KR20010013921A - Wireless device,control system and methods for protected sites with operation according to interference parameters - Google Patents

Abstract

Wireless device 104 operates preemptively near protected sites 110 that include equipment that uses the frequency of operation at least intermittently. Upon detecting the beacon signal from beacon system 112, the wireless device examines the interference parameters. The interference parameters are used to control the operation of the wireless device to prevent harmful interference to the equipment at the protected site. The operation is optionally changed in accordance with the interference parameters investigated. The wireless device can be intelligently controlled from the control system 105.

Description

Wireless device, control system and methods for protected sites with operation according to interference parameters

The emergence of satellite communication systems has resulted in a potential collision between emission from satellite phones and emission electromagnetic radiation from other systems. Radio Astronomy Sites (RAS) are examples of sites that require protection. Equipment at radio astronomy sites measures propagation over time intervals known as integration intervals. During the integration interval, signals emitted near satellite phones can be detected by the RAS equipment. This can lead to errors in the measurements made at these sites. Other sensitive sites where satellite telephone transmissions can interfere are airports where sensitive satellite navigation equipment is used.

Methods have been developed to avoid interference between satellite phones and other systems. This method sends a beacon signal from a site that needs protection. For example, beacon signals are sent from the RAS during the integration interval of the RAS equipment. When the satellite phone detects the beacon signal, the satellite phone is blocked. This prevents emissions from satellite phones that interfere with protected sites. The beacon signal is designed to produce beacon emissions in which the signal's transmit power, antenna pattern, shielding and operating frequency, etc., have no adverse impact on measurement. Although this system is intended to prevent interference, it is desirable to provide a high intelligent beacon system.

The present invention is directed to preventing interference between wireless devices and protected sites.

1 illustrates a satellite communication system and a beacon system.

2 is a circuit diagram in block diagram form illustrating a satellite terminal;

3 is a circuit diagram in block diagram form illustrating a portion of a satellite control system.

4 is a circuit diagram in block diagram form illustrating a beacon circuit;

5 is a flowchart for explaining an operation of a terminal.

6 is a signal diagram showing a spectral mask showing amplitude as a function of frequency.

7 is a flowchart illustrating operation of the satellite control system.

The wireless device optionally operates near a protected site. The wireless device responds to the detected beacon signal. Interference parameters are used to control the operation of the wireless device so as not to interfere with equipment at the protected site. The operation is optionally changed in accordance with the identified interference parameters, such that the wireless device does not necessarily need to be disabled.

Also disclosed is a method of operating a control system that intelligently controls a wireless device near a beacon system.

Also described is a wireless device that selectively operates near a protected site. A control system of wireless devices operating in the vicinity of a protected site is disclosed.

Satellite communication system 100 (FIG. 1) includes satellite 102, satellite terminals 104 in communication with satellite 102, and satellite control system 105 in communication with satellite 102. The satellite control system 105 communicates with other satellite control systems as well as a plurality of satellites. Although a single satellite 102 is shown, it will be appreciated that many satellites 102 are installed in a satellite system.

Thus, satellite 102 represents a network of satellites in communication with satellite terminals 104 and satellite control system 105.

Protected site 110 includes beacon system 112. Equipment at the protected site uses an operating frequency that is affected by interference from satellite terminals 104. The protected site may be an airport, radio astronomy site, or other location with equipment that would be desirable to protect against emissions from satellite terminals 104. For simplicity, it will be appreciated that the following description is based on radio astronomy sites, but may apply to other sites that require protection.

Satellite terminals 104 include a transceiver having a transmitter 206 (FIG. 2) and a receiver 208 connected to an antenna 210. The transmitter 206 and receiver 208 communicate via an antenna 210 under the control of the controller 212. Memory 214 is coupled to controller 212. The controller 212 can be realized using a digital signal processor (DSP), a microprocessor, a programmable logic unit (PLU), or the like. The transmitter 206 and receiver 208 are realized using other suitable transmitter and receiver circuits for satellite communications. The memory 214 may be realized by random access memory (RAM), read-only memory (ROM), electrically programmable read-only memory (EEPROM), or the like. Satellite terminals 104 may be portable satellite phones, vehicle satellite phones, home or business satellite communication systems, mobile satellite multimedia terminals, mobile satellite data terminals, and the like.

