GB2532863A - Integration of LMR and IP networks - Google Patents

Abstract

A method of operating a router 75 in a multi bearer radio system having a LMR wireless bearer and an IP wireless bearer. Device data is established in the router having a LMR ID and IP address for a plurality of multi bearer devices 70 in the system. Site data is also established in the router having an IP address for each of a plurality of LMR bearer base stations 74 in the system and an IP address for each of a plurality of IP bearer base stations 71 in the system. The site data may include frequency and mode for each of the LMR bearer base stations. Device data may include a talk group ID for one or more of the multi bearer devices. A trunked radio is also disclosed; the trunked radio system having a control channel base station for sending and receiving control messages to and from users of a first LMR base station network and a second cellular IP network base station network, the router mapping between the LMR and IP message protocols.

Description

Intellectual Property Office Application No. GII1518031.8 RTM Date:21 March 2016 The following terms are registered trade marks and should be read as such wherever they occur in this document: LTE pg. I, 3, 8 & 26 3GPP pg. 3 & 8 WiFi Pg. 3 Intellectual Property Office is an operating name of the Patent Office www.gov.uk /ipo IN'I'EGR 4R ANDNETWORKS

HUD OF THE INVENTION

This invention relates to integration of services between a land mobile radio {LMR) communications system and other wireless technology such as cellular that earl offer a multi bearer term nal the relatively high data rates needed to, support an IP path. in particular the invention relates to architectures which use a multi bearer router in either tracked or conventional LMR systems.

BACKGROUND TO M IN 'N

Public safety agencies around the world typically use narrow band, LIVIR technologies such as P25 to communicate voice Miamian and some data traffic.

characteristics of this technology are long range a gh quality -e, Today, Public Safety is considering the use of new technologies, such as LTE, capable of high rate data enabling mobile data applications. 'This form of technology is relatively short range pared to relatively narrow band technologies. In a move to capture the benefit of both nologies, methods of integration are lacing considered.

Typically, LMR systems are deployed, over wide areas where pibli saf safety operation is expected including both populated and unpopulated areas. Typically, cellular systems are deployed over populated areas or areas where revenue can be generated through user traffic. There are areas whore LMR exists but no cellular. There are areas where cellular exists but no LMR,1 here are areas where both LMR and cellular exist. Historically there have been innovations that seek to selectively communicate calls over either cellular or LAIR depending upon which bearer is available.

LMR s typically exist in two. The first is referred tows conventional. In this configuration a radio channel is used by a group of terminal devices where the communication is conducted by a repeater that is typically located on a physically high, site. The user of he terminal will typically make a manual choice of eh number through choosing that channel via a selection, knob on the terminal. Upon pressing a push to talk button on that terminal, the voice is then received by any other terminal that is configured to listen to that channel. In its simplest form, any terminal listening to the channel will umnute. This is one way of creating group communications.

Still considering conventional col municatiCns, a group can also be created acct? a group identity. The group identity ally a specific number that identifies the group. This identity is sent'along with the voice information and now any terminal that is 10 both listening to the channel and a member of this group will unmute.

The other form of system typically' used in LMR is trunked. In this case, there is typi ally one control channel and several traffic channels. In effect, a thanked system is a centrally controlled network or franked controller. All terminals not in a voice call will listen to the control channel. If a call is, initiated then they are sent era a ratfin, ehanncl. Any trunked, terminal wishing to access the network must first register with tl e' netu,o represents a form of security to ensure the terminal is permitted on he network. Registration normally takes place at switch on of the terminal or when he terminal enters coverage of the control channel. All trunked terminals must register, 21) Following registration, all nked terminals must the * citify which groups they are a part of This is required so that if a call for that group is initiated then all terminals in that group can be sent to the correct traffic channel. This group information (referred to as group'affiliation) is knowledge held by the trunked controller.

Millar problem exists in the case of conventional radio wherein the managemet groups remains a key issue seeking to design an integrated solutim and 11'. Key to operation is the management of groups. Here we describe the management of groups through the interpretation of signalling and establishment of optimal, routes required to maintain call quality and seamless connectivity.

tons are required that integrate LMR RE channels and IP capable bearers in such a way th=ata user is unaware cnf the communication bearer being used. In other words, is appears to function as a normal LMR radio whether conventional or trunk ed..

attempts to enable LMR across a cellular network generally selects between an MR k or a normal cellular call, In other words, the protocols ch path are different and only one path is chosen at any time. In some cases LMR is described in the context of tunnelling LMR information through an IP pipe. A key problem exists to the management of control information, path set up and seamless connectivity. rpretation of signalling and establishment of optimal routes are required to maintain, call quality and seamless connectivity.

One approach that has been used in the past is a gateway between LMR and llular.

Methods of this type are subject to -a number of backs including; a mismatch.af audio quality on either side, an incompatible feature set on either side and loss of b ty to establish end to end encryption.

The first bearer is LMR and may APCO 25), Tetra, D. ( )_ital Mobile Ri) or generally any form of relativelyarrow band protocol; The second hear r may be LTE (3GPP Long Term Evolution) or Will or generally any form of wireless bearer capable of relatively high data rates to communicate II packets. 'En an example system P25 is used as the LMR protocol, Other bearers may be present and participate.

Typically in an I IR network a channel ne assigned to a call and the mobile end point of that call is an LMR terminal with a unique ID. "rypically in an IP network over cellular the channel is shared by many mobile end points such as smart devices which have IP addresses. By convening these technologies we sEnall associate the ID of an LMR terminal with an IP address.

