Systems and methods for emergency operation of a wireless communication system

In one embodiment, an emergency configuration control device is provided for a communications system that provides wireless RF communication service to a coverage area, wherein the system comprises an RF protection function coupled to at least one power amplifier, protection function configured to disable the power amplifier when the protection function determines that at least one parameter of the power amplifier has deviated outside of an operating specification, the device comprising: an emergency configuration control module executed by a controller, the emergency configuration control module configured to determine when an emergency event is occurring within the coverage area as a function of a first set of input signals; wherein the emergency configuration control module enters phase one operation and inhibits disabling of the power amplifier by the RF protection function and outputs one or more phase one notification signals in response to determining that the emergency event is occurring.

BACKGROUND

A Distributed Antenna System (DAS) typically includes one or more master units that are communicatively coupled with a plurality of remote antenna units. Each remote antenna unit can be coupled directly to one or more of the master units or indirectly via one or more other remote antenna units and/or via one or more intermediary or expansion units. A DAS is typically used to improve the coverage provided by one or more base stations that are coupled to the master units. These base stations can be coupled to the master units via one or more cables or via a wireless connection, for example, using one or more donor antennas. The wireless service provided by the base stations can include commercial cellular service and/or public safety wireless communications.

During emergency situations, public safety responders that arrive at a scene may need to rely on the DAS network at the scene. Often, local regulations require the communications equipment to remain operable to facilitate emergency communications for a specific set of time, for example 90 minutes. However, it is advantageous for the DAS equipment to remain in service beyond such required time, for as long as possible, since each additional minute that service is maintained can be extremely valuable and potentially save additional lives. In contrast with this need, equipment manufactures for electronic equipment are typically focused on incorporated protective circuitry in RF electronics with the purpose of lengthening the service life of the equipment and extending mean time between failure (MTBF) ratings. Equipment self-preservation is implemented by such protective circuitry in order to shut-down equipment and isolate suspected equipment faults or otherwise prevent anomalous operation in order to minimize damage to the equipment. A conflict occurs when DAS equipment-protection circuitry senses a fault condition and deactivates, or at least limits, RF functions or other functions during an emergency situation to deny the public safety responders with access to the communications network they need to properly respond to the event.

For the reasons stated above and for other reasons stated below which will become apparent to those skilled in the art upon reading and understanding the specification, there is a need in the art for systems and methods for emergency operation of a wireless communication system.

SUMMARY

The Embodiments of the present disclosure provide systems and methods for emergency operation of a wireless communication system and will be understood by reading and studying the following specification.

In one embodiment a communications system for providing wireless radio frequency (RF) communication service to a coverage area, the system comprising: a first unit that comprises: downlink circuitry coupled to at least one power amplifier and configured to radiate a downlink radio frequency signal from at least one antenna into the coverage area; uplink circuitry coupled to a low noise amplifier and configured to receive from the at least one antenna an uplink radio frequency signal; an RF protection function coupled to the at least one power amplifier, the RF protection function configured to disable the at least one power amplifier when the RF protection function determines that at least one parameter of the at least one power amplifier has deviated outside of an operating specification; an emergency configuration control module executed by a controller, the emergency configuration control module configured to determine when an emergency event is occurring within the coverage area as a function of a first set of input signals, wherein emergency configuration control module is further configured to enter phase one operation and inhibit disabling of the at least one power amplifier by the RF protection function in response to determining that the emergency event is occurring.

In accordance with common practice, the various described features are not drawn to scale but are drawn to emphasize features relevant to the present disclosure. Reference characters denote like elements throughout figures and text.

DETAILED DESCRIPTION

Embodiments of the present disclosure provide solutions for RF distributed antenna systems and repeater systems that allows the systems to override equipment self-protection functions during emergency conditions in order to enable them to provide full functionality to public safety responders for as long as possible even at the risk of equipment damage.

FIG. 1is block diagram of one exemplary embodiment of a distributed antenna system (DAS)100that comprises an Emergency Configuration Control (ECC) system comprising Emergency Configuration Control Modules (ECCMs) which are distributed through the master unit, remote antenna unit, and expansion units of the DAS100as described herein. Discussed in further detail below, the ECCMs are implemented by controllers within the DAS master unit and remote antenna units and are activated when the DAS is placed into Emergency Mode. When the DAS100is not operating in Emergency Mode, standard fault protection remains in place to respond to and/or mitigate equipment anomalies in order avoid equipment damage. When the DAS100is placed in Emergency Mode, the ECC system is activated and begins to monitor various sensor and status signal inputs. As a function of those inputs, the ECCMs will output control and alarm signals commiserate with a criticality phase that is derived as a function of the sensor and status signal inputs. One potential response from the ECC system is for the ECCM to output control signals that disables equipment protection circuits in the remote antenna units, among other possible responses as further detailed below. With the protection circuits disabled, the remote antenna units will continue to provide communications functions to public safety responders as long as they are physically able to do so, right up to the point of equipment failure. It should be understood that the descriptions provided herein may apply to repeater systems as well as distributed antenna systems and as such repeater systems embodiments incorporating Emergency Configuration Control Modules such as described herein are expressly contemplated as within the scope of this disclose.

