uplink carrier frequency and normal communications between the wireless terminal and the base station can proceed. In step 426, the search operation ends. In step 422, the wireless terminal can also obtain other system information, such as an identifier of the service provider that is currently operating the service band. The wireless terminal can compare the sought identifier of the service provider with its own service agreement to determine if it has access to the detected service band. In addition, the strength of the detected beacon signal energy informs the wireless terminal about the quality of the service band channel, on the basis of which the wireless terminal can determine whether it has access to the detected service band. . Returning to step 408, if a beacon signal was not detected within the first interval of time, the wireless terminal can assume that it is searching in the wrong search band; therefore, the operation proceeds to step 410. In step 410, the search frequency is increased by a step size, for example, 1.25 MHz, and a new search band is established. The operation proceeds from step 410 back to step 406, where it initiates the verification of radio beacons in the new search band. The process of incrementing in steps 410, 417 can be set to verify, if the current SF is the maximum allowable SF, in which case a search band transition would be the minimum permissible SF, instead of the 1.25 MHz increase. Previous times and frequencies are intended to be exemplary and may vary depending on the particular implementation of the system. Figure 6 illustrates an exemplary communications system 10 implemented in accordance with the invention. Although shown by a sector per cell 1, Figure 6, in some embodiments, some or all of the cells in the system may be ultisector cells. The exemplary system 10 includes a plurality of cells (cell 1 (2), cell 2 (2 '), cell M (2").) Each cell (cell 1 (2), cell 2 (2'), cell M ( 2")) represents a wireless coverage area for a base station (BS 1 (12), BS 2 (12 '), BS M (12"), respectively At least two base stations in different locations in the system 10 use different service bands Some of the base stations in the system 10 may have areas of cellular coverage that overlap, and some base stations may have cellular coverage areas that do not overlap the areas of other BSs in system 10. System 10 also includes a network node 3 coupled to base stations (BS 1 (12), BS 2 (12 '), BS M (12")) via network links (4, 4', 4"), respectively. The network node 3, for example, a router, is also coupled to the Internet and other network nodes via the network link 5. The network links (4, 4 ', 4", 5) may be, for example, fiber-optic links Each cell includes a plurality of wireless terminals that are coupled to the base station of the cell via wireless links, and if the wireless terminals are mobile devices they can then be moved through the system 10. In cell 1 (2), multiple wireless terminals (WT 1 (14), WT N (16)), shown as nodes (MN 1 (14) through MN N (16)) , communicate with the base station 1 (12) through the use of communication signals (13, 15), respectively In cell 2 (2 '), multiple wireless terminals (WT 1' (14 '), WTN' (16 ')), shown as mobile nodes (MN l '(14') to MN N '(16')), communicate with the base station 2 (12 ') through the use of communication signals (13', 15 '), respectively. In the M cell (2"), multiple wireless terminals (WT 1" (14"), WTN" (16")), shown as mobile nodes (MN 1" (14") up to MN N" (16")) , communicate with the base station M (12") through the use of communication signals (13", 15"), respectively. Each mobile terminal may correspond to a different mobile user and are therefore sometimes referred to as user terminals. The signals (13, 15, 13 ', 15', 13", 15") can, for example, orthogonal frequency division multiplexing (OFDM) signals. The base stations (12, 12 ', 12") transmit emission signals, including beacon signals that carry carrier information, according to the methods of the present invention, the mobile nodes (14, 16, 14', 16 ' , 14", 16") implement the bearer search method of the invention after being established, entering a new cell, and / or after the loss of a carrier signal.The base stations (12, 12 ', 12") and the wireless terminals (MN 1, MN N, MN 1 ', MN N', MN 1", MN N") (14, 16, 14 ', 16', 14", 16") each implement the method of the present invention. In this way, the signals (13, 15, 13 ', 15', 13", 15") include signals from the type discussed in this application, which are transmitted according to the invention. Figure 7 illustrates an exemplary base station access node 200, implemented in accordance with the invention. The base station 200 can be any exemplary BS 12, 12 ', 12"of Figure 6. The base station 200 transmits beacon signals, eg, beacon signals as those illustrated in Figure 1 or Figure 2. Different beacons they are transmitted at different times The beacon signals transmitted in any cell can be dependent on the cell and / or sector with different cells / sectors transmitting different beacon signals The base station 200 includes a receiver 2020, a transmitter 204, a processor 208, an I / O interface 210, and a memory 212 coupled together with the channel 214 on which the different elements can exchange data and information.The base station 200 includes a receiving antenna 216 coupled to the receiver 202 through which the BS 200 can receive uplink signals from a plurality of wireless terminals The base station 200 also includes the transmission antenna 218 coupled to the transmitter 204 through which the BS 200 sends signals on the downlink, including emission signals and signals user-specific to a plurality of WT. The emission signals include: beacon signals including bearer beacon signals, and in some embodiments, bearer information related to the bearer downlink information to the bearer link information. The receiver 202 includes a decoder 220 for decoding the uplink signals received while the transmitter 204 includes an encoder 222 for encoding data / downlink information before transmission. The I / O interface 210 couples the base station 200 to the Internet and / or to other network nodes, for example, other base stations, AAA server nodes, home agent nodes, routers, etc. The memory 212 includes routines 224 and data / information 226. The processor 208, for example a CPU, executes the routine 224 and uses the data / information 226 in the memory 212 to cause the base station 200 to operate according to the invention. The routines 224 include communication routines 228 and base station control routines 230. The communication routines 228 are used to control the base station 200 to perform various communication operations and implement various communication protocols. The control routines of the base station 230 are used to control the base station 200 to implement the steps of the method of the present invention. The control routine of the base station 230 includes a programming module 232, beacon routines 234, and identification signaling module (ID) of the uplink carrier 240. The programming module 232 is used to control the transmission schedule and / or allocation of communication resources. In this way, the module 232 can serve as a programmer. The beacon routines 234 control the determination, generation and transmission of beacon signals by the base station 200. The beacon routines 234 include beacon generating and determining module 236 and a beacon transmitting module 238. The determination module and beacon generation 236 uses the data / information 226, including the timing information 248 and the beacon structure information 242 to determine the current beacon interval information 246 and generates a beacon signal corresponding to the beacon interval information. current beacon 246. The beacon transmitting module 238 uses the data / information 226 including the current beacon interval information 246 and timing information 248 to control the transmission of a beacon signal generated at the appropriate time. The uplink bearer ID signaling module 240 uses the data / information 226 including the information of the uplink bearer 276 to control the generation and transmission of downlink emission signals that carry information to the WTs that will allow the carrier frequency of the uplink is determined. For example, a WT that has already established the downlink carrier frequency, for example, through a carrier search method according to the present invention, can receive the broadcast signal by providing the deviation between the uplink carriers and the downlink used by the base station 200. The data / information 226 includes information of the beacon structure 242, bearer information 244, current beacon interval information 246, timing information 248, and data / information of the wireless terminal 250. The information of the structure of the beacon 242 includes information that defines the characteristics of the beacon