An LMR system is also typically Frequency Division Multiple Access (TDIVIA) or Time Division Multiple Access (TDMA). A channel can be defined as either, a frequency, frequency pair or line slot on a frequency or frequency pair.

SUN R OF THE INVENTION

an object venation to,enable into ration of LMR and IP c SS communi ation systems. Integration typically'requirest ing of:signals on the correct path depending upon the status of multi bearer terminat group membership, VOice caltassignthent, or ether signalling niefiSageS required for normal operatton.

In one aspect the hod of operati t',. a router in a multi hearer and an IP wireless bearer. Device data is radio system having an LMR wire established in the router having IR ID and an IP address the each of a plurality of multi be a er devir:cs in the system. >te data is also established in the router having an IP address for arch of a pl rality of LP IR bearer base stations in the system and an IP address for eh of a plurality of IP bearer base stations in the system.

The device data preferably includes a talk group ID for one the multi bearer devices. In a flu nked embodiment the site data includes an IP address 0 ' one or more [MR base stations which provide an LMR control channel.

In another aspect the invention resides iti a method of group cost munic multi bearer devices in a conventional LMR system. LIVIR ID, group ID and IP address information are received from the multi bearer devices, and stored in a router. Group ID and IP address information are received from traffic channel base stations in the system, and stored in the router. Group communications can then be routed between multi bearer devices in a common group according to the IP addresses of base stations which serve the multi bearer devices in the group.

Preferably the router identifies the. P addresses of the base stations tinvugf IP roadcast reports containing frequency of operation and mode.

In a further aspect the invention resides in a method of gistration in a trusted LIVIR 5 system. Initiating an LMR communication using a multi-bearer device capable of both LMR. and IP communication; receiving broadcast information detailing the identification stem including the identity of a control channel base station, using said broadcast information to establish a header packet to enable communication to the contra! ei base station, transmitting said header and LAIR registration content from the multi-bearer device over an IP path to a router, transmitting identifying information from.

base station in the system to the router, receiving said header and IMR. registration i the multi-bearer device at the router, using the identifying information from each base station and routing LMR registration to the base station serving the multi bearer device, transmitting said LMR registration. from the receiving base station to a franked controlla r, r ceiving a inked controller at the base rating the registration response to the router, and receiving registration response at the truusked router and transmitting to the multi-bearer device.

Preferably he header is established through LIVIR broadcast information including the RFSS System Broadcast and Network Broadcast. The router also identifies the IP address he control char.: el base station by receiving broadcast information regardina frequency of operation and mode of the station encapsulated in an IP packet.

In another aspect the invention resides in a ttainked radio communication system for users having =radio equipment which provides both LMR and IP capability. The system includes a first network of base stations which provide LMR services to the users, having a control channel base station and a trunking controller, and a second network of base stations which provide cellular IP services to the users, having a router containing a table IR identities and corresponding °1P addresses. The control channel base station sends and receives control messages to and from users of the system through the first network, and sends and receives control messages to and from users of the system through the second network, using the router fbr mapping between LMR and IP message protocols. The control messages typically include requests and responses relating to registration, group affiliation and call setup.

voting process, messages fioi e sect to a base station serving the user the first network, and also to a base station serving the user in the second network, and then from said base station in the second network via the router to said base station in the first network, In a handover process messa via a base station serving the user in the first network, and also via the router to a base: st anon serving the user in the 10 second network, vention resides in a conventional radio ex unicat r users haying radio equipment which provides both LMR and IP capability. The system includes a first network of traffic channel base stations which provide I,MR services to the users" and a second network or base stations which ptovide cellular IP services to the users, haying a router containing a table of LNIR identities and corresponding IP addresses. The traffic channel base stations send and receive messages to and from users of the system throuth the first network, and to and from users of the in through the second network, using the router for mapping between LMR and IP 20 message protocols.

1141 FIGURES refereed embodiments of the iivention will be described with respect to accompanying drawings, of which: Figure 1 is an integrated LMR and IP communication syst Figure 2 a multi bearer router MBR.

Figure 3 an overview of a tanked system containing voters.

Figure 4 shows a possible implementation of a multi bearer terminal.

Figure 5 shows Network Broadcast Information and determining ID e 6 a sequence diagram illustrating the broadcast and reception of network 7 a seouence diagram showing a registration process via RE sequence diagram showing a process of registration via IP using a established by RF reception.

sequence diagram showing a process of registratiot sequence diagram showing a process for Group xffrliat on via IZF.

Figure 11 a sequence diagram showing a process for group affiliation re 12 a sequence diagram showing a process for group affiliation via TP.

Figure 13 a sequence diagram showing a process for establishing a voice cal a RF.

Figure 14 a sequence diagram showing as process for establishing a voice ea via IP when the terminal is registered.

Figure 15 a sequence diagram showing a process for establishing -Mee call via IP when the terminalis registered.

Figure 16 an illustration of Uplink voice communication using both paths Figure 17 an illustration of Downlink voice communication using both pat Figure 18 a flow diagram describing the operation of the application associated with tine terminal.

Figure I9A&B a flow diagram illustrating operation ked ulti-Bearer pv outer.

e 2 3,atn example table showing routing information, Figure 21 a flow diagram showing the initiation of multiple P25 Bows from a Figure 22. a flow diagram showing the operation of tltiple P25 flov e 23 a sequence diagram showing the establishment of for handever.

Figure 24 a flow diagram ustratin mac,. to handover.

Figure 25 shows informaion flow in dow, Figure 26 a flow diagram showing the operation, of the splitter re 27 a method of voting at the multi bearer terminal Figure 28 a system diagram illustrating the conventional multi bearer router.

Figure 29 a sequence diagram illustrating conventional smart device registration.