As shown inFIG. 1, the DAS100comprises one or more master units110that are communicatively coupled to one or more remote antenna units112via one or more communication links114. In various different embodiments, the communication links114may comprise wireless communication links, cables (i.e. wired communication links), or some combination thereof. As used herein, the term cable is used generically and may refer to either electrical or fiber optic cables, or hybrid cables comprising both electrical conductors and optical fibers. Is should be understood that DAS100may provide wireless telecommunication services to a building, plant, campus, transportation hub, tunnel, or any other type of facility. In some embodiments, the communication links114discussed herein may each operate bidirectionally with downlink and uplink communications carried over the link. It should also be understood, however, that in other embodiments, a communication link114may itself further comprise a pair of links including, for example, an uplink cable for uplink communication, and a downlink cable for downlink communication. Each remote antenna unit112can be communicatively coupled directly to one or more of the master units110or indirectly via one or more other remote antenna units112and/or via one or more intermediary or expansion units113. In some embodiments, DAS100may further include one or more extension units115that are communicatively coupled to a remote antenna unit112to further extend coverage.

Each master unit110is communicatively coupled to one or more base stations140. One or more of the base stations140can be co-located with the respective master units110to which it is coupled (for example, where the base station140is dedicated to providing base station capacity to the DAS100and is coupled to the respective master units110). Also, one or more of the base stations140can be located remotely from the respective master units110to which it is coupled (for example, where the base station140provides base station capacity to an area beyond the coverage area of the DAS100). In this latter case, the master unit110can be coupled to a donor antenna and repeater or bi-directional amplifier in order to wirelessly communicate with the remotely located base station140.

In this exemplary embodiment, the base stations140include one or more base stations that are used to provide public and/or private safety wireless services (for example, wireless communications used by emergency services organizations (such as police, fire and emergency medical services) to prevent or respond to incidents that harm or endanger persons or property. Such base stations are also referred to here as “safety wireless service base stations” or “safety base stations.” The base stations140also can include, in addition to safety base stations, one or more base stations that are used to provide commercial cellular wireless service. Such base stations are also referred to here as “commercial wireless service base stations” or “commercial base stations.”

The base stations140can be coupled to the master units110using a network of attenuators, combiners, splitters, amplifiers, filters, cross-connects, etc., (sometimes referred to collectively as a “point-of-interface” or “POI”). This network can be included in the master units110and/or can be separate from the master units110. This is done so that, in the downlink, the desired set of RF channels output by the base stations140can be extracted, combined, and routed to the appropriate master units110, and so that, in the upstream, the desired set of carriers output by the master units110can be extracted, combined, and routed to the appropriate interface of each base station140. It is to be understood, however, that this is one example and that other embodiments can be implemented in other ways.

As shown inFIG. 1A, in general, each master unit110comprises downlink DAS circuitry111that is configured to receive one or more downlink signals from one or more base stations140. These signals are also referred to here as “base station downlink signals.” Each base station downlink signal includes one or more radio frequency channels used for communicating in the downlink direction with user equipment116(such as tablets or cellular telephone, for example) over the relevant wireless air interface. Typically, each base station downlink signal is received as an analog radio frequency signal, though in some embodiments one or more of the base station signals are received in a digital form (for example, in a digital baseband form complying with the Common Public Radio Interface (“CPRI”) protocol, Open Radio Equipment Interface (“ORI”) protocol, the Open Base Station Standard Initiative (“OBSAI”) protocol, or other protocol). The downlink DAS circuitry111in each master unit110is also configured to generate one or more downlink transport signals derived from one or more base station downlink signals and to transmit one or more downlink transport signals to one or more of the remote antenna units112.

As shown inFIG. 1B, each remote antenna unit112comprises downlink DAS circuitry118that is configured to receive the downlink transport signals transmitted to it from one or more master units110and to use the received downlink transport signals to generate one or more downlink radio frequency signals that are radiated from one or more antennas119associated with that remote antenna unit112for reception by user equipment116. These downlink radio frequency signals are analog radio frequency signals and are also referred to here as “remote downlink radio frequency signals.” Each remote downlink radio frequency signal includes one or more of the downlink radio frequency channels used for communicating with user equipment116over the wireless air interface. In this way, the DAS100increases the coverage area for the downlink capacity provided by the base stations140.

Also, each remote antenna unit112comprises uplink DAS circuitry121that is configured to receive via antenna(s)119one or more uplink radio frequency signals transmitted from the user equipment116. These signals are analog radio frequency signals and are also referred to here as “remote uplink radio frequency signals.” Each uplink radio frequency signal includes one or more radio frequency channels used for communicating in the uplink direction with user equipment116over the relevant wireless air interface. The uplink DAS circuitry121in each remote antenna unit112is also configured to generate one or more uplink transport signals derived from the one or more remote uplink radio frequency signals and to transmit one or more uplink transport signals to one or more of the master units110.

Each master unit110comprises uplink DAS circuitry124that is configured to receive the respective uplink transport signals transmitted to it from one or more remote antenna units112and to use the received uplink transport signals to generate one or more base station uplink radio frequency signals that are provided to the one or more base stations140associated with that master unit110. Typically, this involves, among other things, combining or summing uplink signals received from multiple remote antenna units112in order to produce the base station signal provided to each base station140. Each base station uplink signal includes one or more of the uplink radio frequency channels used for communicating with user equipment116over the wireless air interface. In this way, the DAS100increases the coverage area for the uplink capacity provided by the base stations140.

As shown inFIG. 1C, each expansion unit113comprises downlink DAS circuitry126that is configured to receive the downlink transport signals transmitted to it from the master unit110(or other expansion unit113) and transmits the downlink transport signals to one or more remote antenna units112or other downstream intermediary units113. Each expansion unit113comprises uplink DAS circuitry128that is configured to receive the respective uplink transport signals transmitted to it from one or more remote antenna units112or other downstream intermediary units113, combine or sum the received uplink transport signals, and transmit the combined uplink transport signals upstream to the master unit110or other expansion unit113. In some embodiments, one or more remote antenna units112may be coupled to the one or more master units110via one or more other remote antenna units112(for examples, where the remote antenna units112are coupled together in a daisy chain or ring topology). In such embodiments, an expansion unit113may be implemented using a remote antenna unit112.