signal to be determined, generated and transcribed by the WT 200. The structure information of radio beacon 242, includes type information 252, tone information 254, timing information 256, jump information 258, sequence information 260, number of intervals / ultra-intervals of beacon 262 and power information 264. Information of type 252 it includes information that defines the different types of beacons transmitted by the BS 200, for example, carrier beacons, slope radio beacons, sector beacons. Type 252 information may also include classification information of the beacon as if a particular beacon uses the same tone or set of tones to carry information or if the particular beacon uses different tones or sets of tones at different times, for example, after of a sequence of tone jumps. For example, in some modalities a carrier radio beacon uses the same fixed tone while the slope and sector beacons use different tones at different times according to a jump sequence. The tone information 254 includes information that identifies the tones or sets of tones used by the beacons transmitted from the BS 200. The tone information may also include information identifying a range of tones within the range of Downlink service that can carry radio beacon signals, for example, the bandwidth of the range of tones used for the signaling of a beacon may, in some embodiments, be less than the bandwidth of the service band. The timing information 256 includes information that defines when a beacon signal will be transmitted. For example, in some embodiments, a beacon signal is transmitted during each beacon interval during a predetermined and fixed OFDM symbol transmission interval of the beacon interval. Jump information 258, for example an equation or jump values that can be used to derive a jump sequence, is used to determine the tone or set of tones used by a beacon that was skipped, during the particular beacon interval within of the ultraintervalo. For example, in one mode, the first beacon in the ultrainterval is a carrier beacon, and the remaining beacons are beacon and sector beacons, the remaining beacons alternate between dependent beacons and sector at successive beacon intervals. The number of radio-beacon intervals per ultra-interval 262 includes information that identifies the number of radiobeacon intervals successive in an ultrainterval, each beacon interval of successive ultra-intervals having the same beacon signal. The power information 264 includes information that identifies the transmit power levels of each beacon signal. In some embodiments, each beacon signal is transmitted at a predetermined power level much greater than the power level used by the data signaling and control of the common downlink. Carrier information 244 includes downlink bearer information 274 and uplink bearer information 276. Carrier information 244 is location-dependent. For example, a base station of a service provider 200 may have different service bands for different locations. The downlink carrier frequency information 274 includes the carrier frequency information 278 and the service band information 280. The carrier frequency information of the downlink 278 includes the bearer used by the BS 200 for signaling by the downlink, for example, the downlink bearer within the unconventional band for which WT is being searched. The service band 280 information includes the range of frequencies used for downlink signaling by the BS 200. In some embodiments, the service band is centered around the carrier frequency of the downlink. The information in the service band 280 also includes the bandwidth of the service band. In some embodiments, the bandwidth of the service band remains constant throughout the system, but the carrier frequency changes from place to place. The information of the uplink bearer 276 includes the carrier frequency information 282 and the service band information 284. The uplink carrier frequency information 282 includes the bearer used by the BS 200 for signaling over the link ascending, for example, the uplink carrier within the unconventional band. The service band information 284 includes the frequency range used for uplink signaling by the BS 200. In some embodiments, the service band is centered around the uplink carrier frequency. The service band information 284 also includes the bandwidth of the service band. In some embodiments, the bandwidth of the service band remains constant through the system, but the carrier frequency changes from place to place. In some embodiments, the intersection of the uplink bearer to the downlink is a fixed deviation and remains constant throughout the system. In some embodiments, the intersection of the uplink to the downlink carrier may vary from place to place. In some embodiments, the uplink bearer ID signaling module 240 performs operations to carry information to the WTs corresponding to the inter-carrier spacing and / or other information of the uplink bearer. The current beacon interval information 246 includes the interval index 266 and tone information 268. The range index 266 is the index of the beacon interval within the ultrainterval corresponding to a beacon signal. The information 268 includes a tone or set of tones comprising the current beacon signal and the associated power levels concentrated on that tone or tones. The timing information 248 includes the timing of transmission of OFDM symbols, for example, the tracking of the transmission time intervals of successive OFDM symbols within one radiobeacon and ultrainterval interval as time progresses. The WT 250 data / information includes a plurality of WT data information sets (data / information from WT1 270, data / information of WTN 272). The WT1 270 data / information includes a set of data / information corresponding to the WT1 such as, for example, active sessions, users, by nodes in communication sessions with WTN, routing information, user data / information, user information. resources, for example, identifiers assigned to the BS200, segments of the traffic channel allocated to the uplink and the downlink and dedicated control segments. The servers and / or host devices may be implemented using circuits which are the same as, or similar to, the access mode circuits of the exemplary base station 200, eg, the access router, shown in Figure 4, but with interfaces and / or control routines appropriate to the requirements of the particular host / server device. The routines and / or control equipment in those servers and / or hosts cause the device to implement the methods of the present invention.

Figure 8 illustrates an exemplary wireless terminal (end node) 300, for example, a mobile node, implemented in accordance with the present invention that is capable of performing the search method of the bearer of the invention. The exemplary WT 300 may be any of the WTs (14, 16, 14 ', 16', 14", 16") of Figure 6. The mobile node 300 may be used with a mobile terminal (MT). The wireless terminal 300 includes a receiver 302, a transmitter 304, a processor 306, a user I / O device 308, and a memory 310 coupled together via channel 312 on which different elements can exchange data and information. The memory 310 includes routines 322 and data / information 324. The receiver 302 is coupled to a receiving antenna 316 through which the WT 300 receives downlink signals from the BS including: beacon signals carrying carrier information, and in some embodiments, emission signals of the BS carrying information linking the downlink bearer with the uplink bearer. The receiver 302 includes a decoder 314 for decoding the received encoded downlink signals. The transmitter 304 is coupled to a transmitting antenna 320 through which the uplink signals, including the traffic channel signals of the link upstream, they are brought to the BS from the WT 300. The transmitter 304 includes an encoder 318 for encoding data / information in the uplink signals coded prior to transmission to a base station. In some embodiments, the decoder 314 and the encoder 318 use low density parity check codes (LDPC). The processor 306, for example, a CPU, executes the routines 322 and uses the data / information 324 in the memory 310 to control the operation of the WT 300 and implements methods of the present invention including the search of the bearer. The user 1/0 devices 308, for example, the keyboard, numeric keypad, mouse, microphone, camera, screen, loudspeaker, etc., allow the user of the WT 300 to feed user information that is intended to be for the modes personal and to send data / user information received from personal modes. The routines 322 include the communication routine 326 and control routines of the wireless terminal 328. The control routines of the wireless terminal 328 include the carrier search routine 330, the downlink bearer establishment module 332, the module determining the uplink carrier 334, and the uplink carrier establishment module 336.

