Mobile user system beam and satellite handoff

Radios configured to operate in a satellite-based mobile user system and methods configured to support seamless beam and satellite handoff of such radios are disclosed. A radio may include a receiver, a transmitter, and one or more receiver-exciter in communication with the receiver and the transmitter. The receiver-exciter may include a bi-directional path configured to support radio communications and a receive-only path configured to receive signals on all frequencies utilized by a mobile user system. The radio may further include one or more waveform processor in communication with the receiver-exciter. The waveform processor may be configured to: digitize signals received on all frequencies utilized by the mobile user system; separate the signals into multiple channels; estimate quality measurements for the multiple channels; select a channel from the multiple channels based on the quality measurements; and establish a connection with the mobile user system using the selected channel.

BACKGROUND

Mobile user systems such as the Mobile User Objective System (MUOS) and the like are configured to provide worldwide, multi-service communications capabilities to newer, smaller terminals. Recent studies, however, concluded that MUOS is not operationally effective in providing reliable worldwide Wideband Code Division Multiple Access (WCDMA) communications to tactical users. One of the reasons for this conclusion is that MUOS does not provide the capability for a transparent transfer of communication services as a user transitions between satellite coverage areas and between satellite beams. MUOS breaks the connection between users when the system determines a transition to a new cell is needed, and then reconnects the users. It is noted that this handoff process creates a complete loss of communications.

SUMMARY

In one aspect, embodiments of the inventive concepts disclosed herein are directed to a radio. The radio may include a receiver, a transmitter, and at least one receiver-exciter in communication with the receiver and the transmitter. The at least one receiver-exciter may include a bi-directional path configured to support radio communications and a receive-only path configured to receive signals on all frequencies utilized by a mobile user system. The radio may further include at least one waveform processor in communication with the at least one receiver-exciter. The at least one waveform processor may be configured to: digitize signals received on all frequencies utilized by the mobile user system; separate the signals into a plurality of channels; estimate quality measurements for the plurality of channels; select a channel from the plurality of channels based on the quality measurements; and establish a connection with the mobile user system using the selected channel.

In a further aspect, embodiments of the inventive concepts disclosed herein are directed to a satellite based mobile user system terminal. The satellite based mobile user system terminal may include a receiver, a transmitter, and at least one receiver-exciter in communication with the receiver and the transmitter. The at least one receiver-exciter may include a bi-directional path configured to support radio communications with at least one satellite of the satellite based mobile user system and a receive-only path configured to receive signals on all frequencies utilized by the satellite based mobile user system. The satellite based mobile user system terminal may further include at least one waveform processor in communication with the at least one receiver-exciter. The at least one waveform processor may be configured to: digitize signals received on all frequencies utilized by the satellite based mobile user system; separate the signals into a plurality of channels; estimate quality measurements for the plurality of channels; select a channel from the plurality of channels based on the quality measurements; and establish a connection with the satellite based mobile user system using the selected channel.

In another aspect, embodiments of the inventive concepts disclosed herein are directed to a method. The method may include: providing a bi-directional path to support radio communications with a mobile user system; providing a receive-only path to receive signals on all frequencies utilized by the mobile user system; digitizing signals received on all frequencies utilized by the mobile user system; separating the signals into a plurality of channels; estimating quality measurements for the plurality of channels; selecting a channel from the plurality of channels based on the quality measurements; and establishing a connection with the mobile user system using the selected channel.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the inventive concepts disclosed and claimed herein. The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the inventive concepts and together with the general description, serve to explain the principles and features of the inventive concepts disclosed herein.

DETAILED DESCRIPTION

Reference will now be made in detail to exemplary embodiments of the inventive concepts disclosed herein, examples of which are illustrated in the accompanying drawings.