As shown inFIG. 1D, each extension unit115may in some embodiments comprises downlink DAS circuitry118that is configured to receive the downlink transport signals transmitted to it from a remote antenna unit112and to use the received downlink transport signals to generate one or more downlink radio frequency signals that are radiated from one or more antennas119associated with that extension unit115for reception by user equipment116. Each downlink radio frequency signal includes one or more of the downlink radio frequency channels used for communicating with user equipment116over the wireless air interface. In this way, the DAS100may even further increase the coverage area for the downlink capacity provided by the base stations140. Each extension unit115may further comprise uplink DAS circuitry121that is configured to receive via antenna(s)119one or more uplink radio frequency signals transmitted from the user equipment116. These signals are analog radio frequency signals and are also referred to here as “uplink radio frequency signals.” Each uplink radio frequency signal includes one or more radio frequency channels used for communicating in the uplink direction with user equipment116over the relevant wireless air interface. The uplink DAS circuitry121in each extension unit115may also be configured to generate one or more uplink transport signals derived from the one or more remote uplink radio frequency signals and to transmit one or more uplink transport signals to the remote antenna unit112to which it is coupled. In some embodiments, the uplink DAS circuitry121in a remote antenna unit112may be further configured to receive the respective uplink transport signals transmitted to it from an extension unit115and to use the received uplink transport signals to generate uplink radio frequency signals that are provided to the master unit110.

The DAS100can use either digital transport, analog transport, or combinations of digital and analog transport for generating and communicating the transport signals between the master units110, the remote antenna units112, and any expansion units113. For the purposes of illustration, some of the embodiments described here are implemented using analog transport over optical cables. However, it is to be understood that other embodiments can be implemented in other ways, for example, in DASs that use other types of analog transport (for example, using other types of cable and/or using analog transport that makes use of frequency shifting), digital transport (for example, where digital samples indicative of the analog base station radio frequency signals and analog remote radio frequency signals are generated and communicated between the master units110and the remote antenna units112), or combinations of analog and digital transport.

Each unit110,112,113,115in the DAS100can also comprises a respective controller130. The controller130is implemented using one or more programmable processors and memory hardware that execute software that is configured to implement the various features described here as being implemented by the controller130. The controller130, the various features described here as being implemented by the controller130, or portions thereof, can be implemented in other ways (for example, in a field programmable gate array (FPGA), application specific integrated circuit (ASIC), etc.).

Each controller130is configured to monitor and control the operation of the associated unit. Each controller130is also configured to send and receive management data over the DAS100. In one embodiment, each unit110,112,113,115in the DAS100also comprises a modem135that is configured to send and receive management data over the DAS100by modulating and demodulating one or more carrier frequencies that are used for the purpose of communicating management data. In some embodiments (for example, where digital transport is used in the DAS), a separate modem135for modulating and demodulating management data is not used and, instead, the management data is combined with the digital DAS transport data before being supplied to the transport transceiver or other physical layer device.

One or more of the units110,112,113,115in the DAS100also comprise an interface150to couple the controller130in that unit110,112,113,115to an operator control panel131that is deployed near that unit110,112,113,115. The interface150is therefore also referred to here as an “OCP interface150.” Is should be understood that each OCP interface150is limited to hardware that relies on manual inputs or interactions from an operator. In some embodiments, other automated equipment (shown at132) may be coupled to an OCP131that senses, measures, or otherwise evaluates physical values like temperature sensors, smoke detectors, and the like. Each such unit110,112,113,115can include an appropriate connector to attach a cable152(also referred to here as an “OCP cable152”) that is used to couple the unit110,112,113,115to the OCP131. In general, each OCP131can be connected to the nearest unit110,112,113,115of the DAS110.

As mentioned above, in addition to potentially providing commercial connectivity to users via consumer bands, DAS110also distributes public safety connectivity coverage and private safety communication coverage. In the exemplary embodiment shown inFIG. 1, the master unit110and each remote unit112may include an Emergency Configuration Control Module (ECCM)120that is configured to selectively override protective circuitry among other potential responses.

FIG. 2is a diagram illustrating the operation of an Emergency Configuration Control Module120which may be incorporated in the DAS100shown inFIG. 1for any other embodiments shown herein.FIG. 3illustrates one example implementation of an Emergency Configuration Control Module120within the context of a remote antenna unit112or an extension unit115.FIG. 3Aillustrates generally one example implementation of an Emergency Configuration Control Module120within the context of a master unit110or expansion unit113. As shown inFIGS. 3 and 3A, the ECCM120receives as inputs, phase one emergency inputs214, phase two emergency inputs224and phase three emergency inputs234. In response to these inputs, the ECCM120may output a combination of notifications and control actions which may include, but are not limited to, disabling and/or adjusting RF Protection Functions310, DAS Notifications330, Device Control Signals332and Operator Notifications334, for example. In some of the embodiments presented herein, the functions and logic attributed herein to the ECCM120for a particular unit may be implemented as code executed by the unit's controller130.