The communication routines 326 implement the different communication protocols used by the WT 300. The control routines of the WT 328 control the operation of the WT 302 receiver, the transmitter 304, the user I / O devices 308, and implement the methods of the present invention. The carrier search routine 330 causes the WT 300 to implement a carrier search method in accordance with the present invention. The carrier search routine 330 includes search start module 338, a beacon verification and detection module 340, a timing module 342, a check band adjustment module 344, and a carrier detection module 346. The search start module 338 uses the data / information 324, including the search start information 368 and, in some embodiments, stored carrier information 352, to select a first frequency band to be verified when start the search The information belonging to this interval to be searched is stored by the module 338 in the information of the current search band 356. For example, in some modalities or under some set of conditions, the search start module 338 starts the search in a band at the most extreme lower band of the downlink to be searched as identified in the search start information 368. In another mode or under some other set of conditions the start of the search 338 starts the search in a band identified in the stored carrier information 352, eg, a band from a set of downlink service bands previously used as the last previously used downlink service band. The search start module 338 is tuned to the receiver of the WT 302 to select the current search band. The beacon 340 verification and detection module uses the data / information 324 including the system information 350 and the current search band information 356 to perform the verification and signaling the downlink within the current search band to detect and identify the beacon signals. For example, the received beacon signals can be recognized by the characteristics of the high concentrated power over one or a few tones. When the beacon detection and detection module 340 detects a beacon signal, the information, for example, the tone and timing information, corresponding to the The detected beacon signal is stored in the information of the detected beacon 358. In some embodiments, a beacon signal detected by the module 340 interrupts and / or terminates a verification interval, and activates an additional operation, for example, an adjustment of service band and the start of a different type of verification interval. In another embodiment, the beacon verification intervals are not interrupted or terminated prematurely by the detection of one or more beacon signals. The timing module 342 uses the data / information 324 to control the timing operations including: beginning of the verification intervals, monitoring the time consumed in a first or second type verification interval, verifying whether the verification interval has expired , and activation of additional operations when a verification interval expires. The timing module 342 stores information in the timing information 354. The check band adjustment module 344 uses data / information 324 which includes the information of the size of the search step 368 or information of the search setting 376 to adjust the information of the current search band that changes the search band 356. For example, if a first time interval has expired of according to the indicated by the timing module 342 without the detection of a beacon signal by the radio beacon verification and detection module 340, then the check adjustment module 344 can increase the current search band in the size of a step and check the receiver 302 to return to the new search band, and the adjustment module of the verification band 344 may signal the timing module to initiate a second first verification time interval. As another example, consider that the radiobeacon verification and detection module 340 has detected a beacon signal within a first verification interval, the verification band adjustment module can change the search band according to the information of search setting 376, for example, by lowering the search band, so that the detected beacon signal is placed at the top of the new search band. The adjustment module 344 stores the new information of the search band in the information of the current search band 356, controls the receiver 302 to return to the new search band, and signals the timing module 342 to initiate a second interval of verification time. The carrier detection module 346 uses the data / information 324 including the information of the detected beacon 358 and information of the system 350 to obtain the information of the detected carrier signal 360 and determine the information of the downlink carrier 362. For example, the information of the beacon detected 358 during the second verification interval may include information indicating that two beacon signals have been received at the same fixed tone and are separated by the time interval of an ultrainterval, indicating by the information of the beacon structure 382 that a signal has been detected. carrier beacon and the carrier detection module obtains the information of the detected carrier signal 360. Then, using the information of the carrier / service band DL 378, for example, the information indicating the carrier frequency and the associated service band in relation to the carrier beacon tone, for example, a deviation fixed between the tone of the carrier beacon and the carrier frequency and / or the position of the carrier beacon's turn with respect to the limit of a service band, the carrier detection module 346 determines the information of the downlink carrier 362. The fixation module of the downlink carrier 332 uses the data / information 324 which includes the information of the determined downlink bearer 362 for setting, for example, tuning, the receiver 302 or the carrier frequency and the service band. The ascending link bearer determination module 334 determines the bearer and the service band to be used by the WT 300 for uplink signaling. In some embodiments, there is a fixed relationship between the bearers of the downlink and the corresponding uplink through the system. In that embodiment, the determination module and the uplink bearer 334, after the downlink bearer has been determined, use the data / information 324 which includes the information of the determined downlink bearer 362 and the bearer information. DL / Uplink bearer 380, for example, a stored fixed deviation, to determine the information of the UL builder 364. In some embodiments, the separation between the bearers of the downlink and the corresponding uplink changes for different locations of the base station in the systems, for example, as shown in Figure 3. In one embodiment, after the WT 300 has tuned its receiver to the determined DL bearer, the WT 300 receives and processes, using the 334 module as an emission signal. of the BS indicating the information that can be used to derive the determined UL bearer information 364. For example, the broadcast signal can indicate the UL carrier frequency or the broadcast signal can indicate a deviation of the carrier frequency of the uplink of the carrier frequency of the downlink. The uplink carrier fixation module 336 uses the data / information 324 which includes the information of the determined UL bearer 364 for setting, for example, tuning, the transmitter 304 so that the WT can transmit uplink signals to the station base to the appropriate service band. The data / information 324 includes user data 348, system information 350, stored carrier information 352, timing information 354, current search band information 356, detected beacon information 358, detected carrier signal information 360 , determined downlink bearer information 362, determined uplink bearer information 364, and user / device / session / resource information 392. User data includes data and information, for example, voice, text, application of the user, and video data / information to be communicated to / received from persons of the WT 300 in communication sessions with the WT 300. The information of the system 350 includes the information of the range of the search band 366, search start information 368, information of the first verification interval 370, information of the second verification interval 372, information of the size of the search step 374, search adjustment information 376, information of the carrier / service band of the downlink 378, downlink bearer / downlink bearer information 380, and beacon information 381. The search band range information 366 includes information identifying the downlink band to be searched, by example, the downlink band within an unconventional band. The range information of search band 366 also includes limits on range, including a minimum frequency and / or a minimum search adjustment frequency. The information or start of the search 368 includes information identifying the initial search band to be used, for example, a search band in the lowest position in the downlink band to be searched and / or information that identifies a search start technique to be used, for example, the use of the last successfully determined service band that has been stored in the stored carrier information 352. The information of the first verification interval 370 includes information that identifies the duration of the first verification time interval in which the operation will proceed to a second verification time interval if any beacon has been detected during the first verification time interval. The first verification time interval 370 also includes information identifying whether the first verification interval ended upon detection of a beacon signal or whether the first verification interval was completed before proceeding to a second verification time interval. In some embodiments, the first verification time interval is set in the interval of 1 to 2 intervals of the beacon interval or slightly longer. For example, in an exemplary embodiment with a beacon interval of 90 msec, the first verification interval is set at 180 msec. The information of the second verification interval 372 includes information identifying the duration of a second verification time interval in which the search band was searched to identify a carrier radio beacon. The second verification time interval 372 also includes information identifying whether the second verification interval ended after the determination of a carrier beacon signal or whether the second verification interval was completed before proceeding to the use of the determined carrier information. In some embodiments, the second verification time interval is set in the interval of 1 to 2 ultra-intervals or slightly longer. For example, in an exemplary mode, where an ultrainterval is 1.44 sec, the second verification interval is set at 1.5 sec. The range of the size of the search step 374 includes information identifying the quantity to be changed, for example, the deviation at a higher frequency, the current search band, after completing a first type verification interval without the detection of a signal of radio beacon. The search adjustment information 376 includes the information used to control the amount of adjustment, i.e., deviation, of the current search band after detection of a beacon signal during a first verification interval. For example, in some modes, a carrier beacon is in a fixed frequency position in the service band which is it finds a lower tone than any other beacon signal and the beacon tones occupy some interval of the defined subset of the service band. In that embodiment, the search adjustment information 376 may include information used to determine where to place the search band with respect to the detected beacon to ensure that a carrier beacon will be detected during the second verification interval, e.g. the carrier band so that the detected beacon signal is at the top of the search band. Bearer / downlink service band information 378 includes information identifying the relationship between the downlink bearer and the downlink service band, for example, the downlink service band is centered around the bearer of the downlink and occupies a specified bandwidth. The information 378 also includes information that identifies the relationship between the carrier beacon and the carrier frequency, eg, the number of tones and the address, lower or higher, than the tone of the carrier beacon deviated from the carrier frequency. The information of the downlink bearer / link bearer ascending 380 includes the information used to determine the uplink carrier frequency of a base station based on a detected downlink bearer. For example, in some embodiments, the uplink bearer is at a fixed deviation from the downlink bearer, and that fixed uplink / downlink bearer separation value is stored in the information 380. In some embodiments, the separation of the uplink / downlink carrier varies from place to place, and each BS sends a broadcast message with information that can be used by the WT 300 to derive the uplink bearer of the message. In one of those embodiments, the information 380 includes information that identifies the broadcast message and the parameters used to derive the uplink bearer from the bypass message and / or determine the bearer of the downlink. The information on beacon 381 includes information on the structure of beacon 382. Beacon 382 structure information includes beacon type information, tone information, timing information, jump information, sequence information, number of radiobeacon intervals / ultraintervals, and information of power. The exemplary beacon structure information 382 is similar to the beacon structure information 242, previously described with respect to the exemplary BS 200. The stored bearer information 352 includes a trainer on carriers and service bands that have previously been found by a bearer search operation and may have previously been used by the WT 300 for communications. The stored carrier information 352, in some embodiments, includes a timestamp and / or frequency of the usage information of each of the stored carrier information sets. In that mode, the WT 300 can start a carrier search on the last carrier used or the most frequently used carrier. The timing information 354 includes the transmission timing of OFDM symbols, for example, a tracking of the transmission time intervals of successive OFDM symbols within a beacon and ultra-interval interval as time progresses. The timing information 354 also includes timing tracking information such as the time remaining in a first verification interval or the time remaining in a second verification interval.