Figure 30 a sequence diagram showing automatic;router configuration Figure 31 a sequence diagram showing flow of conventional uplink voice packets, Figure 32 a sequence diagram showing flow of conventional downlink voice packets.

Figure 33 a sample Identity table for conventional radio ease Figure 34 a sample contiextional Routing Table Figure 35A&B a flow diagram for the conventional router.

Figure 36 a flow diagram illustration uplink communication.

Figure 37 a system illustration of downlink communication Figure 38 a flow diagram of splitter operation Figure 39 a flow diagram showing downlink stream selection at multi-bearer hub,

DES RIPTION OF PREFERRED EMBODIMENTS

Referring the drawings it will be reci d the b 'o, may be performed in a variety of ways using a number of platforms n 11,MR information across LMR RF channel and through an IP capable network, 'Fran and conventional APCO P25 are described as the LMR systems in this example, In general Mons any form of LMR could apply including Terrestrial 'Caulked Radio (TETRA), Opensky, NetworkFirst, Enhanced Digital Access Communications System (EDACS) and Digital Mobile Radio (DMR). Further, the IP capable platform may be any data capable standard which can deliver relatively high data rates to enable IP communications. Examples include 3GPP standards such as LTE as well as other standards such as 3GPP2, WiMax and WLAN.

Figure I illustrates the main aomponents of a system that integrates LMR and cellular. A multi-bearer terminal 70 includes a normal P25 terminal and an LTE (or cellular) 30 terminal connected via a processing hub capable of proCessing information between these units. The multi-bearer device 70 is within the coverage area of a P25 sue 74 and a dband IP site In this system all multi-bearer ternaanals have an IP address which becomes associated with an 1 MR ID of the P25 tet Mina! in a multi bearer router multi-bearer device capable of trunked P25 operant). ither standard P25 RE coverage or through an IP path which in this case is facilitated through a cellular connection. The multi hearer device pan send LAIR inform ution via standard P25 RE or through the IP path over cellular or via both. Other P25 terminals 76 and 77 or multi bearer terminals sv111 alsn usually be present.

A voterisplitter 101 is typically located withinabase: station associated with site 74, and apable of either receiving and selecting between multiple uplink paths. or is capable of o send information via multiple paths on the downlink. The voter can be implemented m a number or locations. Further, the operation of the base station is oiled by a P25 trunked controller which forms of the LMR network 78, and may be used for either control channel or traffic channel operation. The voter is capable of accepting multiple IP or RE input although only one ILir artd one IP pipe are scrilued here.

carer router 75 in Figure I he xnru provide various functions, enabled by soLtura re functions include Figure 2 shows the s contains 'a processor ant memory instructions and data which are stored in the memory, intenance of a routing table 61, registration 62 of multi bearer terminals 70, routing 63 of message packets b 1 1,MR and IP networks, and configuration 64 runctions. Respective interfaces 65 and 66 are provided for connection to the IMR and IP networks. A further interface 67 may be provided for manual configuration of the router. 25 A detector 68 determines whether an incoming message is in an LMR or IP protocol.

3 shows ntsof a trunked P25 system, Base station 201 represents a channel in the trunked system and contains a voter 101 which is capable of ssages via either a standard RE path, identified as RF channel CCI or 0 through an IP path identified as IP channel IPCC1. Both paths enter the v and messages are selected to pass on to the P25 trunked controller 79, Conversely the trunked controller may send messages to r 101 which creates copies of each message to send over either CCI or Wc.C1.

The P25 trunk controller traffic to those available contains a vote controller 79 is a cerium point through which all blanked calls pass. The able to control other base stations for the purpose of allocating user Base stations 202 and 203 represent examples of base stations Add typically be present at the same site 74. Each base station 302 and 103 respectively which are able to receive traffic either RE and IP paths. In the case of base station 202, these channels are identified as RE Channel TCH1 and IP channel IPTCH I. On the uplink the voter 102 will select ssaczes between each path and on the downlink it can receive messages front another source, and repeat that on' oth TCH I and EPTC111 on unlink.

02 is sent' to the P25 true# ed controller and The output o he voter are winning packet 15 may be onto another base station or end po traffic is either repeated over R ither bearer n eft led at that point.

e 4 shows one possible realisation of the multi-bearer device 70, or MB R. In this case a standard P25 terminal 400 is connected via Bleetooth to a smart device which has a special. application 404 designed to pair with the P25.rminal and preferentially process messages from the terminal. In this case a standard microphone 402 is also attached to the terminal. The multi-bearer hub can he realised in a number of ways using a number of standard interfaces including WLAN. Other examples might include using a smart microphone which pairs with the smart device. Another example may be a mobile station which uses a standard serial port to connect with a suitable processing platform that may be a smart device. A smart device containing a software P25 terminal might also be used.

e 5 shows informati s typically broadcast witlu a I25 syste P25 system, the following messages are broadcast over RE by the control -&mei CCI via base station 201. A Network System Broadcast message (NET SYS BC and Radio Frequency Subsystem Broadcast (RITSS STS BCST) are broadcast by the co;ntrol channel.

her they give a receiving 'nal all the formation needed to uniquely identify base station from which the control channel broadcast is occurring. Identification is ically facilitated through combination of the Wide Area Communications Network ID (WACNID), System ID, Rh Sub system ID Site ID and Channel, Typically a terminal would respond by RF on the control channel frequency identified by the channel number to send messages to the control channel and through that the nunked controller 79.