FIG. 3specifically illustrates the implementation of ECCM120within a remote antenna unit112that further comprises an optical transceiver interface (OTRX)305for communicating via optical fiber with the master unit110(or alternatively, with an expansion unit113), a RF power amplifier311, a duplexer312, an antenna port315that is configured to couple the remote antenna unit112to at least one antenna319, a low noise amplifier (LNA)322, and the downlink and uplink DAS circuitry111and124discussed above. In the illustrated embodiments, power amplifier311power amplifies downlink signals to a desired power level and feeds it to antenna319to radiate to user equipment116(not shown inFIG. 3) via duplexer312. It should be understood, however, that the implementation of ECCM120as depicted inFIG. 3and the corresponding description thereof also applies to the implementation of ECCM120within an extension unit115, with one potential difference being that since an extension unit115communicates directly with a remote antenna unit112, that the optical transceiver interface (OTRX)305would be omitted. That is the downlink DAS circuitry111of the remote antenna unit112and extension unit115, and the uplink DAS circuitry124of the remote antenna unit112and extension unit115, may be communicate coupled together by electrical cables or a wireless link.

Uplink radio frequency signals transmitted from user equipment116in the coverage area of the remote antenna unit300are received via the associated antenna(s)119and provided to LNA322, which amplifies the received uplink signals. The RF circuit protection functions310are configured to disable the power amplifier311when it determines that at least one parameter has deviated outside of an operating specification for the power amplifier. In one embodiment, RF Protection Function310comprises protection and control circuits which operate to disable or otherwise control operation of the power amplifier311in order to protect the power amplifiers311from damaged caused by overheating, over current, and other faults, and/or otherwise prevent the transition of wireless RF signals outside predefined operating parameters. It should also be understood that the electrical component protections afforded by RF protection functions310for power amplifier311can also be applied to the LNA322. As such, in the same manner as descried herein for power amplifier311, the ECCM120may output control signals to disable RF protection functions310for LNA322, or otherwise control RF protection functions310, for example, to permit LNA322to operate out of normal RF specification tolerances, reduces gains, and the like.

The emergency configuration control module120becomes activated when the DAS100is turned to Emergency Mode from normal operations mode. Emergency Mode may be initiated either manually by a public safety responder operating a switch (for example, either before or upon entering the coverage area during an emergency) or via another wired or wireless remote control mechanism. For example, Emergency Mode may be initiated through an input entered by an operator (for example, a public safety responder) via one of the OCPs131coupled to the master unit110, a remote antenna unit112, or an expansion unit113. In one embodiment, an emergency mode signal from an OCP131is transmitted to the controller130of the Master Unit110. As opposed to manual activation of Emergency Mode, in some embodiments Emergency Mode may be initiated in response to sensor signals, or changes in the pattern of communications traffic on public service frequencies supported by DAS100. For example, signals from smoke detectors or temperature detectors may be monitored and when smoke and/or emergency temperature thresholds are triggered, and corresponding signal is transmitted to the controller130of the Master Unit110. In other embodiments, an ECCM120of a Master Unit110, Expansion Unit113or Remote Antenna Unit112may monitor the uplink DAS circuitry121for communications traffic on the public safety frequency bands. An increase in such traffic above a nominal threshold would indicate that public safety operators are responding to an event at the facility and the ECCM120of a Master Unit110would be so notified. For any of these examples, the ECCM120of the Master Unit110in turn conveys the emergency mode signal out to the controller130of each of the expansion units113and remote antenna units112of the DAS100.

As shown inFIG. 2, the ECCM120at the Remote Antenna Unit112may enter phase one operation (shown at212) by receiving an emergency mode signal (shown at210), or based on other phase one emergency inputs (shown at214) received by the ECCM120. It should be noted that entry into phase one operation does not imply that the RF circuitry of the Remote Antenna Unit112is overheating or is otherwise failing or about to fail. Instead, entry into phase one operation means that the Remote Antenna Unit112will now operate in a mode where immediate communication service continuity becomes the primary consideration over long term equipment protection.

The phase one emergency inputs214, may include, but are not limited to, control signals from an OCP131, smoke detector signals, temperature sensor signals, public safety channel uplink traffic measurements, and the like. Signals from sensor devices such as smoke detectors and temperature sensors (for example) may comprise either sensor measurements or alarm signals generated by the sensor devices when measurement thresholds are exceeded. In general, the phase one emergency inputs214are the type of inputs that provide an indication that an emergency is occurring at the facility, rather inputs that necessarily indicate anomalous operation of DAS equipment per se. Moreover, ECCM120may consider the phase one emergency inputs214as a function of a combination of the input signals when determining whether to trigger phase one operation. For example, the phase one emergency inputs214may include a temperature input that triggers when a detected temperature in the proximity of a master unit, expansion unit, or remote antenna unit112exceeds 75 deg. C. That trigger, absent any other input trigger, may not be considered sufficient to enter phase one operation. Similarly, a smoke detector trigger absent any other input trigger, may not be considered sufficient to enter phase one operation. However, the combination of a detected temperature that exceeds 75 deg. C. together with a smoke detector trigger may be sufficient to enter phase one operation. Similarly, an increase in public safety channel uplink traffic measurements along may in some implementations be considered sufficient to enter phase one operation, but not in others. However, the combination of a detected increase in public safety channel uplink traffic together with a smoke detector trigger could be defined as sufficient to enter phase one operation.