Embodiments of the inventive concepts disclosed herein are directed to radios configured to operate in a satellite-based mobile user system and methods configured to support seamless beam and satellite handoff of such radios. For purposes of simplicity and clarity, an exemplary ultra high frequency satellite communication system commonly referred to as the Mobile User Objective System (MUOS) will be referenced in the various examples described below. It is to be understood that the references to the MUOS are merely exemplary and are not meant to be limiting. It is contemplated that radios and methods configured in accordance with embodiments of the inventive concepts disclosed herein may be utilized in various other types of satellite-based mobile user systems without departing from the broad scope of the inventive concepts disclosed herein.

It is noted that because the base stations in satellite-based mobile user systems are positioned miles above ground, they typically use very high transmit power and different base stations typically use different frequencies to create separation. A typical terminal device (e.g., a MUOS radio) is configured to listen to one frequency at a time. As the terminal device moves away from a first satellite beam region towards a second satellite beam region, the terminal device has to break its connection with the first satellite beam region, search for the next best channel that can be used, and establish a new connection with the second satellite beam region. This process may be referred to as “break before make,” and it results in loss of communication that may last for several minutes.

Radios configured in accordance with embodiments of the inventive concepts disclosed herein are configured with abilities to listen to more than one frequency at a time, allowing the radios to implement a “make before break” hand off process that can avoid loss of communication. Referring generally toFIG. 1, a block diagram depicting an exemplary radio100configured in accordance with an embodiment of the inventive concepts disclosed herein is shown. The radio100may include a single receiver-exciter (denoted as CRE-A)102configured to support two paths104and106. More specifically, path104(together with analog-to-digital converter (A2D)114and digital-to-analog converter (D2A)120) may be configured to function as a bi-directional path that can support narrowband and wideband (e.g., 1.2 MHz, 5 MHz, and 32 MHz) communications. Path106, on the other hand, may be configured as a receive-only path. The path106may be configured to receive signals within a particular band (e.g., receives signals within a 5 MHz band within the 360-380 MHz range, thus allowing the path106to receive any one of the four channels in the 360-380 MHz range). Alternatively, the path106may operate as a direct path with no filters. The direct path can feed the full bandwidth (which includes multiple channels) received from the analog front end108to the A2D110for digital processing.

During normal operations, path104of CRE-A102may be configured to transmit using a 5 MHz channel bandwidth. Path104of CRE-A102may be communicatively connected to a transmitter, which may utilize a power amplifier130to facilitate the transmission. Path106of CRE-A106may be configured to receive using direct path to support full duplex communication. More specifically, the input to the auxiliary receiver112may come from a multiplexer (not shown), which may have already filtered out everything with the exception of the MUOS receive band (e.g., 340-380 MHz). The input may be provided to the front end108, which then sends the receive band to path106of CRE-A106. Path106may subsequently send the receive band to the A2D110to be processed for waveform reception.

It is noted that even though the entire 40 MHz receive band (360-380 MHz plus the extended receive band 340-360 MHz) is sent to the A2D110, the system may be able to process only 6 out of the 8 MUOS channels due to aliasing. If aliasing is a problem, additional filters (e.g., added to the multiplexer or implemented as a bump in the wire) may be utilized to further limit the bandwidth to be less than or equal to 32 MHz. It is noted that because MUOS will be deployed with only 4 channels (within the 360-380 MHz band) initially, having the abilities to process 6 MUOS channels may be sufficient. It is also contemplated that by selecting a sampling rate greater than 200 MHz and using intermediate frequency (IF) filters that pass 40 MHz can ensure that next generation radios can overcome the aliasing issue and process all 8 MUOS channels and/or 40 MHz waveforms.

FIG. 2is a block diagram depicting an exemplary radio200configured in accordance with an embodiment of the inventive concepts disclosed herein. The configuration of the radio200is similar to that of the radio100, except for that the radio200may include two receiver-exciters (denoted as CRE-A102and CRE-B122). As shown inFIG. 2, both CRE-A102and CRE-B122may include two paths, path104and path106for CRE-A102, and path124and path126for CRE-B122, respectively. Path104of CRE-A102may be configured to transmit using a 5 MHz channel bandwidth and path124of CRE-B122may be configured to receive and support full duplex communication. The input to the auxiliary receiver112may come from a multiplexer (not shown), which may have already filtered out everything with the exception of the MUOS receive band (e.g., 340-380 MHz). The input may be provided to the front end108, which then sends the receive band to path124of CRE-B122. It is noted that path124of CRE-B122may serve effectively as an additional filter to help further reduce noises outside of the MUOS receive band. The output of path124of CRE-B122may then be fed to path106of CRE-A106, which may be configured to operate as described above.