It a terminal 400 is unable to respond via the channel then it can instead spond by an IP path facilitated through the pairing with an associated smart device 401, Key to this response however is the identification of the control channel base station 201 so that messages can be route{ correctly. Preferentially, the unique ID of the control channel base station is used to create a message header 414 that the application 404 on smart device 401 can use to identify the correct control channel. This header facilitates routing of messaaes to the correct control channel base station. When the header is sent over the IP path then the IP address of the sender is also known, In this case it represents the IP address of the smart device. This header represents information needed to route between a terminal 400 and the control channel base station 201, including WACNID, System I D, RF Sub System ID, Site ID, Charnel, The header is stored within the application 404 operating on smart device 401. In another form, the header information could be stored within the multi bearer router and simply referenced via the IP address of smart device 401.

The base station 201 not only sends RF?SS and NET messages via RE but simultaneously sends these network to all other nodes on that network. This is facilitated by the voter sptittc.r 101 which automatically repeats signals on both Rh and IP cotrnmg Elegy'' to 711 controller 79, These messages are sent by the base station over the IP network which means a receiving node acquires both the messages and the IP address of the base station 201.Thc-multi bea er router has the IP address of the smart device 401 associated with the terminal, the IP address and unique P25 ID of the control channel base station 201. Given this information the NIFIR can route messages via IP between the control h -lel base station 201 and the terminal 400, A Receiver Report message is preferentially broadcast he IP network only, in this ease sent from the base station 201. This message identities the operating frequency of the base station 201 and the mode of the base station as either Control Channel or Traffic Channel, and. is periodically sent by all base stations on the network. These messages are received by the MBR which is aware of the mode and frequency of each base station on vstem. Focusing in particular on the triode, it the MBR knows which of the base stations represent control channels. Given this knowledge, the MBR can listen= and process only those messages emanating front the control channels or traffic channels that have been allocated for use at that time. This means the process requirement of the MBR can be scaled according to the current level of activity on the network.

Figure 6 is a sequence diagram for the broadcast of system information. The base station 201 periodically broadcasts over the IP network, the Receiver Report containing the frequency and mode of the base station. The Receiver Report is received by the MBR and, used to start building a table of relevant information for message routing. The NET STS BCST is sent fiom the trunked controller 79 to the base station 201. The base station. 201 repeats this via RF and IP. It is received by the terminal via RF and received by the MBR via IP. Again the infornaation is used to build up a table to facilitate message routing.

Finally, the RFSS STS BCST is sent by trunked centroller79 to the base station 201 which repeats this over RF and IP. The terminal 400 receives the message by RF and the MBR receives it via IP and uses the information to start establishing a table for routing messages.

Figure 7 indicates a, process for terminal registration, process that CUTS F as a reference for further explanation, The terminal 400 sends a unit registration, request 421 on the carrier frequency of the:control. channel base station 201. It is mewed and passed onto thu:Ittitiked controller 79, If the terminal is permitted on the system 'then the trunked controller sends back a unit registration response to the base station *high sends it over RF to the terminal In resppAse, if accepted, 440ct3, controller 79 sends the unit registration response back to the base station 201 which repeats it ey.cr RF and is received by the terminal 400: Figure 8 indicates a process by which the terminal 400 can undertake registration via the IP path. In this case the terminal has already detected the broadcast infomiation needed to uniquely identify-the control channel base station which it should communicate with The terminal 400 sends the unit registration request to the applicafion 404 which is resident on the associated smart device 401. The application 404 has already assembled a header as detailed earlier. The application 404 sends a message to the MBR containing its IP address and the header 414 and the unit registration request 421. Upon arrival at the MBR the message is routed to the bast; station 201 with voter 101. This routing is facilitated by a routing table in the MBR which knows the terminal ID, the IP address of the associated smart device, the IP address of the control channel base station and its P25 unique ID. Upon pith al at Eh, voter 101, it is passed onto the trunked controller. The terminal 400 may transmit RF also carrying the unit registration request. 'The voter would select one copy of the message or the other and pass it to the P25 trunked controller. In this case we have assumed the P25 terminal has either not transmitted over RE to save resources or the device is out of range. Upon reception of the message, the Quaked contmiler responds with a unit registration response which is muted back to the terminal via the MBR. The base station may transmit the same message by RIR.

Figure 9 indicates an example of registration when a multi bearer terminal has not seen any broadcast information via RF. In this case, the terminal does not know the address or frequency of a control, channel base station with which to communicate. The application 404 operating, on smart device 401 will have no header prepared. In the event of the terminal, seeing no broadcast information, it can still send a Unit Registration Request to the application 404 even though the WACNID and system ID may be unknown. In this ease, the applicadon will not add a header but just send the unit registration request 421 directly to the MBR. If the MBR receives a unit registration request without a header then it sends it to a default control channel base station. In this ease we assume the default is 201 in which case the message is sent onto P25 trunked controller 79. The controller responds with a unit registration response which is routed hack to the terminal. The terminal is now registered via the default control channel base station even though it can see no RF channels. In an alternative foam rather than routing to a default control channel base station, the MBR may route to the last known control channel base station via which the terminal was register. Alternatively,it could use location intbrmation to identify the closest physical control channel base le terminal currentlocation u 0 shows the normal method of grouts affiliation. The to spinal' 400 will end a up affiliation request on the control channel uplink to the base station 201. The base on noes the trunked controller. The winked controller 79 will then 2"o-up affiliation response to the base station 201 that transmits this over the P25 RF interface on control channel CC1. It is received at the terminal 400 and assuming the request was accepted, the terminal is now affiliated with that group.

shows terminal establishgroup a filiation via the IP path. A prerequisiteattempting group affiliation is the terminal must be registered. IY the terminal is egistered then, the application 404 must have established the infOrmi needed to create a header. Upon the terminal 400 sending a group affiliation request to the application 404, the application packages a header and a group affiliation request in an IP packet and sends this to the MBR 410. The MBR now sends this message onto the anon 201 which sends it onto the franked P25 controller 79. The controlle responds with a group affiliation response which is sent to the 'base station 201. The base station retransmits this via IP and optionally via RF, Via the IP path it arrives at the MBR. The MBR knows which terminal sent the request and which group it was seeking to join, so is able to send the group affiliation response back to the correct application 404 which then passes it to the tetminal 400 If the group affiliation request is accepted then the terminal is now affiliated to that group and will receive messages destined for that group. The MBR adds the group affiliation to its table so that further messages destined for this group are correctly sent to members of the group.