As discussed above, entry into phase one operation212places the DAS100in a mode where immediate communication service continuity becomes the primary consideration over long term equipment protection. In response, the ECCM120may output one or more phase one emergency outputs216. For example, in one embodiment in response to entering phase one operation212, the ECCM120outputs a control signal that disables RF protection functions310such as power amplifier311protection circuits that would, under non-emergency operation, automatically switch off the power amplifier311in case of sensed overheating, overcurrent, or other fault conditions, for example. In some embodiments, RF protection functions310may be controlled to permit the power amplifier311and other Remote Antenna Unit112circuits to operate out of normal RF specification tolerances, such as with higher flatness, lower rated output power, and so forth, regardless as to whether such operation continues to meet the relevant telecom standards. For example, in one embodiment, error correction for power amplifier311(for example, feed-forward and/or pre-distortion correction) may be switched off in response to a phase one emergency input214from a temperature sensor reaching a certain temperature threshold. The result may degrade communications quality due to slightly higher intermodulation signals (which under normal operation would not be permitted) but has the advantage when operating in emergency mode of saving power consumption to allow a Remote Antenna Unit112to operate at higher temperatures. Similarly, the gain and/or broadcast power of the power amplifier311may be reduced when operating in emergency mode in order to reduce heat generated by the power amplifier311, which may extend the time in which the Remote Antenna Unit112may continue to provide communications at elevated ambient environment temperatures.

In addition to trying to lessen heat dissipated by the power amplifier, in one or more areas of the facility serviced by DAS100, it may be necessary to add functionality and/or to increase the power consumption of electrical components inside the Remote Antenna Unit112slightly (for example, by activating a fan or cooling element such as a Peltier element) to allow operation at elevated ambient temperatures. In one embodiment, during phase one operation, the ECCM120may output device control signals (shown at332) to operate a fan within the Remote Antenna Unit112to operate at maximum fan speed so that the electrical components are working at lower temperature, which would allow continued operation of the Remote Antenna Unit112in a higher allowed ambient temperature. Any potential disadvantage of higher acoustic noise due to the higher fan speed is acceptable in an emergency case. In one embodiment, the ECCM120may control uplink DAS circuitry124to compensate the optical wavelength of uplink transmission to make sure that the optical wavelength is constant at higher temperatures so that communications between the master unit110and remote antenna units112are maintained.

Phase one emergency outputs216may further comprise notification signals. For example, in one embodiment, the ECCM120may output an operator notification (shown at334) to the OCPs131so that public safety responders are made aware of that a Remote Antenna Unit112has entered phase one operation212. In some embodiments, the operator notification output334may comprise a notification to an offsite monitoring and control system (such as an Andrew Integrated Management and Operating System (A.I.M.O.S.), for example) so that system operators may become aware that an emergency condition has been detected at the facility.

In other embodiments, the phase one emergency outputs216may include a DAS notification330to the master unit110indicating that the Remote Antenna Unit112has entered phase one operation212. As mentioned above, a DAS notification330output from a remote antenna unit112may comprise an input to the master unit110's ECCM120to trigger transmission of the emergency mode signal210to other Remote Antenna Units112and/or expansion units113of DAS100. In still other embodiments, raw sensor data from the phase one emergency inputs214may also be communicated in any notifications to the master unit110, OCPs131and/or offsite monitoring and control system.

In contrast to phase one operation212, which is triggered by inputs214indicative of an emergency at the facility, entry into phase two operation220by the ECCM120occurs when an input is received that indicates that events are now causing degradations to the DAS100itself, and those degradations will likely result in an imminent loss of communication services. As illustrated inFIG. 2, entry into phase two operation220may be triggered as a function of a combination of phase two emergency inputs224received by the ECCM120. Examples of phase two emergency inputs224include, but are not limited to, sensor signals indicating unacceptable power temperature readings from the power amplifier311, and/or smoke within the remote antenna unit112itself. Phase two emergency inputs224may also include signal loss measurements to detect increasing signal losses (for example, increasing optical power loss or increases in bit error rates or signal to noise ratios) in traffic carried by the one or more communication links114of the DAS100. Signals from sensor devices such as smoke detectors and temperature sensors (for example) may comprise either sensor measurements or alarm signals generated by the sensor devices when measurement thresholds are exceeded.

As opposed to merely detecting elevated ambient temperatures in the vicinity of the Remote Antenna Unit112, a phase two emergency input224for power amplifier temperature may be triggered when a temperature sensor indicates that the power amplifier311has reached or exceeds its rated service temperature. In other words, the power amplifier311is actively overheating and cannot continue long term continuous operation. Detection of increasing signal losses similarly indicate that equipment is malfunctioning. For example, measurements of signal losses in traffic carried by the one or more communication links114, in excess of acceptance criteria, may be an indication of structural failures or overheating that is compromising the physical integrity of the DAS100, for example.

In response to entering phase two operation222, in one embodiment the ECCM120outputs phase two emergency outputs226which may include critical mode alarms to the OCPs131, offsite monitoring and control system (for example, A.I.M.O.S.), and/or other units of the DAS100to provide warning to the public safety responders that the DAS100is now operating under degraded conditions and that continued reliable communications over DAS100is in jeopardy. In some embodiments, a phase two emergency output226may further include notification comprising an estimate of the life time remaining before service from that remote antenna unit110is lost. Such estimates may be calculated by an algorithm executed by the controller130that correlates PA temperature and/or signal losses to estimated remaining life times based on curves or data from tables, for example. With this estimate, public safety responders may plan their activities with more accurate knowledge regarding how long communications will remain available. Raw sensor data from the phase two emergency inputs224may also be communicated in any of the notifications to the master unit110, OCPs131and/or offsite monitoring and control system.