It is noted that CRE-A102and CRE-B122may be implemented using the same hardware, which may help reduce manufacturing cost. However, it is also noted that path126of CRE-B122is not fully utilized in the configuration depicted inFIG. 2. A modified radio300depicted inFIG. 3addresses this concern.

As shown inFIG. 3, one or more filters may be provided to the front end108to limit the bandwidth sent to CRE-B122. The filtered band may then be provided to CRE-B122, where path124of CRE-B122may be configured to help further reduce noises outside of the MUOS receive band before feeding the filtered band to path106of CRE-A106, which may be configured to operate as described above. Path126of CRE-B122may be configured to receive signals within a particular band (e.g., receives signals within a 5 MHz band out of the 32 MHz band) and provide that particular band (which corresponds to a particular channel) to the A2D114to be processed for waveform reception.

It is to be understood that the references made to 5 MHz channels and 32 MHz frequency bands are merely exemplary and are not meant to be limiting. It is also to be understood that radios100,200, and300described above are merely exemplary. It is contemplated that modifications may be made to radios100,200, and300described above without departing from the broad scope of the inventive concepts disclosed herein. It is to be understood that an objective of configuring radios100,200, and300in the manner described above is to provide the radios100,200, and300abilities to continue listening to one base station (or one channel) while negotiating with another base station (or another channel), allowing the radios to establish new connections before breaking existing connections and effectively providing seamless handoff processes. This ability is realized by allowing the radios100,200, and300to receive signals on all MUOS frequencies and use the A2D110to digitize the received signals before they are filtered out (e.g., separated or split) into independent channels by the waveform field-programmable gate array (FPGA)116or one or more general purpose processors (GPPs)118. The independent channels may then be processed in parallel, serial, or a combination thereof.

It is noted that while the radios100,200, and300described above are now equipped with abilities to support seamless handoff processes, the MUOS system (of which the radios100,200, and300are terminal nodes) is required to provide support for it as well. Propitiously, the current MUOS system is already capable of supporting the aforementioned changes to the radios.FIG. 4is a simplified block diagram depicting a MUOS system400. Each satellite participating in the MUOS system400may be configured to support a number of spot beams (e.g.,16spot beams). Each spot beam may have a number of frequencies (e.g., 4 frequencies) each handled by a single Radio Base Station (RBS)402. Multiple RBSs402may be handled by a single Radio Network Controller (RNC)404; multiple RNCs404may be serviced by a single Serving GPRS Support Node (SGSN)406; and multiple SGSNs406may be serviced by a single Gateway GPRS Support Node (GGSN)408. The MUOS system400may also include additional components generally referred to as IP Multimedia Subsystem (IMS)410, which are utilized to support packet networking. It is noted that because the components utilized to form the MUOS system400are well understood by those skilled in the art, detailed explanations of these components are not repeated in the present disclosure.

Also depicted inFIG. 4is a handoff process of a radio412. It is noted that when the radio412is locked on to a frequency, it gets associated with the RBS (e.g., RBS-1) that handles that particular frequency as well as the RNC (e.g., RNC-1), the SGSN (e.g., SGSN-1), and the GGSN along the path414. As the radio412moves away from RBS-1and starts to negotiate with RBS-N handled by the same RNC-1, for example, a local handoff situation is created, which can be handled easily because RNC-1already has the control information needed. Therefore, as long as the radio412has the ability to communicate over multiple frequencies to establish a connection with RBS-N before break off its connection with RBS-1, a seamless handoff can be achieved in this local handoff situation.