Figure 12 shows a process fiat group affiliation in the absence of any RF. if the terminal has only registered via IP'then it will have the default control channel base station m. It will use that to create the, message header. This header along with the group affiliation request is sent to the MBR 410. Given the known association between the control channel base station ID and its IP adds age is sent onto the base station 201. Base station 201 sends this onto the trunked controller 79 which responds with a group affiliation response. The group gro= I3 aff Nation response is sent base station 2ti1 to the MBR 410. The MBR extracts the group information an terminal D to add to the routing table before sending the message onto the smart device 401 inning app 404, It is then the terminal 400.

Figure 13 shows the process by which a rraz:lti'bearer terminal ablish a voice call normally. To undertake this, the terminal must already be registered and must already have affiliated with whichever groups an of interest. The terminal sends a Channel request on the control channel uplink to the base station 201, The'base station passes this message onto the trunked controller 79. The trunked controller responds with a Channel Grant that can be interpreted using the information contained within an Identity Update which is periodically broadcast by utrol channel. Specifically the information within the Identity update is needed to calculate the operating frequency of the assigned traffic channel, The assigned traffic channel is given in the channel grant, These are, sent to the base station 201 and then repeated over RE for the terminal to receive. If the request fora voice channel is granted then the terminal will be assigned to a traffic channel, in this case the options are TCH 1 or TcH 2 operating on base stations 202 or 203 respectively.

The channel grantand identify update uniquely identify the frequency to which the terminal should go for communicating its voice traffic. The key equation a terminal would use to identify the traffic channel is it sent to is defined in the TIA specification 02.AABC-C Trunked control channel message section 2,3.9,2. This equation is 30 given by Rx = (Base Frequency)±(Channel Numbe0x(Charmel Spacing), where Rx is the receiver frequency for that traffic ehamnel. The information needed for the terminal to Es calculate this frequency is contained within the channel grant and acid identify update e shall see in subsequent figures, the TMBR can use this equation to identify the unique ID of the control el:alai-lei and from that its IP address as opposed to irequtsm.y.

Figure 14 shows process for stabl!shi a voicein this ease, terminal 400 sends a channel request (Group Voice service request) to the application 404 operating on the smart device connected to the terminal 400. The application adds a header which identifies the control channel base station to which the request is destined for. The combined message is are packaged in an IP packet and transmitted to the MBR. 410. The TMBR extracts the unique ID of the control channel base station and looks up the IP address of that base station, in this ease 201. The message is sent onto 201 which the trunked controller 79. The trunked controller responds with a channel grant (Group voice service grant) and identify update which is sent to the base station 201. The be station 201 sends this message over the IP path to the MBR, The base station optionally sends the message:over:the'REi interfa message the MBR, 410 looks at the table to match the Upon recep Of the terminal against, the know IP address of the associated smart device and sends the message to the smart device 401 to be read by, the application 404, The application 404 unpacks the message and sends the channel grant and the identify update onto the terminal via a suitable digital.

interface.

e 15 indicates an example of voice call setup where there is no 11F connection at all. The device must already be registered which means the control channel base station II) will he known enabling the creation of a message header. This header is packaged with the voice channel request and sent in an IP packet to the MBR 410which reads the message and uses the header to route the message to the control channel base station 201. The control channel base station 201 sends that onto the P2,5 trunked controller 79. The trunked controller responds with a channel grant and identity update. This is sent from the base station 201 to the Malt 410 which extracts the channel information, base frequency and channel spacing. This is used to calculate the operating frequency of the traffic channel to which the call can been assigned. The T 4,fTfR also extracts group ID a his is needed to establish which terminals should have the call routed Figure 16 illustrator, the operation of a voiceon the uplink. Transmission via the RE path is normal operation. In this case the teindualhas been allocated to TCH2 which is associated with base station 203. Recall however that all base stations arc transmitting a Receiver report which includes the IP address'rf the sender, the mode of the sender and the operatmu frequency of the sender. This message is received by the MBR and used to update its routing table.

Furth when a Group wv ice service grant and identify update are sent to a erminal, they' contain the channel number to which they are assiimed. these messages et main the required information to establish the operating frequency of the traffic channel.

Specifically they contain, Base Frequency, Channel Number and Channel Given these values and the equation as defined TIC l02.AABC-C section23.92, the operatina frequency can be calculated as follows; Frequency (Bas Frequency) E ((Channel Number)x(Channepacing))., Given the frequency of the traffic channel from the RFSS and NET messages and also knowing the operating frequency and mode of each base station from the Receiver reports the MBR can identify the IP address of the base station to which the call has been uned. Further, the MBR knows the group affiliation of each terminal, Given the IF address of the base station 203 being used for the voice traffic is now known as is the group affiliation, the MBR can now route call information from the terminal 400 to the base station 203.