The information of the current search band 356 includes information identifying the parameters of the current search band, for example, frequency and bandwidth. The information in the current search band 356 also includes information that identifies when the search of the current search band has begun. The information of the detected beacon 358 includes information pertaining to the beacons detected during the first verification intervals and the second verification interval including: the tone or tones used by each detected beacon, timing of the beacon within the ultra-interval, type of beacon, etc. For example, a first beacon can be detected during the first verification interval and at least a second verification interval can be detected during the second verification interval. The information of the detected carrier signal 360 includes the frequency of the carrier signal that has been determined from at least the frequencies of the first and second beacon signals detected. The information of the determined downlink carrier 362 includes the carrier frequency information 384, for example, the information of the carrier 360, and its corresponding service band information 386, eg, a bandwidth of the downlink service band and information identifying the position of the downlink carrier within the service band, for example, centered. The information of the determined uplink bearer 364 includes the information of the carrier frequency 388, for example, of the ascending link bearer determination module 334, and the corresponding service subband information, eg, a bandwidth, of the uplink service band and information identifying the position of the uplink bearer within the service band, for example, centered. The user / device / session / service information 392, for example, user / device identification information, session information including personal node identification and routing information, resource information, such as segments of the allocated uplink and downlink traffic channel, and control channel segments for the WT 300, can be accessed and used to implement the methods of the present invention, and / or data structures used to implement the invention.

Figure 9 is a flow chart 900 of an exemplary method for operating a base station, for example, to BS 200, for transmitting beacon signals according to the present invention. The operation begins at step 902, where the base station is turned on and initialized. As part of the initialization, the beacon interval index can be set to one, the lowest index beacon interval in an ultrainterval. The operation proceeds from step 902 to step 904. In step 904, the base station is operated to obtain the beacon interval index within the ultrainterval. Each beacon interval is a non-superimposed time interval with respect to the adjacent beacon intervals. Each ultrainterval includes a fixed number of radio beacon intervals. The operation proceeds from step 904 to step 906, where the base station determines the type of beacon and tone designation for the next beacon signal based on the beacon interval index. Each radio beacon is one of a plurality of different types of radio beacons, each radio beacon of the different types that is transmitted in a different tone or set of tones within the same frequency band. In some embodiments, a first type of beacon signal has a location of fixed frequency with respect to the lowest tone in the frequency band. In some embodiments, the first type of beacon has a fixed frequency location which is smaller or larger than all other types of beacons transmitted by the base station within the service band. In some embodiments, the first type of beacon signal is referred to as a beacon beacon. In some modalities, other types of beacon radiobeacon include slope and / or sector beacons. In some modalities, the slope and / or sector radiobeacons use frequency tones that jump over time. In some embodiments, the first type of beacon signal, eg, the carrier beacon, occurs less frequently than other types of beacon signals, eg, a carrier ultra-high-range beacon, and beacon signals of the slope / multiple sector type. by ultrainterval. Next, in step 908, the base station is operated to generate the beacon signal according to the information determined from step 906. Then, in step 910, the base station is operated to transmit the beacon signal generated during the beacon interval, for example, during the OFDM symbol transmission time interval designated for a beacon signal transmission. The operation proceeds from step 910 to step 912. In step 912, the base station is operated to verify whether the index in the beacon interval is equal to the index of the highest beacon interval in the ultrainterval. If the beacon interval index is equal to the highest beacon interval index in an ultrainterval, then the signaling of the beacon for the ultrainterval has been completed, the operation proceeds to step 914. Within a complete ultrainterval, the base station has transmitted each radio beacon of a different type at least once. In step 914 the base station is operated to set the index of the beacon interval equal to one, representing the first beacon interval of a new ultrainterval. However, if in step 912, it is determined that the radiobeacon interval index is not equal to the highest beacon interval index in the ultrainterval, then the operation proceeds to step 916. In step 916, the base station is operated to increase the beacon interval index. The operation proceeds from step 914 or step 916, back to step 904. Figure 10A and Figure 10B is a flow chart 1000 of an exemplary method for operating a terminal Wireless (WT), for example, the WT 300, for detecting a carrier signal transmitted by a base station, for example, the BS 200, which transmits beacon signals on a periodic basis, in accordance with the present invention. The exemplary method begins at step 1002, when the wireless terminal is turned on and / or initialized to begin the search method. The operation proceeds from the initial step 1002 to the step 1004. In step 1004, the WT is operated to select a first frequency band to be a verified frequency band. For example, if the wireless terminal was just turned on, the WT can use the last frequency band used by the WT as the first selected frequency band, a frequency band likely based on previous operations of the WT, or a selected band, default, as the lowest frequency band in the range to be searched. The operation proceeds from step 1004 to step 1006. In step 1006, the WT is operated to initiate verification of the first frequency band to detect a beacon signal during a first time interval. For example, the WT tunes a receiver to the selected band of step 1004, initiates signaling reception within the selected verification band, and evaluates any signal received to determine if it is a beacon signal, for example, a beacon signal that is a signal that includes one or more signals of narrow bandwidth, has been received. In some embodiments, the beacon signals may be a plurality of different types, a first type, eg, a carrier beacon signal, being transmitted over a tone having a fixed deviation from the lowest tone in a frequency service band. corresponding, being the first type of beacon signal transmitted using the highest or lowest tone of any of the beacon signals transmitted in the frequency service band. In some embodiments, the operation of detecting a beacon signal includes detecting the energy of the beacon signal without determining the phase of the beacon signal. In some embodiments, the first time interval is a slightly longer interval than a beacon interval, eg, one to two intervals of slightly higher radiobeacon. The operation proceeds from step 1006 to step 1008. In step 1008, the WT checks to see if a beacon has been detected. If a beacon has been detected, the operation proceeds to step 1010; otherwise, the operation proceeds to step 1012. In step 1010, the WT changes the frequency band verified by an amount that is less than the width of the frequency band verified. In some embodiments, under some conditions, the change of step 1010 is a change of zero Hz. In some embodiments, the frequency band verified is changed so that the frequency band verified has the frequency of the beacon signal detected at a Preselected deviation from the upper part of the frequency band verified. In some embodiments, the change of step 1010 is such that continuous verification of the verified frequency band will detect within its band, a beacon signal of the first type, eg, a carrier beacon. The operation proceeds from step 1010 to step 1014. In step 1014, the wireless terminal is operated to initiate