In addition to mobile satellite phones, the beacon system can be used if terrestrial communications services interfere with sensitive sites. For protection from terrestrial mobile communications services, communication between mobile telephones and the control system takes place via terrestrial base stations rather than satellites. For simplicity, it will be appreciated that this description is based on satellite systems but applies to other mobile propagation systems. Thus, as used herein, a "wireless device" refers to satellite phones, cellular radiotelephones, cordless radiotelephones, two-way radio waves, and other wireless devices that emit signals that may interfere with equipment at the protected site. The description of satellite terminals applies to each of these wireless devices and their equivalents.

Satellite 102 is a type of orbit around the earth and serves as a repeater for signals communicated between satellite control system 105 and satellite terminals 104. Such satellites are well known and will simply not be described in further detail.

The satellite control system 105 includes a transceiver having a transmitter 302 (FIG. 3) and a receiver 304 connected to the controller 306. The transmitter 302 and receiver 304 are realized using other suitable circuits for satellite communications, and are connected to an antenna such as satellite dish 312. The controller 306 can be realized using a DSP, a PLU, a microprocessor or a computer. Memory 308 is coupled to controller 306. The memory 308 can be executed using RAM, ROM, EEPROM, or the like. The memory 308 stores operating programs, satellite terminal status information, and beacon information for the controller 306. The control system may be a satellite control system, a ground mobile controller such as a cellular base station, a dispatch center, or other wireless device controller, where the "control system" used herein is referred to as each or the equivalent thereof.

The beacon system 112 includes an antenna 404 (FIG. 4) located proximate to the protected site 110. Beacon signals are input from the transmitter 406 to the antenna 404. The transmitter 406 generates a signal having a predetermined frequency and has a frequency of, for example, 1.624 Ghz. Controller 408 is coupled to memory 410 and control input 412. The memory 410 stores an operation program for the controller 408. The control input 412 is used to operate the beacon system. Control inputs are realized using a suitable source of manually operated switches, personal computers, or other control signals. The operation of the beacon can thus be passive or automatic, such that the beacon signal is only generated when protection is required, so that the signal is generated at least intermittently. The controller 408 can be realized using a microprocessor, DSP, PLU, computer, or the like. The controller 408 responds to an operation signal from the control input 412 to control the control transmitter 406 to transmit a beacon signal through the antenna 404.

The satellite terminal 104 selectively blocks the operation of the satellite terminal 104 in response to the beacon signal from the beacon system 112. In the absence of a beacon signal strong enough for the satellite terminal to detect, the satellite terminal 104 operates freely in accordance with normal processes.

Upon detection of the beacon signal, the satellite terminal controller 212 makes several measurements. The signal factor G is measured at block 502 (FIG. 5) as follows.

G = (signal power) / sensitivity

Signal power is a measure of the received beacon signal level. The sensitivity is the minimum signal level that satellite terminal 104 can detect. The sensitivity is predetermined when the satellite terminal is manufactured and is predetermined. It will be appreciated that the sensitivity level may be a predetermined signal level for all satellite terminals of a particular model, based on the typical sensitivity of the receiver of the satellite terminal model. Alternatively, the sensitivity is set individually for each satellite terminal based on actual measurements taken at the factory.

The satellite terminal controller 112 also calculates the α ratio at block 504.

α = (best case interference) / (measured actual interference)

The α ratio depends on the frequency separation between the frequencies used at the satellite terminal 104 and the protected site 110. The worst case interference is the largest possible interference from satellite terminal 104. When the satellite terminal transmits a channel, when the frequency spectrum important to the equipment at the protected site 110 is closest to their respective assigned spectra, when the power level of the transmission signal is the highest possible level, the transmitter is When generating channel signals in the spectral mask of the transmission channel, the worst interference occurs. The spectral proximity between the operating frequency of the protected site 110 and the operating frequency of the satellite terminal 104 is Δf. Thus, for example, the frequency protected in the RAS system is 1.6106 to 1.6138 GHz and the satellite phone transmits channels in the range of 1.6215 to 1.6263 GHz.

The satellite terminal 204 transmission channels have the spectral mask shown in FIG. The mask is the maximum energy that the signals emitted by the transmitter 106 can have as a function of frequency. As shown in FIG. 6, for frequencies far from the allocated spectrum, the mask amplitude is low. Thus, the spectral mask at the accuracy Δf and the maximum power output of the satellite terminal 104 determines the worst case interference. The actual interference is the amount of interference that is expected, given the actual spectral proximity, the spectral mask, and the actual transmit power of the satellite terminal 104. It will be appreciated that the power level of the satellite terminal will change as the path between satellite 102 and satellite terminal 104 changes.