FIG. 5depicts a handoff process that crosses RNCs. Suppose the radio412is moving away from RBS-1handled by RNC-1and wants to establish a new connection with RBS-2handled by another RNC (e.g., RNC-M). It is noted that this handoff process may require some additional backend support (e.g., the backend will need to send signals to via both paths414and418during the handoff process), but this backend support can be provided without any structural/architectural changes to the MUOS system400because the components involved are already networked. It is therefore contemplated that as long as the radio412has the ability to communicate over multiple frequencies, a seamless handoff can be achieved when the radio crosses RNCs (or even SGSNs) by coordinating the routing within the MUOS system400.

It has already been shown that radios100,200, and300described above have the abilities to communicate over multiple frequencies. In other words, radios100,200, and300described above can be utilized in a MUOS system400and achieve seamless handoff both locally and across RNCs. It is noted, however, there may still be some additional system-level requirement that needs to be satisfied. For instance, the radios100,200, and300may be required to have parallel multi-channel estimation capabilities to help support seamless handoff. More specifically, a radio configured in accordance with embodiments of the inventive concepts disclosed herein may have to be able to receive the common pilot channel (CPICH) transmitted by every RBS. The radio may then use the CPICH for channel estimation, load balancing, and making measurements needed for handover and base station selection/reselection.

It is noted that radios configured in accordance with embodiments of the inventive concepts disclosed herein do have the abilities to receive the CPICH transmitted by every RBS. More specifically, since radios configured in accordance with embodiments of the inventive concepts disclosed herein can receive signals on all MUOS frequencies, multiple channels are visible to the radios, and these radios can indeed perform simultaneous channel estimation of all visible channels.

For instance, the radio may use quality measurements, such as the Ec/No measurement, of each RBS to determine the best channel to operate on. The Ec/No measurement may be calculated as the received signal code power divided by the total received power (which is equivalent to the received signal strength indicator). Once the best channel is determined, the radio may transition to traditional MUOS processing that permits the radio to log on to the MUOS network and become operational.

Once the radio becomes operational, the radio resource control layer of the radio may be connected to the radio resource control layer of the RNC that the radio is connected to. The RNC may also initiate measurement procedures and periodically send out a measurement control message to the radio and prompt the radio to perform Ec/No measurements of all RBS visible and report back to the RNC. Another technique that the RNC can employ is that it can initiate a periodic reporting cycle where the radio will report Ec/No measurements to the RNC at every specified interval. These periodic measurements of Ec/No can be used by the RNC to determine whether a handoff to a neighboring RBS/RNC is required to maintain the link. It is to be understood that because Ec/No measurement techniques are well understood by those skilled in the art, detailed explanations of these techniques are not repeated in the present disclosure.

Referring now toFIG. 6, an illustration depicting a simple handoff scenario is shown. For illustrative purposes, frequencies ft1and fr1are utilized to indicate uplink and downlink frequencies assigned to RBS-1and frequencies ft2and fr2are utilized to indicate uplink and downlink frequencies assigned to RBS-2, respectively.

With reference toFIG. 6, once a radio (indicated as “Terminal T”) moves from Region A into Region B, the radio will start noticing that frequency fr1is deteriorating. The radio may therefore start to prepare for a handoff. For illustrative purposes, a simplified flow diagram descripting a traditional “break before make” handoff process700is presented inFIG. 7.

AsFIG. 7shows, in a traditional “break before make” handoff process, the radio currently in communication with RBS-1(step702) will first inform the various entities involved of the impending handoff (step704). For instance, the radio may send a “SIP Mobility Event Pending” message to inform all participants that its connectivity is degrading and it has to perform a handoff soon. The radio may then wait for an acknowledgement from the network that all participants have been informed of the mobility event. The radio may then send a “SIP Mobility Event Indicator” message to inform all participants that it is initiating a handoff. Upon receiving an acknowledgement from the network, the radio may start handoff processing.