verification of the band of • current verified frequency to detect a second beacon signal during a third period of time. For example, the third period of time may be a slightly longer interval than a range including at least one of the beacon signals of the first type, for example, the beacon type signal from which the bearer can be determined. In some modalities, the interval of the third type slightly greater than a uninterrupted interval. The operation proceeds from step 1014 to step 1016. In step 1016, the WT checks to see if a beacon has been detected. If a beacon was detected, the operation proceeds from step 1016 to step 1018. At step 1018, a check is made to see if the detected beacon provides sufficient information to determine the bearer. In different modalities, it may be necessary to detect different numbers of beacons before the bearer can be determined, depending on particular factors in beacon signaling such as number of beacon types, characteristics of beacon types such as, if or no tones jumped for a type of beacon, the pattern of radiobeacon types in a sequence of beacon signals in one of the ultra-ranges. For example, a modality that includes only two types of beacon signals, for example, a carrier type and a cell identifier type, in which the beacon tones assigned to the beacon signals did not jump, and the signals from radiobeacon alternate between the two types, the reception of two successive beacon signals will be sufficient to determine the carrier beacon. As another example, consider a modality, with three types different radio beacons: the carrier, the cell identifier (pending), the identifier of the sector; the carrier beacon uses a fixed tone in the band while the types (slope) and sector use tones which jump over time; the base station transmits a beacon signal at intervals of radio beacon; the types of radiobeacon follow a sequence of (i) beacon type of slope, (ii) beacon of the sector type, (iii) beacon of the slope type, (ív) beacon of the type of sector, (v) beacon of the type of carrier in successive radiobeacon intervals in an ultrainterval or portion of an ultrainterval. In this mode, it may be necessary to detect up to five beacons before determining the carrier. As another example, consider a modality with three different types of beacons: carrier, slope and sector; the carrier beacon uses a fixed tone in the band while the slope and sector beacons use tones which jump over time; the beacon follows a sequence of a carrier beacon during the first beacon interval of an ultrainterval followed by a beacon or sector beacon during each of the remaining beacon intervals of the ultrainterval. In this mode, it may be necessary to detect two successive carrier radiobeacons separated by an ultrainterval to identify the carrier beacon. Assuming that the beacon signals detected, without further, provide sufficient information to determine the bearer, the operation proceeds from step 1018 to step 1020. In step 1020, the wireless terminal is operated to determine at least the frequencies of the first and second ones. second beacon signals a carrier signal frequency which can be used by the wireless terminal to have a communications service. However, if the detected beacon signals, without further ado, do not provide sufficient information to determine the bearer, then the operation proceeds from step 1018 to step 1022. In step 1022, the wireless terminal is operated to verify whether the third period of time has expired. If the third period of time has expired without the wireless terminal detecting enough beacons to determine a carrier, as expected, this may indicate that the WT has moved out of range of the base station since the first beacon was detected, and therefore the wireless terminal should search within a new band. Also, temporary interference may have occurred to prevent detection of the carrier radio beacon. If the third The time period has expired, the operation proceeds from step 1022 via connection node A 1024 to step 1004 to restart the search operation. For example, in this point step 1004 the next band that has not been searched may be selected, or step 1004 may repeat the search of the current band. Returning to step 1022, if the third period of time has not expired, the operation proceeds to step 1026, where the wireless terminal continues to check the current verification band to detect the beacon signal. The operation proceeds from step 1026 to step 1016. Returning to step 1008, if a beacon signal is not detected, the operation proceeds to step 1012, where the WT is operated to verify if the first time period has expired. If the first period of time has not expired, the operation proceeds from step 1012 to step 1028 where the WT is operated to continue verifying the first frequency band to detect a beacon signal during the first time interval. The operation proceeds from step 1024 to step 1008. If the first time period has expired, then the operation proceeds from step 1012 to step 1030. In step 1030, the WT is operated to change the verified frequency band to a second band of frequency verified, the second frequency band being verified different from the first frequency band verified in an amount that is at most the width of the frequency band verified. Then, in step 1032, the WT begins to check the second frequency band to detect a beacon signal during a second time interval. In some embodiments, the second time interval has the same duration as the first time interval. The operation proceeds from step 1032 to step 1034. In step 1034, the wireless terminal is operated to verify whether a beacon has been detected. If a beacon was detected, the operation proceeds to step 1010, otherwise the operation proceeds from step 1034 to step 1036. In step 1036, the WT checks to see if the second time period has expired. If the second period of time has not expired, the operation proceeds from step 1036 to step 1038, where the WT continues to check the second frequency band to detect a beacon signal during the second time interval. From step 1038 the operation proceeds to step 1034. If in step 1036 it was determined that the second period of time has expired, the search for the second frequency band has not been successful, and the operation proceeds via connection node B 1040 to step 1042. In step 1042, the WT checks to see if the end of the verification interval has been reached. If the end of the verification interval has not been reached, the operation proceeds from step 1042 to step 1044; otherwise the operation proceeds to step 1046. In step 1044, the WT is operated to change the frequency band 'verified to another frequency band, the other frequency band being different from the last frequency band verified by an amount which is at most the width of the frequency band verified. In step 1046, the WT is operated to change the verified frequency band to another frequency band, the other frequency band being at the other end of the verification interval. The operation proceeds from step 1044 or step 1046 to step 1048, where the WT begins the verification of another frequency band to detect a beacon signal for a fourth period of time. In some embodiments, the fourth period of time is of the same duration as the first and / or second periods of time. The operation proceeds from step 1048 to step 1050, where a check is made to see if a beacon has been detected. If a beacon has been detected, the operation proceeds from step 1050 via the connection node C 1052 to step 1010. However; if a beacon has not been detected, the operation proceeds to step 1054, where the WT checks to see if the fourth time period has expired. If the fourth period of time has not expired, the operation proceeds from step 1054 to step 1056 where the WT continues to verify the same frequency band to detect a beacon signal during the fourth time interval. The operation proceeds from step 1056 to step 1050. Returning to step 1054, if the fourth time period has expired, the operation proceeds via connection node B 1040 to step 1042. Figure 11 is a flow diagram 1100 of a method exemplary for operating a plurality of base stations in a communications system that includes at least a first and a second base station located in different geographic regions. The first base station uses a first frequency band, while the second base station uses a second frequency band, the second frequency band being different from the first frequency band. The operation begins at step 1102 where the base stations of the communications system are activated. The operation proceeds from step 1102 to steps 1104 and 1106, and optionally, in some embodiments, to steps 1108 and 1110.