The controller 212 periodically calculates the interference margin β at block 506.

Where β = μ * G ＊ (Pt / Pm) / α

The beacon power is calculated to ensure a single continuous maximum power, Pm, and the transmission assumes the worst case due to unwanted emissions. At a particular point in time, the up-link transmit power of a particular terminal 104 is Pt. The duty cycle μ is the predicted portion of the time that the terminal is transmitting, voice activity, video transmission or data operation (which is the portion of time that the user has data to speak or send) and time division multiple access (TDMA), code division It depends on access methods such as multiple access (CDMA) and frequency division multiple access (FDMA).

The satellite terminal controller 212 determines if the interference margin β is satisfied (ie, if β <1), so that transmission interference with the protected site equipment is below a certain level at decision block 508. If satisfied, the call continues as indicated at block 509. If the interference margin β is not satisfied (ie if β> 1) then the call is aborted. The controller then determines that the transmit power, or transmit bit rate, is reduced, such that at decision block 510, Pt is reduced and the interference margin β &lt; If so, then the satellite terminal controller 212 controls the transmitter 206 to send a signal to the satellite control system 105 requesting this change at block 512, and the call will continue. Otherwise, the controller will determine if another channel is selected so that α is reduced at decision block 512 so that interference margin β <1 is satisfied. If the channel is determined and the interference margin is satisfied, as determined at decision block 514, then the satellite terminal controller 212 then controls the transmitter 206 to request the change at block 516. Signal will be sent to 205, and the call will continue. If the appropriate channel cannot be selected, then the transmitter 206 is disabled at block 518. By disabling only transmitter 206, its satellite terminal can still receive signals.

The satellite terminal controller 212 restarts the transmitter at the end of its beacon transmission period. When the beacon is no longer detected, the end is determined. Alternatively, the end is detected using the time the information contained in the beacon signal remains. The time that information remains is used by the timer. For example, the controller 212 can serve as a timer to count down the time remaining at the end when the transmitter 206 is enabled.

Thus, if the interference margin β is less than or equal to 1, it will be satisfied and the call will continue. If the interference margin is not met, β becomes greater than one, so that some activity is taken by controller 212. The actions taken include changing different channels so that the spectrum of the satellite terminal 104 is far from the spectrum potentially interfering with the protected equipment. Countermeasures include lowering the power level of satellite terminal 104. If the power cannot be lowered, the satellite terminal controller 212 is able to communicate at lower power levels by waiting for an improved transmission path. The controller 212 is informed that the user must wait until the satellite terminal can successfully communicate with the satellite 102 at a lower power level, such as when the satellite 102 is located above the satellite terminal 104. I will tell you. As the signal path from satellite terminal 104 to satellite 102 changes, the power level required to transmit signals to that satellite 102 changes.

Transmitter 206 alone or transmitter 206, such as receiver 208, may be turned off. The power measurement is preferably repeated periodically. For example, measurements are taken every second while the beacon is detected. This allows satellite terminal 104 to adjust the power variations of transmitter 206 emission as well as positional changes relative to protected site 110.

Other possible operations while in range of the beacon system 112 will limit the length of satellite terminal transmitter 206 use. This allows the satellite terminal 104 transmitter to be simply used for a period of time while not interfering with its protected site 110. More specifically, in the case of RAS integration time, for example, RAS measures during the integration interval. The integration interval will vary, for example it can be a 30 minute period. During that 30 minute integration interval, a short transmission by satellite terminal 104 will cause little damage to measurements by the RAS equipment. In the case of a three-minute transmission by transmitter 206, the margin β decreases to 10% of the previous value of the margin because only one tenth of the energy is input into the RAS band during the integration period. Thus, the satellite control system may allow the satellite terminal to make a short three minute call during a thirty minute integration period. However, if the RAS integration time is as short as three minutes, the margin β can be reduced by any amount, such as 1 / √10, which is 5 dB, assuming sensitivity is proportional to the square root inside the observation for the RAS device. . Thus, the margin β for that satellite terminal can be lowered by 5 dB during the three minute integration time associated with the corresponding threshold value during the 30 minute integration time. Thus, the margin β can be adjusted according to the period of satellite terminal transmission and RAS integration time. By reducing β, that threshold margin β <1 is more easily met.

The beacon system 112 provides the time for which information remains in the beacon signal and the integration time. The beacon signal also provides information identifying the location of the protected site 110. The satellite terminal 104 determines when the beacon system 112 will perform transmission (when the protected site no longer requires protection) and, as described above, margin level over transmission time. Use this information to adjust β.