The radio may start handoff processing by tearing down its voice/data connections (step706). For instance, the radio may deactivate all bearer PDP contexts that have been established with RNC-1. RNC-1may then send a “Radio Bearer Release” message to the radio, which may then acknowledge by sending a “Radio Bearer Release Complete” message to RNC-1. RNC-1may then send a “Radio Link Deletion Request” to RBS-1, which may respond with a “Radio Link Deletion Response” to RNC-1after releasing all resources. The radio may now perform a search to find a new base station to establish connection and detects frequency fr2and potentially other frequencies and informs RNC-1using control channels. Once the search is complete, the radio can send a “MUOS Acquisition Mobility Assistance Request” to RNC-1through RBS-1control channel on ft1. At this point, the radio is still in communication with the original RNC-1, and RNC-1will respond back with a “MUOS Acquisition Mobility Assistance Response” and ask the radio to use frequency pair ft2, fr2.

The radio may now start establishing connection with RNC-1via RBS-2(step708). For example, the radio may send a “Cell Update” to RNC-1to inform the network that it can now be reached via RBS-2. RNC-1may acknowledge with a “Cell Update Confirm”. The radio may then send an “Activate PDP Context Request” to RNC-1and start allocating resources for the new connection with all concerned parties. RNC-1may send a “Radio Link Setup Request” to RBS-2to allocate the required resources to communicate with the radio and respond with a “Radio Link Setup Response”. After allocating the required resources, RBS-2may reply with a “Radio Link Restore Indication” to RNC-1to confirm resource allocation. RNC-1may then send “Radio Bearer Setup Request” to the radio, which may respond with a “Radio Bearer Setup Complete” to RNC-1. RNC-1may respond with an “Activate PDP Context Accept” to acknowledge that the previous PDP context request sent by the radio is completed. The radio may then send a message to the MUOS network to establish a session by sending a “SIP Invite with Replace”. The MUOS network may respond with a “SIP Trying” message and start to set up the required network resources. Upon completion, the MUOS network may respond with a “SIP Bye” message to the radio indicating availability of network resources. The radio may send a “SIP End of Mobility Event Indicator” informing everyone involved that the handoff process is complete and the radio is now available for communication (step710). The network responds with “SIP OK” confirming end of mobility event.

The process illustrated above shows that once the radio tears down its voice/data connections in step706, the radio loses its communication until it re-establishes communication again in step710. As mentioned previously, this loss of communication may last for several minutes.

FIG. 8is a simplified flow diagram descripting a “make before break” handoff process800supported utilizing a radio configured in accordance with the inventive concepts disclosed herein. It is noted that the radio has the ability to estimate the signal strengths of all visible beams at all times. Once the radio enters Region B (with reference toFIG. 6), the radio can detect the presence of frequency fr2. Initially, fr2may be much weaker than fr1but as the radio moves into Region B, fr2will become stronger and fr1will become weaker. Once fr2increases beyond a specific threshold, the radio will determine that fr2is a candidate for handoff and periodically tracks the Ec/No of that channel. As the terminal moves further in to Region B, the radio may start to notice that frequency fr1is deteriorating and the radio may start preparing for a handoff.

AsFIG. 8shows, in a “make before break” handoff process, the radio currently in communication with RBS-1(step802) will inform the various entities involved of the impending handoff (step804). For instance, the radio may send a “SIP Mobility Event Pending” Message to inform all participants that its connectivity is degrading and it has to perform a handoff soon. The radio may then wait for an acknowledgement from the network that all participants have been informed of the mobility event. The radio may then send a “SIP Mobility Event Indicator” message to inform all participants that it is initiating a handoff. Upon receiving an acknowledgement from the network, the radio may start handoff processing. It is noted that the original connection through RBS-1is still active during this period.

