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Original Publication Date: 2015-Jul-22
Included in the Prior Art Database: 2015-Jul-22
Document File: 4 page(s) / 150K

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Szyszka, Grzegorz: INVENTOR [+2]


First Responder(FR) in emergency situation hits emergency button while the channel(conventional) or talkgroup(trunking) is being occupied(0) Subscriber sends Call request to the system: In trunking using Control Channel In conventional, using first available channel known by scanning process, containing call details ? at least call priority and channel number on which FR wants to talk on In response System transmits Interrupt Request on occupied channel, so all the listening subscribers engaged in a call receive Interrupt Request Subscriber that is in proximity to transmitting one, forwards Interrupt Request using short range type of communication(BT/WiFi/wired etc.) Sourcing subscriber ends transmission System accepts call request and sends Call Grant accordingly The FR in emergency is able to communicate Note, that the collaborative device my be also using different RAN ? like LTE and may not be engaged in a call at all. BB network may be used to deliver Interrupt Req to proxy device.

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by Grzegorz Szyszka, Pawel Jurzak

Motorola Solutions, Inc.



Most Land Mobile Radio (LMR) mobile devices are half-duplex in hardware design dictated by economics. A half-duplex mobile radio, by definition, is not receiving when transmitting and vice versa. It limits communication system capabilities as mobile radio is deaf for system requests when transmitting. It is difficult, for example, to deliver signal quality information feedback on time or inhibit transmitting radio remotely.

One of the most critical communication system functionality is ability to dynamically reallocate resources to adjust to alternating environment. Such a resource is for example radio communication channel. It is valuable resource often being system bottleneck.

When a high priority communication requests radio channel that is currently in use, due to lack of availability of other channels or due to audience attached to that channel, system needs to request half-duplex transmitting mobile radio to stop. If this does not happen, then two transmitting radio devices on the same radio channel may lead to audio contention for both sourcing users.

To overcome this problem we propose a proxy device, which when in proximity to transmitting mobile radio, it delivers system requests to transmitting device via one of well known short range type of communication, either wired or wireless.

The proxy mobile device may be one of the subscribers involved in group or individual communication sourced by a transmitting mobile radio, or it may be other one. Depending on the type of the system communication scheme it may take many forms and variations. For example, the system to proxy device communication may make use of the same Radio Access Technology (RAT) as transmitting mobile radio or different one, in the same Radio Access Network (RAN) or in different one.



In a radio communication system channels are valuable and it is important to manage its usage efficiently as its number is very limited.

When mobile radio is transmitting it may be important to interrupt it, for instance when another user needs to start an emergency call on the same channel.

Inhibiting transmitting half-duplex mobile radio, commonly used today, may be difficult as such mobile radio cannot transmit and receive a signal simultaneously.

The above problem exists in both conventional and trunked FDMA systems like P25 Phase 1 and DMR systems Tier I and II.


When high priority call is going to be started and channel is busy radios sends the transmit inhibit command to mobile devices in proximity to transmitting device which conveys it to the sourcing device via short range communication protocol (Bluetooth, WiFi, NFC, Zigbee etc), or via wired connection.  Such a proxy can be a mobile radio installed in a car or portable device that is carried by the same user or different who is close to one that is sourcing media.

The transmit inh...