The operation of the satellite control system 105 for the intelligent beacon management system will now be described with respect to FIG. The satellite control system starts in beacon system 112 and receives control information communicated via satellite terminal 104 and satellite 102 at block 702, which information is subject to protection requests at the protected site. It includes broadcast information of the total time length of the guard period and the remaining time length for the guard period. The satellite terminals 104 measure the beacon power and enter the beacon information sent together. This information is passed from satellite terminal 104 onto satellite 102 and satellite control system 105. This burst is preferably short to avoid roughly interfering with its beacon measurements.

The controller 306 of the satellite control system 105 responds to the information received from the satellite terminals 104 to control signal transmissions by the satellite terminals 104 within the area of the beacon system 112. The beacon area is the transmission range of the beacon system 112. The satellite control system 105 determines the number of satellite terminals 104 in the beacon area by counting the number of terminals that detect the beacon at block 704. The satellite control system 105 also monitors the measured interference at the protected site that forms each user's motion in a call at block 704. The controller 306 determines at the decision block 706 whether the capacity is available when requesting permission to send one or more terminals. If one of the satellite terminals 104 requests permission to transmit, at block 708, the controller 306 determines whether limited or full transmission capacity is available. This is the associated distance between the requesting satellite terminal 104 and the protected site 110 and the estimated power of the transmissions from the satellite terminal 104, and the spectral masks and other operating terminals requesting the satellite terminal 104. And the factors (integration time and time remaining) for the site to be protected 110. The distance can be determined from the signal strength of the beacon signal detected by requesting satellite terminal 104. Alternatively, it is a satellite terminal measured by Doppler measurements from satellite 102 or by global location information and by the location of the protected site 110, as included in the beacon signal. Can be measured from the location of 104.

In response to this information, the control system 105 transmits control parameters, which may be constrained on transmission to the satellite terminal 104 requesting, for example, at block 710. These parameters include the maximum length of call indications and the channels that can be used by the satellite terminal 104, the maximum power per call and the allowable bit rates. The control system 105 may deny access until one or more other terminals 104 have ceased activity. In some cases, the satellite control system 105 may determine that the activity level is too high to transmit a signal to all satellite terminals 104 in the beacon area that it turns off.

When detected at block 706, after determining that a transfer, or transfer request, of the parameters has not occurred, controller 306 determines at block 712 whether the protected site 110 no longer requires protection. . If included, this may be detected by the lack of a beacon signal or by the passage of a protected time interval indicated by the beacon signal. If protection is no longer needed, the controller 306 returns to block 706. At the end of the protection interval, the controller 306 transmits a signal to the satellite terminals 104 to inform the satellite terminals 104 so that they can operate freely. 302 controls to broadcast. In this way, the satellite terminals 104 are intelligently monitored and controlled so as not to interfere with the protected site.

Thus, the satellite terminals 104 operate in a manner that reduces emissions that potentially interfere with the equipment at the protected site. This can be done only by operating at low power levels and / or by changing to a signal that is further away from the operating frequency of the protected site 110 and, if necessary, by disabling transmission by the satellite terminals 104. Can be. The satellite terminals 104 can operate in the presence of a beacon signal in situations such that the satellite terminal 104 does not interfere with the system of the protected device.

Claims (34)