The radio may start handoff processing by establishing a new connection (step806). For instance, the radio may send a “MUOS Acquisition Mobility Assistance Request” to RNC-1through RBS-1. RNC-1may respond back with “MUOS Acquisition Mobility Assistance Response” asking the radio to use frequency pair ft2, fr2. Now the frequency pair ft2, fr2can be associated with a different RBS connected to: 1) the same RNC on the same satellite, 2) a different RBS connected to a different RNC on the same satellite, or 3) a different RBS connected to a different RNC on a different satellite (depending on the movement of the radio). This is agnostic to the terminal and can be handled by the MUOS infrastructure (as previously mentioned).

Subsequently, the radio may lock on RBS-2and start establishing connection with RNC-1. The radio may then send an “Activate PDP Context Request” to RNC-1via RBS-2and start allocating resources for the new connection with all concerned parties. RNC-1may then send a “Radio Link Setup Request” to RBS-2to allocate the required resources to communicate with T and responds with “Radio Link Setup Response”. After allocating the required resources, RBS-2may reply with a “Radio Link Restore Indication” to RNC-1to confirm resource allocation. RNC-1may then send a “Radio Bearer Setup Request” to the radio via ft2. The radio may respond with “Radio Bearer Setup Complete” to RNC-1via fr2. RNC-1may then respond with an “Activate PDP Context Accept” to acknowledge that the previous PDP context request sent by the radio is completed. At this point, the radio can communicate with RNC-1via RBS-1and RBS-2. From now on RNC-1will send information to the radio via RBS-1and RBS-2.

The radio may then start to re-establish communication through the new connection (step808). For instance, the radio may send a message to the MUOS network via RBS-2to establish a session by sending “SIP Invite with Replace”. The MUOS network may respond via RBS-2with a “SIP Trying” and starts setting up the required network resources. Upon completion, the MUOS network may respond with a “SIP Bye” message to the radio indicating availability of network resources.

The radio may now start deactivating all bearer PDP context established with RNC-1via RBS-1(step810). RNC-1may then send a “Radio Bearer Release” message to T via RBS-1. The radio may acknowledge by sending a “Radio Bearer Release Complete” to RNC-1via RBS-1. RNC-1may send a “Radio Link Deletion Request” to RBS-1. RBS-1may respond with a “Radio Link Deletion Response” to RNC-1after releasing all resources. The radio may then send a “SIP End of Mobility Event Indicator” informing everyone involved that the handoff process is complete and terminal T is now available for communication. The network may respond with “SIP OK” confirming end of mobility event.

It is noted that the process illustrated inFIG. 8shows that the radio is able to maintains its communication (e.g., the radio is able to receive) throughout the entire handoff process. The problems associated with loss of communication in a traditional “break before make” handoff process can be effectively avoided.

It is also noted that the “make before break” handoff process depicted inFIG. 8requires the radio to communicate via two RBSs with the MUOS network during the handoff process. Each of the radios100,200, and300shown inFIGS. 1, 2, and 3, however, has just a single transmitter path. It is contemplated that there are at least two options of sharing the single transmitter path. One option is to communicate to RBS-1and RBS-2using the 5 MHz IF filter path during transmit. Using this option may incur a tune time penalty during every switch. An alternative option is to communicate to RBS-1and RBS-2using the 32 MHz IF filter path during transmit. Using this option may avoid the analog tuning because the filter is wide enough to enable communication with multiple channels by digitally shifting the transmitter (e.g., using NCO offset) within the 32 MHz window. It is contemplated that these two options presented here are merely exemplary and are not meant to be limiting. It is to be understood that other options may be made available (including the option of using additional transmitters) without departing from the broad scope of the inventive concepts disclosed herein.

It is also to be understood that the abilities to communicate on two or more MUOS channels simultaneously may be limited by resources and transmit duty cycles of the FPGAs116utilized by the radios100,200, and300.FIG. 9is a simplified block diagram depicting an exemplary FPGA116that may be utilized to support operations of the radios100,200, and300.