Has 203 now receives yoke rackets from the ter inal 400 via both RF and IP path; the voter contained within the base station 203 selects the best packets from either path and sends them on to the destination. If some terminals only connected via IP the destination may include the ME which will distribute information on ti smirk to all members of the group_ a voice the dowrdink path. The base station 203 is receiving voice from another source which we shall assume is affiliated to the same group as terminal 400. The base station 203 transmits the information over the RP path as normal winch means group members on the RF channel will receive it as normal. Simultaneously base station 203 sends the same information over the IP path which is received by the MBR 410. The MBR is aware of all group members and IP addresses of tem Mats associated with this oup un thischannel. It routes the voice message to all smart ()elated with the group. The application 404 on each smart device passes the mice to associated P25 terminal'.

Figure 18 shows a detailed flow diagram for the applica on 404 that oper o smart device associated with a P25 terminal. Following the start tn. the application ek ect 300 to the terminal device, connection can occur via a number methods as is well known in the art but here we assume Bluetooth. if the connection is not successful the attempt will repeat until it Once connection is complete, two th ones could occur dependingupon whether or not the associated terminal 400 is already rBred with the P25 netork. The application will establish control channel 11) information from the attached teaming using from P25 broadcast rnIbrntation, 301. If the radio has no control channel base station. ID flirtation then the application will wait a period of time before making the same 25 request.

11 the terminal does respond with control h nnel base station ID info nation 1.1 application will build a header packet which contains the unique P25 identity of the control channel base station 201. From here on, any message the terminal sends to the application willhave the header attached and then sent to the N1BR. Equally, any messages received by the MBR will be passed directly to the terminal and processed.

ternatiy elgt, if the terminal has not detected any broadcast information which idea the base schannel then it may send a registration request, 302. This registration request is sent directly to the MBR which responds with the ID for a default control channel base station or a preferred control channel base station. (liven the response information including broadcast data, the application now has sufficient information to create a header and proceed as norinal in future.

Figures I9A&B atc a detailed flow diagram of the MBR for a trunked LMR system. Initially the MER is waiting for a message to arrive. It processes various messages differently with a view to building up the requirol routing table to enable correct connectivity' of devices. If the MBR receives 290 a registration request then it will first establish if the request is preceded by a header identifying the control channel base station ID which the is seeking to comnitini,an. with If the header is not present the x the message is routed to a default control, channel base station and the default control channel base station ID is sent back to the terminal, f the registration request,ispreceded by a header ideritifyine k': c control channel base station ID then the unique ID of that base station is stored in the lookup table. Next, table is checked to see if an IP address matching that control channel base station ID is known. If it is then the registration request is sent to that control channel base station using its known IP address. If is it not known then the MBR simply waits for di message to arrive. It may optionally respond to indicate the control channel base st ID is unknown.

If the MBR receives 291 a Receiver Report from another base station on the system then the table is updated to record the IP address of that base station, its operating frequency and the mode of the base station either control channel or traffic channel. The mode can be used to shorten the search algorithm required when seeking to match a control channel base station ID versus its IF address.

iftlte MBR receives 297. either NET or RFSS System broadcast messages from a control channel base station the IP address of the sending base station along with the unique P25 ID of that base station is exacted and used to update the table.

up Affiliation itequest is received I then the IP address and source ID of the terminal are read. The unique P25 ID of the control channel base station is read from the header, if a known IP address existing table matching that P25ID then the message is muted to that control channel base up affili on eS p0 11 _oxatro channel base station then the target D of the terminal is read. The routing table is used to verify the LP address of the terminal. The Group ID is also added to the table and this terminal DIP address e is associated with the group. Having extracted the relevant routing information the group affiliation response is sent on ono the terminal/application.

If a voi.equest is received'295 from the terminal then-the control channel base station ID is read from the header. This is checked aga rst the routing table to establish the IP address of the control channel base station, The IP address of the smart device associated with the terminal is extracted along with the source ID of the terminal and this is added to the routing table.

If a voice char el grant tamed 296 fro a control la base then the 1P address of the 1 channel base station, he terminal ID, the channel, to which the grant has been assigned and the voup ID are extracted. The channel grant, is then routed to the fP address or the smart device associated with the terminal ID and to all the terminals that are members o s group. This is achieved by extracting from the routing table, the terminal ID's affiliated with the Group ID and IP addresses associated with each of those terminal IDs.

Next, acheek is made stablish tf the traffic channel number is known in the routing table. address that traffic channel is extracted using for routing. Voice messages arriving from an IP connected terminal such as 401 routed to the voter the traffic channel base station. In this case that's voter 103 in base station 203. Vbice messages arriving from the IP address of the traffic channel base station re routed to all IP connected terminals in this group with the exception at the sender. The channel bee is used to establish the IP addre SS of the traffic channel to which this voice call has been assigned. The routing of the call continues until the call is complete.

Figure 20 illustrates an example of routing table for clarit 11. D 123 is paired with a smart device w address xxx.I6.254.1. This multi.beater system is curren hannel 9 using group ID 17 and i °red with control channel base station ID A4397/2CC/8A/2/(1/2500).

Channel 9 is the channel number of the traffic.channelbase station with IP address xxx.16.254.21 operating on 171MHz which is currently serving Group ID 17. Is also has a unique identifier A4397/2CC/813/21(1/2509).

When communicating with a control channel the terminal ID will communicate with the control channel base station with I.nique ID A4397/2CC/8Al2/(1 /2500) that has IP address 5410. Iris operating 170Milz and is identified as channel 1.

reference to Figure from e P25 site 74 to the LTE site 7 e multi-bearer unit 70 begins transmittin P25 informaticin over both bearers simultaneously. In this case the implementation of the multi-bearer unit exists on a smart device connected to a to minal. These streams of inhumation 73 and 80 converge at a voter according the assignment of the plinked controller 103 which selects on a packet by packet basis the best in, m to pass onto the core network or M genend terms: the destination.