As with phase one operation, in phase two operation, the ECCM120disables protection functions310in order to override protections that would disable the power amplifier310due to overheating, or operating outside of other design regulator specifications. In some embodiments where the remote antenna unit includes RF power amplifiers or circuitry for commercial frequency bands in addition to the essential public safety band services, ECCM120may switch off the commercial bands allowing the remote antenna unit112to save power consumption and therefore operate at higher temperatures. In one embodiment, the commercial bands may be ranked so that ECCM120may switch off the commercial bands in a staggered manner based on the ranking. In some embodiments, the ECCM120may output device control signals322to deactivate optional, non-critical, equipment (such as WLAN routers, for example) to avoid dissipation of additional unnecessary heat into the room occupied by the remote antenna unit112. Alternatively, other external power consumers controlled or feed by the device control signals322could be switched on such as cameras, and standby sensors (such as smoke and/or heat sensors) that can provide additional information to the public safety responders. In addition, during phase two operations, prioritize monitoring may be activated to limit self-check functions and polling to specific critical characteristic such as power amplifier311temperature and communications channel loss. Moreover, other devices may be adjusted. For example, in one embodiment, a fan rotation speed could be switched to maximum rotation. The resulting sacrifice of acoustic noise limitations due to the higher fan speed would be acceptable in an emergency case.

Transition from phase two operation220to phase three operation230occurs when one or more functions of the DAS100have degraded to the point of failure and at least some communications coverage within the coverage area has been lost. As illustrated inFIG. 2, entry into phase three operation230may be triggered as a function of a combination of phase three emergency inputs234received by the ECCM120. Examples of phase three emergency inputs234include, but are not limited to, reception of a critical alarm from the controller130that the remote antenna unit112is out-of-service (00S), reception of a critical alarm from another DAS110component indicating that the component is out-of-service, or any input indicating that communications traffic has been interrupted. Such alarms may originate from sensors, an OCP131, or another component of the DAS100. Upon entry into phase three operation230, the ECCM120will respond with Phase Three Emergency Outputs236. The ECCM120will output DAS Notifications330and/or Operator Notifications334comprising an out-of-service alarm to notify responders and system operators that the communications system has failed. In some embodiments, the ECCM120may repeatedly check for non-permanent failures like failures of intermittent nature. For example, a battery management system may go out of service when system batteries approach or exceed a certain level temperature, but then resume operation as temperature returns to acceptable levels. In such situations where the DAS100becomes inoperable but then regains operability, the ECCM120can output DAS and/or operator notifications (330,334) to notify responders and system operators that the communications system has recovered and is back to service again. It should be understood that as conditions degrade and operation transitions to phase one operation212, to phase two operation220, and to phase three operation230, that one or more of the alarms, control signals, override signals, notifications, and so forth from the prior phases of operation may be continued all the way through phase three operation230for as long as the controller120and ECCM120remain in operation and able to do so. Moreover, in some embodiments, activation of the immediately prior phase of operation may be a prerequisite to activation of the later phase of operation.

As was mentioned above, utilization of an ECCM120such as described above may be used in conjunction with RF signal repeater systems as well as distributed antenna systems.FIG. 4provides one such example embodiment of a repeater system400comprising a downlink path402that includes a downlink LNA410and a downlink power amplifier411, and an uplink path404that includes an uplink LNA422and an uplink power amplifier420. A first antenna port432is configured to couple the uplink power amplifier420and downlink LNA410to one or more donor antenna(s)430via a first duplexer434. A second antenna port415is configured to couple the uplink LNA422and downlink power amplifier411to one or more coverage antennas419via a second duplexer412. In the illustrated embodiment, power amplifier411power amplifies downlink signals from downlink path402to a desired power level and feeds it to antenna(s)419to radiate to user equipment116(not shown inFIG. 4) via duplexer412. Power amplifier420power amplifies uplink signals from uplink path404to a desired power level and feeds it to antenna(s)430to radiate to network communications equipment (such as wireless network base station(s)140, not shown inFIG. 4) via duplexer434.

The repeater system400further comprises an ECCM420. It should be understood that the description of functions and elements attributed herein to the Emergency Configuration Control Module120for operation within a DAS embodiment (such as DAS100) apply as well to the Emergency Configuration Control Module within a repeater system embodiment (such as the ECCM420of repeater system400). Functions and logic attributed herein to ECCM420may be implemented as code executed by the unit's controller in the same manner as previously discussed.

In one embodiment, ECCM420receives phase one emergency inputs (214), phase two emergency inputs (224), and phase one emergency inputs (234), and responds in the same manner illustrated byFIG. 2to output DAS Notifications330, Device Control Signals332, Op Notifications334, and disabling and/or adjusting RF Protections Functions425. Raw sensor data from inputs214,224or234may be communicated in any of the notifications to the master unit110, OCPs131and/or offsite monitoring and control system.

The RF circuit protection functions425are configured to disable one or both of the power amplifiers411and420when it determines that at least one parameter has deviated outside of an operating specification for the power amplifiers. In the embodiment ofFIG. 4, RF Protection Functions425comprises protection and control circuits which operate to disable or otherwise control operation of the power amplifiers411and420in order to protect the power amplifiers from damaged caused by overheating, over current, and other faults, and/or otherwise prevent the transition of wireless RF signals outside predefined operating parameters. As such, ECCM420is configured to override or otherwise manage RF Protection Functions425affecting both uplink path404and downlink path402. That is, the ECCM420may output a control signal that disables RF protection functions425for power amplifiers411and420that would otherwise automatically switch off the power amplifiers in case of sensed overheating, overcurrent, or other fault conditions. Moreover, RF protection functions425may be controlled to permit the power amplifiers411and420to operate out of normal RF specification tolerances, such as with higher flatness, lower rated output power, and so forth, regardless as to whether such operation continues to meet the relevant telecom standards. Similarly, the gain and/or broadcast power of one or both of the power amplifiers411and420may be reduced when operating in emergency mode in order to reduce heat generated by the power amplifiers, which may extend the time in which the repeater system400may continue to provide communications at elevated ambient environment temperatures. The other functions attributed to ECCM120may equally be applied by ECCM420for repeater system400. It should also be understood that the electrical component protections afforded by RF protection functions425for power amplifiers411and420can also be applied to the LNA410and422. As such, in the same manner as descried for power amplifiers411and420, the ECCM420may output control signals to disable RF protection functions425for LNA410and422, or otherwise control RF protection functions425, for example, to permit LNA410and422to operate out of normal RF specification tolerances, reduces gains, and the like.