Although recent advances in FPGA technology have dramatically increased the ability to process high sample rate signals, it is still a challenge to perform multichannel signal processing without increasing FPGA resources several-fold. However, FPGA-based MUOS Rx channel filtering can be accomplished in multiple stages, at multiple (intermediate) sampling rates so that all high-clock rate clock processing can be kept relatively simple (and the need for duplication of FPGA resources kept at a minimum), while moving more complicated processing (e.g., longer FIR filters) to lower sampling rates, where FPGA resources can be time-division multiplexed (TDM), rather than parallelized. Within the waveform itself, detection of a CPICH channel utilizes about 30% of total MUOS waveform FPGA resources, including logic shared with other receiver functions. Although some of this would have to be duplicated to implement simultaneous multi-channel detection, due to the relatively low baseband sample rate, much of it could be accomplished in a TDM fashion, similar to the Rx frontend signal processing operations. On the uplink (Tx) side, processing resources within the waveform occupy about 18% of the total; however, given the relatively low processing rates, there is an opportunity for time division multiplexing to realize some savings. Finally, in the Tx frontend, as in the Rx frontend, multi-rate signal processing can be employed to keep resource utilizations within reasonable bounds.

As will be appreciated from the above, radios and methods configured in accordance with embodiments of the inventive concepts disclosed herein allows for seamless handoff processing without loss of communication. It may also be appreciated that because radios configured in accordance with embodiments of the inventive concepts disclosed herein can implement a software defined architecture, physical layer processing may be implemented independent from, and in parallel to, the rest of the MUOS waveform processing. Because the higher layer software components may be abstracted away from the other computer software configuration items they depend on, changes to the radio architecture may be made seamlessly with respect to the rest of the radio (both in terms of software and hardware), therefore providing additional flexibilities for controlling radios configured in accordance with embodiments of the inventive concepts disclosed herein.

It is contemplated that radios configured in accordance with embodiments of the inventive concepts disclosed herein may provide additional capabilities unsupported by typical terminal devices (radios) that are configured to listen to one frequency at a time. For instance, radios configured in accordance with embodiments of the inventive concepts disclosed herein may be permitted to participate in multiple call groups simultaneously (both active and emission). Radios configured in accordance with embodiments of the inventive concepts disclosed herein may also address one of the complaints about current MUOS waveform, which is the lack of the knowledge that a handoff is in progress. From the perspective of a user, all that is known currently is that connectivity is lost with certain individuals. This lack of knowledge can be addressed using a special beep followed by an optional audible message (e.g., “Handoff: User1, User2”). The message may also be indicated on a human machine interface and/or various other types of control interfaces. These indications can also define the type of handoff (e.g., traditional or seamless) so that the other participants know that if a seamless handoff is in progress then the user can receive everything going on and can transmit back at a slower rate as they have to share the transmitter.

Radios configured in accordance with embodiments of the inventive concepts disclosed herein may also support a more proactive rectification of potential connectivity issues. More specifically, since a radio configured in accordance with embodiments of the inventive concepts disclosed herein is able to track all visible MUOS downlinks, the radio can provide a proactive means to monitor beam carriers (e.g., SA-WCDMA or spectrally adaptive wideband code division multiple access beam carriers) to prevent extended outages for deployed users. It is contemplated that the beam carrier status can be queried from the local human machine interface or over the air, allowing the network to maintain an active map of network connectivity status. MUOS network managers may assess and report on SA-WCDMA satellite beam carrier availability by querying the terminal periodically. The MUOS network managers may send new configurations to the radio to rectify connectivity issues proactively rather than reactively.

It is contemplated that radios configured in accordance with embodiments of the inventive concepts disclosed herein may be install on various types of mobile platforms and/or vehicles, including land vehicles, watercraft (e.g., ships, boats), aircraft, and spacecraft.

It is believed that the inventive concepts disclosed herein and many of their attendant advantages will be understood by the foregoing description, and it will be apparent that various changes may be made in the form, construction, and arrangement of the components thereof without departing from the broad scope of the inventive concepts or without sacrificing all of their material advantages. The form herein before described being merely an explanatory embodiment thereof, it is the intention of the following claims to encompass and include such changes.