Within the multi-bearer device 3 call can be established as normal over the RE interface. At the same time, the processing I a : salt establish an 1P connection to the voter 103 located inside base station 203 its IP connection is established over any IP capable bearer with suf -: ient bandwidth to carry the information,. in this case ()meet over an IJTF or 46 cellula work via a c tosser through an IP network tot the voter 103.

21 details a flow diagram for the transmission of voice. Once a voice call is ed, the applicant) 404 will send the voice packets to the MBR. that will then be routed 315 to the correct base station. Voice information is then continually sent until the call is cleared down. The terminal may also send the voice via RP:which tinues in parallel 316 until such time the call is cleared down. Here wee assume that a calf is to be initiated across both bearers simultaneously. Initially the system is sea until a call starts.

Figure 22 illustrates the operatic; at the voter 103 contained within base station 203. The voter is seeing P25 packets arrive from both the RF path via a decoding base station and via ast IP path over a cellular wireless bearer. Consider this on a packet by packet basis.

T5 initiall} the voter is simply waiting for a packet to arrive, until an Audio Packet A arrives 321 he buffer. The system will record the error count for Packet A. It will need this later for the purpose of deciding which is the best packet. If the system is not configured for voting then implicitly it means there is only one path and so Packet A will passed to the destination. If the system is configured for voting then it means another packet is expected. As a result the system waits a predetermined time T for a packet B to arrive 322. If packet B fails to arrive then packet A will simply be sent to the destination. assuming a packet B does arrive then the system records the error count for that packet, An assessment is now made of packet A versus packet B. If packet B error count is larger than or equal to the packet A then packet A is sent 323 to the destination and the process for the current packet stops. If however packet B error count is less than packet A error count then Packet B is sent 324 to the destination. In an alternative ore can configure the voter to prefer a particular path if present and if above a certain level of quality defined by the error count or signed conditions or criteria more generally error count, Figure 2.3 illustrates an example where a handover condition may be occurring. in this case, we ssume a case where we are already working on a P25 RE channel. Periodically, both the P25 LivIR signal condition and the cellular signal condition are monitored by the application 404. In this case, we detect a situation where the LMR signal is becoming eak. The P25 transmission over RE continues but at the same time we initiate a cellular establish a suitable cellular bearer to support an IP pipe. Given the establishment of this IP pipe, the P25 data stream begins streaming from the digital interface of the radio to be transported to a base station, 203 (via the TIMBR, 410) capable of decoding the format of this information. Both the data stream from the P25 RF and the duplicate data stream via'the IP path are passed to the voter which selects best packets each time duplicates arrive. Those packets not considered best are simply discarded. The best, packets from the two streams are then sent onto the destination.

inure 24 illustrates a more detailed analysis of a handover process. A call has, been initiated with the P25 information available for transmission at both the RE port and the dal port on the radio. If the call is ended at any time then the P25 RE transmission and the cellular connection are both shut down. In other words the call is simply ended. If the call is not ended, then the condition of the LMR signal and signal is monitored 380. This typically means measurin mean measuring the current bit error rate or block error rate condition of the cellular al strength but can also other call control Given the above measurements a number of isions may be made, the [MR signal strength is above a threshold 1, then it means the current LIVER communication is very strong and could simply continue. A typical value. threshold 1 might be -90dBm. A cheek is made 381 to sec if P25 through IP is the preferred method of sending LMR. It is not then:he P25 over RE call simply continues, If P25 through IP is preferred then a check is made to see if the Cellular signal needed to support P25 through IP is above a threshold 3. If it is., it means the cellular call is strong hence P25 over RI can be shut down. If the cellular signal is less than threshold 3 then we continue the P25 call over RE.

If the LMR signal strength is less than threshold I however, then it may indicate edge of cell. Given this, and assuming cellular is available, a cellular connection must he established 382 in parallel, As a result, an IP pipe is opened to the target base station. Given this pipe, the P25 data is streamed to the remote base station. The result of this at is that two duplicate versions of the P25 stream arc now arming at the voter.

If the LMR. signal strength drops below another threshold 2 then there is no point in continuing the RE transmission because we are out of range. A typical threshold may be -120dBm. if the LMR signal remains above threshold 2 but below threshold I then the LMR transmission can continue. The terminal is hovering around the edge of range of the LMR system.

In the case of a cellular connection having been established, the signal condition must also be monitored. If the cellular signal is below a threshold 3 then a normal P25 call via RE is initiated. If the P25 RE call is already operating then there is no need to start a new one. A typical value for threshold 3 might be -8OdBm. If the cellular signal is above threshold 3 that we firstly cheek 384 to see if P25 via RF is preferred. If it is not then we continue with the cellular call. If P25 via RE. is preferred then a check is made to see if the LMR RE signal is above a threshold 1. If it is not we continue with the P25 over IP call supported by cellular. If it is above threshold 1 then we shut down the P25 over IF call and shut down the cellular connection supporting it.

In parallel, if the cellular signal has dropped below a threshold 4 which might typically be -100dBm. if the signal is above threshold 4 then the cellular connection is maintained. If the signal drops below threshold 4 then the cellular call is terminated 385 because the terminal is out of range.