In step 1104, a transmitter of a first base station located in the first base station is operated to transmit a plurality of radio beacon signals during a first time period, the plurality of radio beacon signals including a radio beacon signal of a first type. and a beacon signal of a second type, the first time period including a fixed number of second non-overlapping time intervals. Step 1104 includes the operations of sub-step 1112. In sub-step 1112, the transmitter of the first base station is operated to transmit at least one beacon signal within the first frequency band in each of the second time periods, being beacon signals of different types transmitted on different tones within the first frequency band, a beacon signal of the first type and a beacon signal of the second type being transmitted at least once during the first time period. The operation proceeds from the completion of step 1104 at the start of step 1104 for a repetition of the first beacon transmissions of the transmitter of the first base station for another first period of time, for example, the next first successive time period.

In step 1106, a transmitter of the second base station located in the second base station is operated to transmit a plurality of beacon signals during a third time period, including the plurality of beacon signals to a beacon signal of a first type and a radio beacon signal of a second type, the third time period including a fixed number of fourth non-superimposed time intervals. Step 1106 includes the operation of sub-step 1114. In sub-step 1114, the transmitter of the second base station is operated to transmit at least one beacon signal within the second frequency band in each of the fourth periods of time, being radiobeacon signals of different types transmitted on different tones within the second frequency band, a beacon signal of the first type and a beacon signal of the second type being transmitted at least once during the third period of time. The operation proceeds from the conclusion of step 1106 to the start of step 1106 for a repetition of the beacon transmissions of the transmitter of the second base station for another third time period, for example, the next succeeding third period of time.

In some embodiments, for example, various modalities where the intersection of the bearer from the downlink to the uplink varies in the communication system for different base stations in different places, steps 1108 and 1110 are performed. In step 1108, the transmitter of the first base station is operated to periodically transmit in the first frequency band information indicating the frequency location of a frequency band of the uplink to be used. in the transmission of signals to the first base station. In step 1110, the transmitter of the second base station is operated to periodically transmit in the second frequency band information indicating the location of the frequency of a frequency band of the uplink to be used in the transmission of signals to the second Base station. In some embodiments, for example, various modes where the downlink linker to the uplink carrier is fixed in the communication system, the WTs determine a downlink communication band of the BS beacon signaling, for example, step 1104 or 1106, and then knowing the separation of the downlink bearer to the fixed uplink, the WTs determine the carrier band of the uplink without the BS having to communicate additional emission signals. In those embodiments, steps 1108 and 1110 may be omitted. In some embodiments, the transmitters of the first and second base stations transmit orthogonal frequency division multiplexed (OFDM) signals in parallel over a plurality of tones during the first and third time periods. In some embodiments, the first and the third time periods each include a plurality of at least 10, 000 periods of OFDM symbol transmission time. In some embodiments, each first time period includes at least 16 of the second time periods. In some modalities the first and the third periods of time have the same length. In some modalities, the second and fourth periods of time have the same length. In various embodiments, the first and the third time periods are referred to as ultra-intervals, and the second and fourth time periods are referred to as radiobeacon intervals, and each radiobeacon interval includes multiple periods of symbol transmission time. In some embodiments, the radiobeacon signals of the first type are transmitted using a tone having a fixed frequency ratio to the lowest tone in the frequency band in which the first type of beacon signal is transmitted, the frequency band in which the beacon signal of the first type being transmitted a band of downlink frequency. In various embodiments, the tone used to transmit the first beacon signal also has a fixed frequency relationship with the tones in a frequency band of the uplink to be used to communicate information to the base station transmitting the beacon signal of the first kind. In some embodiments, the frequency band of the uplink and the downlink of a pair of frequency bands are distinct and separated from one another by more than one separation between the tones in the frequency band of the downlink. In several embodiments, the first type of beacon signal has a fixed frequency relationship that is smaller or larger than that of all other types of beacon signals transmitted in the frequency band in which the beacon signal is transmitted from the first kind. In some embodiments, transmit at least one beacon signal within the first frequency band in each of the first periods of time it includes transmitting the first type of beacon signal at most one time during the first period of time and transmitting the second type of beacon signal at least twice during the first period of time. In some embodiments, transmitting at least one beacon signal within the second frequency band in each of the fourth periods of time includes transmitting the first type of beacon signal at most once during the third period of time and transmitting the second type of beacon signal at least twice during the third period of time. In various embodiments, transmitting at least one beacon signal within the first frequency band in each of the second time periods includes transmitting a beacon of a third type at least once during the first time period and transmitting at least one signal The radiobeacon within the second frequency band in each of the fourth periods of time includes transmitting a beacon signal of the third type at least once during the third period of time. In some embodiments, the first type of beacon is a beacon beacon signal used to communicate information about the carrier frequency used for communications over the link descending by the base station that transmits the carrier beacon signal. In several embodiments, the second type of beacon signal is the beacon signal identifying the cell type, sometimes referred to as a slope or tilt beacon, which communicates information that identifies the cell from which the beacon signal of the second type was transmitted, and the third type of beacon, if included, is an identifiable beacon signal of the type of sector that provides information about a sector of the base station in which the transmitter of the base station that transmitted the beacon signal of a third type transmits. In various embodiments, the transmitters of the first and second base stations are not temporarily synchronized with each other, for example, several modes in which the transmitters of the first and second base stations are in different cells in different geographical locations. In many-modalities, the transmitter of the first base station is operated to repeat the transmissions of a plurality of beacon signals during a first period of time during multiple sequential first periods of time, and the transmitter of the second base station is operated for repeating the transmissions of a plurality of radio beacon signals during a third period of time during third multiple sequential time periods, the first and third time periods overlap each other. The techniques of the present invention can be implemented using software and software programs or systems, physical computing components or hardware and / or a combination of software and programming systems or software and physical computing or hardware components. The present invention is directed to apparatuses, for example mobile nodes such as mobile terminals, base stations, communication systems that implement the present invention. It is also directed to methods, for example, a method for controlling and / or operating in mobile nodes, base stations and / or communication systems, for example, hosts, according to the present invention, the present invention is also directed to a half readable by a machine, for example, ROM, RAM, CDs, hard drives, etc. which include legible instructions by a machine for controlling a machine to implement one or more steps according to the present invention. In several modalities the nodes described here are implemented using one or more modules to perform the steps corresponding to one or more methods of the present invention, for example, signal processing, generation steps and / or message transmission. Thus, in some embodiments several features of the present invention are implemented using modules. These modules can be implemented using programs and systems of programming or software, physical components of computation or hardware, or a combination of programs and systems of programming or software and physical components of computation or hardware. Many of the methods or method steps described above can be implemented using instructions executable by a machine, such as programs and programming or software systems, included in a machine-readable medium such as a memory device, for example RAM, floppy disk, etc. for controlling a machine, for example, a general-purpose computer with or without additional physical computing components or hardware, to implement all or portions of the methods described above, for example, on one or more nodes. Accordingly, among other things, the present invention is directed to a means readable by a machine that includes instructions executable by the machine to make a machine, for example, processor or physical computing components or associated hardware, perform one or more of the steps of the methods described above. Although described in the context of a system OFDM, at least some of the methods and apparatus of the present invention are applicable to a wide range of communication systems, including many systems not OFDM and / or non-cellular. Numerous additional variations to the methods and apparatus of the present invention described above will be apparent to those skilled in the art in view of the foregoing description of the invention. Those variations should be considered within the scope of the invention. The methods and apparatus of the present invention can be, and in various embodiments are, used with CDMA, orthogonal frequency division multiplexing (OFDM) and / or various other types of communication techniques that can be used to provide wireless communication links. between the access nodes and the mobile nodes. In some modalities the access nodes are implemented as base stations that establish communication links with mobile nodes using OFDM and / or CDMA. In various modalities, the mobile nodes are implemented as notebook computers, personal data assistants (PDA), or other portable devices including receiver / transmitter and logic circuits and / or routines, to implement the methods of the present invention.