EXAMPLE EMBODIMENTS

Example 1 includes a communications system for providing wireless radio frequency (RF) communication service to a coverage area, the system comprising: a first unit that comprises: downlink circuitry coupled to at least one power amplifier and configured to radiate a downlink radio frequency signal from at least one antenna into the coverage area; uplink circuitry coupled to a low noise amplifier and configured to receive from the at least one antenna an uplink radio frequency signal; an RF protection function coupled to the at least one power amplifier, the RF protection function configured to disable the at least one power amplifier when the RF protection function determines that at least one parameter of the at least one power amplifier has deviated outside of an operating specification; an emergency configuration control module executed by a controller, the emergency configuration control module configured to determine when an emergency event is occurring within the coverage area as a function of a first set of input signals, wherein emergency configuration control module is further configured to enter phase one operation and inhibit disabling of the at least one power amplifier by the RF protection function in response to determining that the emergency event is occurring.

Example 2 includes the system of example 1, wherein the emergency configuration control module further outputs one or more phase one notification signals in response to entering phase one operation.

Example 3 includes the system of example 2, the system further comprising: an operator control panel coupled to the first unit, wherein the emergency configuration control module is configured to receive at least one of the first set of input signals from the operator control panel and further configured to transmit at least one of the one or more phase one notification signals to the operator control panel.

Example 4 includes the system of example 2-3, wherein the emergency configuration control module is communicatively coupled by a network to an offsite monitoring and control system located outside of the coverage area, and configured to transmit at least one of the one or more phase one notification signals to the offsite monitoring and control system.

Example 5 includes the system of any of examples 1-4, wherein the first set of input signals comprises one or more of: a signal from a smoke detector; a signal from a temperature sensor; a signal from an operator control panel; and an emergency mode signal.

Example 6 includes the system of any of examples 1-5, wherein the first set of input signals comprises a measurement of uplink communications traffic through the system in a first frequency band.

Example 7 includes the system of any of examples 1-6, wherein the emergency configuration control module further controls the RF protection function to reduce either a signal power, a signal gain, or both, in response to entering phase one operation.

Example 8 includes the system of any of examples 1-7, further comprising: at least one master unit configured to receive a base station downlink radio frequency signal and to transmit a base station uplink radio frequency signal; wherein the first unit comprises a remote antenna unit that is communicatively coupled to the at least one master unit.

Example 9 includes the system of example 8, wherein the emergency configuration control module is comprised in the at least one master unit, in the remote antenna unit, in an extension unit coupled to the remote antenna unit, or in an expansion unit communicatively coupled to the remote antenna unit and the at least one master unit.

Example 10 includes the system of any of examples 8-9, wherein the emergency configuration control module is comprised in the remote antenna unit and a second emergency configuration control module is comprised in the at least one master unit.

Example 11 includes the system of any of examples 1-10, wherein the first unit comprises a repeater system.

Example 12 includes the system of example 11, wherein the first unit is further configured to receive a base station downlink radio frequency signal and to transmit a base station uplink radio frequency signal.

Example 13 includes the system of any of examples 11-12, wherein the at least one power amplifier comprises an uplink power amplifier and a downlink power amplifier; wherein the emergency configuration control module is further configured to inhibit disabling of the uplink power amplifier and the downlink power amplifier in response to entering phase one operation.

Example 14 includes the system of any of examples 1-13, wherein the emergency configuration control module is further configured to determine when operation of the communications system is degraded as a function of a second set of input signals; wherein the emergency configuration control module is further configured to enter phase two operation in response to determining that the communications system is degraded while the emergency event is occurring; and wherein the emergency configuration control module is further configured to override the RF protection function and output one or more phase two notification signals in response to entering phase two operation.

Example 15 includes the system of example 14, wherein the one or more phase two notification signals include a critical mode alarm transmitted to: at least one operator control panel; and an offsite monitoring and control system located outside of the coverage area and communicatively coupled by a network to the emergency configuration control module.

Example 16 includes the system of any of examples 14-15, wherein the one or more phase two notification signals include a system life estimate calculated by the controller.

Example 17 includes the system of any of examples 14-16, wherein the at least one power amplifier comprises a power amplifier for a first frequency band and a second power amplifier for a second frequency band; wherein the emergency configuration control module is further configured to disable the second power amplifier for the second frequency band in response to entering phase two operation.

Example 18 includes the system of any of examples 14-17, wherein the emergency configuration control module is further configured to control the operation of one or more external electrical components in response to entering phase two operation.

Example 19 includes the system of any of examples 14-18, wherein the second set of input signals comprises one or more of: an indication of signal loss; an indication from a smoke detector of smoke within the unit; and an indication of power amplifier temperature.