A method of selectively operating a wireless device near a protected site that includes equipment that uses at least intermittent operating frequencies, Detecting a beacon signal; Identifying interference parameters, Controlling the operation of a wireless device to avoid interference with equipment at the protected site, wherein the operation of the wireless device is varied in accordance with identified interference parameters. 2. The method of claim 1, further comprising: determining whether wireless device transmissions tend to interfere with the equipment, and determining what level below which lower transmission power can be used by the wireless device to reduce interference. How to include more. 2. The method of claim 1, further comprising determining what level of interference can be reduced by reducing the duty cycle of wireless device transmission. 4. The method of claim 1, further comprising determining what level of interference can be reduced by changing the frequency channel of wireless device transmission. 2. The method of claim 1 wherein the step of identifying comprises measuring the power of the beacon signal. 2. The method of claim 1, wherein said identifying step comprises receiving information in said beacon signal. 6. The method of claim 5, further comprising transmitting beacon signal information over an uplink that signals to the control system. 2. The method of claim 1, wherein the controlling step includes controlling the wireless device to operate freely when the beacon signal is no longer detected. The method of claim 1, wherein the checking step, Detecting a beacon power factor G, wherein G is approximately equal to power / sensitivity, Calculating α, which is the ratio of the actual interference given to the spectral proximity and the spectral mask and the worst case interference, Calculating interference margin β = μ * G * (Pt / Pm) / α, where μ is the duty cycle, Pt is the instantaneous power of the wireless device transmission, and Pm is the maximum power of the wireless device transmission. The method of claim 9, wherein the controlling step, If the interference margin is β ≦ 1, the call continues; if β> 1, selectively changing the operation of the wireless device. The method of claim 10, wherein the measurement and calculation are repeated periodically to detect changes in beacon signal information. 10. The method of claim 9, wherein the interference margin β is lowered by limiting the time period of transmissions from the wireless device to a portion of the guard period of the protected site. A method of operating a beacon to prevent interference from a wireless device, the method comprising: Determining the start time and length of one cycle while the site is protected, Transmitting a beacon signal including total time and remaining time information; Terminating transmission of the beacon signal at the end of the period. A method of operating a control system to control the operation of a wireless device in a beacon area of a protected site, the method comprising: Receiving beacon signal information and device state information from at least one wireless device in the beacon area; Calculating control parameters for at least one wireless device in the beacon area from the beacon signal information and the device state information, wherein the calculated control parameters are calculated from the wireless device in the beacon area; How to make the interference less than or equal to the threshold. 15. The method of claim 14, further comprising determining the threshold from beacon signal information. 15. The apparatus of claim 14, wherein the calculated control parameters are generated from spectral masks and operating factors for the predicted power of wireless device transmissions and the wireless device transmissions, the operating factors being of voice, video or data applications, Duty cycle, predicted behavior of protected site frequency usage. 15. The method of claim 14, wherein the control system sends prohibition or enforcement instructions to the wireless device. 15. The method of claim 14, wherein if the capacity becomes available at the wireless device, the control system sends enabling instructions to the wireless device. As a control system, A transceiver for transmitting and receiving signals in communication with the wireless device, A controller coupled to the transceiver, the controller receiving information from the wireless device for a beacon signal detected by the wireless device and transmitting operating parameters for the wireless device. 20. The control system of claim 19, wherein the controller calculates the operating parameters and operating factors for the wireless device from predicted transmit powers and spectral masks for transmissions by the wireless device. 20. The control system of claim 19, wherein the control system sends transmission force instructions to the wireless device. As a wireless device, A transceiver circuit and the transceiver circuitry is arranged to receive a beacon signal from a protected site, A controller for coupling the transceiver circuit to selectively control the transceiver circuit responsive to the beacon signal, wherein the transceiver circuit transmissions are detrimental to the protected site caused by transmissions by the wireless device. Wireless device selectively controlled to prevent interference. 23. The wireless device of claim 22 wherein the controller determines whether wireless transmissions tend to interfere with the protected site and determines whether low transmit power can be used to reduce interference. 23. The wireless device of claim 22, wherein the controller determines what level of interference can be reduced by reducing the duty cycle of the wireless device. 23. The wireless device of claim 22 wherein the controller determines which frequency channel is to be changed to reduce interference below. 23. The wireless device of claim 22 wherein the controller measures power of the beacon signal. 23. The wireless device of claim 22 wherein the controller controls the transceiver circuit to transmit the beacon information to control a system. 27. The wireless device of claim 26 wherein the controller controls the wireless device to operate freely when the beacon signal is no longer detected. 23. The wireless device of claim 22, wherein the wireless device controls free operation when the beacon signal is no longer detected. 23. The apparatus of claim 22, wherein the controller calculates a beacon power factor G, which is approximately equal to power / sensitivity, Compute α, the ratio of the worst-case and actual interference given by spectral proximity and spectral mask, Calculate the interference margin β = μ * G * (Pt / Pm) / α, where μ is the duty cycle, Pt is the instantaneous power of the wireless device transmissions, and Pm is the maximum power of the wireless device transmissions. 31. The wireless device of claim 30 wherein the controller continues operation if the interference margin β &lt; = 1 and changes the operation of the wireless device if the interference margin β &gt; 32. The wireless device of claim 31 wherein the measuring and calculating steps are repeated periodically to detect changes. The wireless device, control system, or method according to any one of the preceding claims, wherein the wireless system is a satellite terminal. The wireless device, control system or method according to any one of the preceding claims, wherein said control system is a satellite control system.