Claims (43)

1. NOVELTY OF THE INVENTION Having described the invention as above, property is claimed as contained in the following: CLAIMS 1. A method for operating a plurality of base stations in a communication system, the plurality of base stations including at least one first and second base stations located in different geographic regions, the first base station using a first frequency band, using the second base station a second frequency band which is different from the first frequency band, the method is characterized in that it comprises: operating a transmitter of a first base station located in the first base station to transmit a plurality of radio beacon signals during a first period of time, including the plurality of beacon signals a beacon signal of a first type and a beacon signal of a second type, the first time period including a fixed number of second non-overlapping time intervals, including the step to operate the transmitter of a first base station to transmit r: transmitting at least one beacon signal within the first frequency band in each of the second periods of time, the beacon signals of different types being transmitted on different tones within the first frequency band, being a radio beacon signal of the first type and a beacon signal of the second type transmitted at least once during the first period of time; and operating a transmitter of a second base station located at the second base station to transmit a second plurality of beacon signals during a third time period, the plurality of beacon signals including a beacon signal of the first type and a beacon signal of the second type, the third time period including a fixed number of fourth non-superimposed time slots, including the step of operating the transmitter of a second base station to transmit: transmitting at least one radio beacon signal within the second frequency band in each of the fourth periods of time, the beacons of different types being transmitted on different tones within the second frequency band, the beacon signal being the first type and a beacon signal of the second type transmitted at least once during the third period of time. The method according to claim 1, characterized in that the transmitters of the first and second base stations transmit orthogonal frequency division multiplexed (OFDM) signals in parallel over a plurality of tones during the first and third time periods, including the first and third periods of time a plurality of at least 10,000 times of transmission of OFDM symbols. The method according to claim 1, characterized in that the radiobeacon signals of the first type are transmitted using a tone having a fixed frequency relation with the lowest tone in the frequency band in which the signal was transmitted. radiobeacon of the first type, where the frequency band in which the beacon signal of the first type is transmitted is a frequency band of the downlink. The method according to claim 3, characterized in that the tone used to transmit the beacon signals of the first type also has a fixed frequency relationship with the tones in a frequency band of the uplink to be used to communicate information to the base station that transmits the beacon signal of the first type. The method according to claim 4, characterized in that the frequency bands of the uplink and the downlink are disjoint and separated from each other by more than one separation between the tones in the frequency band of the downlink. 6. The method according to claim 3, characterized in that the radiobeacon signals of the first type are transmitted in the frequency bands of the downlink, the first and second frequency bands being the frequency bands of the downlink, the method is characterized in that it also comprises: operating the transmitter of the first base station for periodically transmitting in the first frequency band information indicating the location of the frequency of an uplink frequency band to be used to transmit signals to the first base station; and operating the transmitter of the second base station to periodically transmit in the second frequency band information indicating the location of the frequency of a frequency band of the link ascending to be used to transmit signals to the second base station. The method according to claim 3, characterized in that the first type of beacon signal has a fixed frequency which is lower or higher than that of all other types of beacon signals transmitted in the frequency band in which the beacon signal of the first type was transmitted. The method according to claim 1, characterized in that the transmission of at least one beacon signal within the first frequency band in each of the second time periods includes transmitting the first type of beacon signal at the most once during the first period of time and transmitting the beacon signal of the second type at least twice during the first period of time. The method according to claim 1, characterized in that transmitting at least one beacon signal within the second frequency band in each of the fourth periods of time includes transmitting the first type of beacon signal at most once during the third period of time and transmitting the beacon signal of the second type at least twice during the third period of time. 10. The method according to claim 9, characterized in that the first and the third periods of time have the same length. 11. The method according to claim 10, characterized in that the second and fourth periods of time have the same length. The method according to claim 11, characterized in that the first and the third time periods are ultra-wide, the second and fourth time periods are beacon intervals, and where each beacon interval includes symbol transmission time periods. multiple The method according to claim 1, characterized in that the transmission of at least one radio beacon signal within the first frequency band in each of the second time periods includes transmitting a beacon signal of a third type at least once during the first period of time; and wherein transmitting at least one beacon signal within the second frequency band in each of the fourth time periods includes transmitting a beacon signal of the third type at least once during the third period of time. 14. The method according to claim 13, characterized in that the radiobeacon signal of the first type is a carrier beacon signal used to communicate information about the carrier frequency used for downlink communications by the transmitter of the base station transmitting the signal. bearer beacon signal. The method according to claim 14, characterized in that the second type of beacon signal is a beacon signal identifying the type of cell that communicates information identifying the cell from which the beacon signal of the second type was transmitted. and wherein the third type of beacon signal is a beacon signal identifying the type of sector that provides information about a sector of the base station to which the transmitter of the base station transmitted the beacon signal of the third type. 16. The method according to claim 13, characterized in that it further comprises: repeating the step of operating the transmitter of the first base station to transmit a plurality of radio beacon signals during a first period of time during multiple first sequential time periods; Y repeating the step of operating the transmitter of the first base station to transmit a plurality of radio beacon signals during a third period of time during third multiple sequential time periods, the first and third time periods overlap each other. 17. The method according to claim 16, characterized in that each first time period includes at least 16 of the second time periods. The method according to claim 17, characterized in that the transmitters of the first and second base stations are not temporarily synchronized with each other. 19. The method according to claim 15, characterized in that the radiobeacon signal of the first type uses a fixed tone; where a tone used by the second beacon signal jumps during the first period of time; and where a tone used by the beacon signal of the third type also jumps during the first period of time. 20. A communication system, characterized in that it comprises: a plurality of base stations in a system of communication, including the plurality of base stations, at least one first and second base stations located in different geographic regions, wherein the first base station uses a first frequency band, including the first base station: i) a transmitter of a first station base; and ii) first transmission control means for controlling the transmitter of the first base station to transmit a plurality of radio beacon signals during a first period of time, the plurality of radio beacon signals including a radio beacon signal of a first type and a radiobeacon signal of a second type, the beacon signals of the different types being transmitted on different tones within the first frequency band, the first time period including a fixed number of second non-superimposed time intervals, the first means of Transmission control causes the transmitter of the first base station to transmit at least one beacon signal within the first frequency band in each of the second periods of time, at least one beacon signal of the first type and one signal of radio beacon of the second type transmitted at least once during each first period of time; Y wherein the second base station uses a second frequency band, including the second base station: i) a transmitter of a second base station; And ii) second transmission control means for controlling the transmitter of the second base station to transmit a plurality of radio beacon signals during a third time period, the plurality of radio beacon signals including a radio beacon signal of a first type and a radiobeacon signal of a second type, the beacon signals of the different types being transmitted on different tones within the second frequency band, the second time period including a fixed number of second non-superimposed time intervals, the second means of Transmission control causes the transmitter of the second base station to transmit at least one beacon signal within the second frequency band in each of the third time periods, with at least one beacon signal of the first type and one signal of radio beacon of the second type transmitted at least once during each third period of time. The system according to claim 20, characterized in that the transmitters of the first and second base stations are orthogonal frequency division multiplexed signal (OFDM) transmitters that transmit orthogonal frequency division multiplexed (OFDM) signals in parallel over a plurality of tones during the first and third time periods, including the first and third time periods plurality of at least 10,000 periods of transmission of OFDM symbols. 