Example 20 includes the system of any of examples 14-19, wherein the emergency configuration control module is further configured to determine when communications coverage within the coverage area has been at least partially lost as a function of a third set of input signals; wherein the emergency configuration control module is further configured to enter phase three operation in response to determining that communications coverage within the coverage area has been at least partially lost while the emergency event is occurring; and wherein the emergency configuration control module is further configured to output one or more phase three notification signals in response to entering phase three operation; wherein the one or more phase three notification signals include an out of service alarm transmitted to one or both of: at least one operator control panel; and an offsite monitoring and control system located outside of the coverage area and communicatively coupled by a network to the emergency configuration control module.

Example 21 includes an emergency configuration control device for a communications system that provides wireless radio frequency (RF) communication service to a coverage area, wherein the communications system comprises an RF protection function coupled to at least one power amplifier, the RF protection function configured to disable the at least one power amplifier when the RF protection function determines that at least one parameter of the at least one power amplifier has deviated outside of an operating specification, the device comprising: an emergency configuration control module executed by a controller, the emergency configuration control module configured to determine when an emergency event is occurring within the coverage area as a function of a first set of input signals; wherein the emergency configuration control module is further configured to enter phase one operation and inhibit disabling of the at least one power amplifier by the RF protection function and output one or more phase one notification signals in response to determining that the emergency event is occurring.

Example 22 includes the device of example 21, wherein the emergency configuration control module further controls the RF protection function to reduce either a signal power of the at least one power amplifier, a signal gain of the at least one power amplifier, or both, in response to entering phase one operation.

Example 23 includes the device of any of examples 21-22, wherein the emergency configuration control module is further configured to determine when operation of the communications system is degraded as a function of a second set of input signals; wherein the emergency configuration control module is further configured to enter phase two operation in response to determining that the communications system is degraded while the emergency event is occurring; and wherein the emergency configuration control module is further configured to override the RF protection function and output one or more phase two notification signals in response to entering phase two operation.

Example 24 includes the device of any example 23, wherein the one or more phase two notification signals include a system life estimate calculated by the controller.

Example 25 includes the device of any of examples 23-24, wherein the at least one power amplifier comprises a power amplifier for a first frequency band and a second power amplifier for a second frequency band; wherein the emergency configuration control module is further configured to disable the second power amplifier for the second frequency band in response to entering phase two operation.

Example 26 includes the device of any of examples 23-25, wherein the emergency configuration control module is further configured to control the operation of one or more external electrical components in response to entering phase two operation.

Example 27 includes the device of any of examples 23-26, wherein the emergency configuration control module is further configured to determine when communications coverage within the coverage area has been at least partially lost as a function of a third set of input signals; wherein the emergency configuration control module is further configured to enter phase three operation in response to determining that communications coverage within the coverage area has been at least partially lost while the emergency event is occurring; and wherein the emergency configuration control module is further configured to output one or more phase three notification signals in response to entering phase three operation.

Example 28 includes the device of example 27, wherein the one or more phase one notification signals, one or more phase two notification signals, and one or more phase three notification signals are transmitted to at least one of: a master unit of the communication system; at least one operator control panel within the communication system; and an offsite monitoring and control system located outside of the coverage area and communicatively coupled by a network to the emergency configuration control module.

Example 29 includes the device of any of examples 27-28, wherein the first set of input signals comprises one or more of: a signal from a smoke detector; a signal from a temperature sensor; a signal from an operator control panel; an emergency mode signal; and a measurement of uplink communications traffic through the system in a first frequency band; wherein the second set of input signals comprises one or more of: an indication of signal loss; an indication from a smoke detector of smoke within an electrical device of the communications system that houses the at least one power amplifier; and an indication of power amplifier temperature; and wherein the third set of input signals comprises an indication that a communications coverage within the coverage area has been at least partially lost.

Example 30 includes the device of any of examples 21-29, wherein the communication system comprises either a radio frequency distributed antenna system or a radio frequency repeater system.

In various alternative embodiments, system and/or device elements, method steps, or example implementations described throughout this disclosure (such as any of the master units, remote antenna units, expansion units, controllers, circuitry, Emergency Configuration Control Modules, RF protection functions, control units or sub-parts thereof, for example) may be implemented at least in part using one or more computer systems, field programmable gate arrays (FPGAs), or similar devices comprising a processor coupled to a memory and executing code to realize those elements, processes, or examples, said code stored on a non-transient hardware data storage device. Therefore, other embodiments of the present disclosure may include elements comprising program instructions resident on computer readable media which when implemented by such computer systems, enable them to implement the embodiments described herein. As used herein, the term “computer readable media” refers to tangible memory storage devices having non-transient physical forms. Such non-transient physical forms may include computer memory devices, such as but not limited to punch cards, magnetic disk or tape, any optical data storage system, flash read only memory (ROM), non-volatile ROM, programmable ROM (PROM), erasable-programmable ROM (E-PROM), random access memory (RAM), or any other form of permanent, semi-permanent, or temporary memory storage system or device having a physical, tangible form. Program instructions include, but are not limited to computer-executable instructions executed by computer system processors and hardware description languages such as Very High Speed Integrated Circuit (VHSIC) Hardware Description Language (VHDL).

It should be appreciated that other network architectures may be implemented that still functionally operate in the same manner as described in any of the embodiments described herein. It should also be understood that for any of the embodiments described herein, while the communication links connecting master units and remote antenna units may comprise optical fiber, in other embodiments other wired or wireless communication links, or combinations thereof, may be utilized instead of, or in combination with, optical fiber communication links.

As used herein, DAS and repeater system related terms such as “master unit”, “remote unit”, “remote antenna unit”, “expansion unit”, “control unit” and “controller” refer to hardware elements that would be immediately recognized and understood by those of skill in the art of wireless communications and are not used herein as nonce words or nonce terms for the purpose of invoking 35 USC 112(f).