22. The system according to claim 20, characterized in that the radiobeacon signals of the first type are transmitted using a tone having a fixed frequency relationship with the lowest tone in the frequency band in which the signal was transmitted. radiobeacon of the first type, where the frequency band in which the beacon signal of the first type is transmitted is a frequency band of the downlink. 23. The system according to claim 22, characterized in that the tone used to transmit the beacon signals of the first type also has a fixed frequency relationship with the tones in a frequency band of the uplink to be used to communicate information to the base station transmitting the beacon signal of the first type. 24. The system according to claim 23, characterized in that the frequency bands of the uplink and the downlink are disjoint and separated from each other by more than the separation ben the tones of a frequency band of the downlink. 25. The system according to claim 22, characterized in that the radiobeacon signals of the first type are transmitted in the frequency bands of the downlink, the first and second frequency bands being, frequency bands of the downlink; wherein the means for controlling the transmitter of the first base station further include: means for controlling the transmitter of the first base station to periodically transmit in the first frequency band information indicating the location of the frequency in a frequency band of the uplink to be used in the transmission of signals to the first base station; and wherein the means for controlling the transmitter of the second base station further include: means for controlling the transmitter of the second base station to periodically transmit in the second frequency band information indicating the location of the frequency of an uplink frequency band to be used to transmit signals to the second base station. 26. A method for operating a wireless terminal to determine a carrier frequency used by a base station that transmits beacon signals on a periodic basis within a frequency band corresponding to the carrier frequency, the method is characterized in that it comprises: verifying a first frequency band for a first period of time to determine whether a beacon signal is present in the first frequency band during at least a portion of the first time period; if during the first period of time, the verification indicates the presence of a beacon signal detected by the verification, performing the additional steps of: i) changing the frequency band verified in a frequency quantity that is less than the width of the frequency band verified; ii) verify to detect a second beacon signal; and iii) determining at least the frequencies of the first and second radiobeacon signals detected a carrier signal frequency that can be used by the wireless terminal to obtain a communication service from the base station. 27. The method according to claim 26, characterized in that the frequency service band is associated with the carrier frequency and where the band of the verified signal has the same frequency width as the frequency service band. The method according to claim 27, characterized in that the frequency service band is a downlink frequency band used to communicate downlink signals from the base station. 29. The method according to claim 26, characterized in that if a beacon is not detected within the first time period, the method further includes: changing the verified frequency band to a second verified frequency band, the second band being frequency verified different from the first frequency band verified in a quantity which is at most the width of the frequency band verified. 30. The method according to claim 29, characterized in that it also comprises: verifying the second frequency band verified during a second period of time to determine whether a beacon signal is present in the second frequency band verified during at least a portion of the second period of time. The method according to claim 30, characterized in that it also comprises: if during the second period of time, the verification indicates the presence of a beacon signal detected by the verification, carry out the additional steps of: i) changing the band frequency checked at a frequency amount which is less than the width of the frequency band verified; and ii) verify to detect a second beacon signal; and iii) determining at least the frequency of the first and second beacon signals detected a carrier signal frequency that can be used by the wireless terminal to obtain the communication service of the base station. 32. The method according to claim 26, characterized in that the verification step for detecting a beacon signal includes detecting the energy of the tones of the received signal. 33. The method according to claim 32, characterized in that the verification step for detecting a beacon is effected before achieving the temporary synchronization of the symbols with the transmitter by transmitting the detected beacon signals. 34. The method according to claim 29, characterized in that the beacon signals can be of a plurality of different types, a first type of beacon signal being transmitted in a tone having a fixed frequency deviation of the lowest tone in the frequency service band, the first type of beacon signal being transmitted using the lowest or highest tone of any beacon signal transmitted in the frequency service band, wherein step i) of changing the frequency band verified by a frequency amount that is less than the width of the frequency band verified includes changing the frequency band verified, so that the frequency band verified has the frequency of the beacon signal detected at a preset fixed deviation from the upper part of the frequency band Verified 35. The method according to claim 27, characterized in that the frequency The determined carrier is a carrier frequency of the downlink, the method is characterized in that it further comprises: determining an uplink carrier frequency for the use of the determined downlink carrier frequency and the stored information indicating a deviation of the uplink carrier from the carrier frequency of the determined downlink. 36. The method according to claim 28, characterized in that it further comprises: determining a carrier frequency of the uplink for the use of the information obtained by the verification of the frequency band of the determined downlink with the carrier frequency information of the uplink. 37. A wireless terminal for use in a system that includes a base station that transmits beacon signals on a periodic basis within a frequency band, the wireless terminal is characterized in that it comprises: means for verifying a first frequency band during a first period of time to determine if a beacon signal is present in the first frequency band for at least one portion of the first period of time; and means to effect, if during the first period of time, the verification indicates the presence of a beacon signal detected by the verification, the additional steps of i) changing the frequency band verified at a frequency amount that is less than width of the frequency band verified; ii) verify to detect a second beacon signal; and iii) determining at least the frequencies of the first and second beacon signals detected a carrier signal frequency that can be used by the wireless terminal to obtain a communication service from the base station. 38. The wireless terminal according to claim 37, characterized in that the frequency service band is associated with the carrier frequency and where the band of the verified signal has the same frequency width as the frequency service band. 39. The wireless terminal according to claim 38, characterized in that the frequency service band is a downlink frequency band used to communicate signals of the downlink from the base station. 40. The wireless terminal according to claim 37, characterized in that the wireless terminal further includes means to effect, if a beacon is not detected within the first period of time, the additional step of: changing the verified frequency band to a second one. frequency band verified, the second frequency band being verified different from the first frequency band verified in a quantity which is at most the width of the frequency band verified. 41. The wireless terminal according to claim 40, characterized in that it further comprises: means for verifying the second frequency band verified during a second period of time to determine if a beacon signal is present in the second frequency band verified during minus a portion of the second period of time. 42. The wireless terminal according to claim 41, characterized in that it further comprises: means to perform, if during the second period of time the verification indicates the presence of a beacon signal detected by the verification, the additional steps of i) changing the frequency band verified at a frequency amount that is less than the width of the frequency band verified; ii) verify to detect a second beacon signal; and iii) determining at least the frequencies of the first and second beacon signals detected a carrier signal frequency that can be used by the wireless terminal to obtain a communication service from the base station. 43. The wireless terminal according to claim 37, characterized in that the carrier frequency is a carrier frequency of the downlink, the wireless terminal further comprises: stored information indicating a frequency deviation of the carrier frequency of the downlink where a signal is located. carrier frequency of the uplink.