Figure 25 illustrates an example where the communication is in the downlink as opposed to the uplink. In this case the source of information may be any device capable of producing P25. In this case the source is a P25 core network. The P25 information arrives at a voter 103 which also contains a splitter. This unit opens a standard P25 RE comimmication via a P25 control channel base station and simultaneously begins streaming the same P25 information in an IP pipe over an established cellular connection. The parallel streams of information arrive at the multi-hearer device where they are received over both cellular and P25 RF. A voting algorithm shown in Figure 7 is applied. The destination in this case is an application.

Figure 26 shows a flow diagram for the splitter 103 during downlink. If the splitter device is configured for multi-bearer operation then parallel communication paths 421, 422 are established over cellular and P25. The information is then transmitted simultaneously over both paths.

At the terminal side, there are a number of ways of receiving downlink information. In one fonn thi., terminal can imple,nent the same plocess as the uplink voter. Tn this from the terminal would make packet by packet decisions on information flow, An alternative form is shown in Figure 27. Typically, LMR terminals are capable of scanning or voting.

In the case of seaming, the terminal will measure signal strength or some other quality factor on each RF channel and lock onto the first one it sees, In a voting form the terminal measures signal strength of each channel and selects the best channel. Other forms are possible.

In this case, one of the channels is now an IP path via a cellular device. Techniques of scanning and voting can be applied across the LMR channels and cellular channels. Figure 27 details an example. Here, upon the start of a downlink communication, the algorithm measures 425 the signal strength of the RF path and records it as A. It then measures 426 the signal strength of the cellular path, B. The best path is then selected whereupon the remainder of the voice over is received by that one path. In an alternative form, we could use a rule that always prefers the use of cellular if packets are present.

In the example of Figure 27, one RF channel and one cellular channel is measured.

Clearly, multiple RF channels can be assessed and multiple IP paths. Further, acceptable cellular signal strengths may be different to LMR. Such differences are taken into oust with scaling. Further; any form of signal quality measure can be used. rig not limited to bit error rate, message error rate and audio quality.

Referring back to Figure I illustrates the main components of a system to enable seamless migration between P25 and IP over LTE. The multi-bearer device 70 is moving out of the LMR coverage area into the coverage of a cellular LTE base station 71, Whilst moving from the P25 coverage area to the LIE coverage area the multi-bearer unit 70 begins transmitting P25 information over both bearers simultaneously. These streams of information 73 and 80 converge at a voter, 101 which selects on a packet by packet basis the best information to pass on to the core network or in general terms the, destination. It should be noted the multi-beat highlights the key components of a multi-bearer device, such as shown in Figure 4.

Conventional LltlR systems do not resluire control channels but otherwise have many es to tr riled systems as described above. The functions of the multi bearer terminal and multi bearer router in an integrated IP and conventional LMR system are therefore similar but less complex.

Figure 29 schematically shows a multi bearer outer MBR 810 in a conventional' system. The MBR has the IP address of a smart device 801 and the radio ID of the associated P25 terminal 800. Further. the MBR has the IP address of the traffic channel base station 601. Given this information it can route messages via IP between a traffic channel base station 601 and the terminal 800. In this example the MBR also knows the Talk Group ID of which radio 800 is a part. The MBR builds up this information into tables that can be used to route traffic. Alternatively the MBR may be configured manually.

Figure 29 also identities the Receiver Report message 4 that is preferentially broadcast over the IP network by all base stations m the system. In this case it is sent from the base station 601. This message identifies the operating frequency of the base station 601 and the triode of the base station. In a conventional radio ease tins is a Traffic Channel. This message is periodically sent by all base stations on the network and can he received by any other network component including the MBR.

Figure 29 shows a process of registration for a terminal in an integrated conventional LMR and IP ne,twork. It is necessary the multi-bearer system made up of devices 800 al id. 801 and 804 register their presence with the MBR 810. Primarily this is to enable the MBR to establish the IP address and group membership relevant to that system so that information can be routed to/from it.

Upon switch on or upon connection, the system made up of radio 800, smart device 801 and application 804 running on smart device 801 must register with the MBR 810. To accomplish this the application 804 creates a registration message 414 containing, the radio ID, the Talk group Ills of which this radio is a part, and the II' address of the smart device. The purpose of this message is to register the smart device IP address with the MBR" rather than for Land Mobile Radio registration. The IP address of the MBR can he known prior by the application 804. Upon arrival of the header 414 at the MBR the information is extracted and used to build a routing table associating Talk Group!Ds with Radio His and the IP addresses of those Radio IDs. Also associated with the Talk Group ID are the IP addresses of the base stations sending information about those groups.

Figure 30 shows an automatic method for building up the routing table in the MBR, 810. In P25 operation, the voice header 417 contains the Talk Group ID of the target radios for which the communication is destined. The base station is sending the voice streams via both the RF path and over IP which means it is received by the. MBR 810. Having received the voice header 417, the MBR now knows there must exist a Talk Group ID of that described in the header 417. As a result, the MBR can start building a table entry for that Talk Group ID whether or not a Radio II) has registered with the MBR via IP yet.

Figure 31 illustrates a sequence diagram for the downlink voice stream in a conventional 30 LMR and IP system, focussing solely on the stream via the FP path. Voice header 417 and voice packets 418 are sent to the MBR 810. The NI13R uses its routing table to pass the voice stream onto the application 804 operating on smart device 801. The application then passes the across to the radio 800 which can operate according to its usu behaviour e.g to 2 indicates an uplink voice stream. The radio 810 transmits a voice header 417 and voice packets 418 via both RF and IP. It sends the stream across to the smart device 8171 where upon the application 804 re-transmits the messages 417, 418 to the MDR 810. The MBR uses its routing table to send the stream to the relevant base station or base stations 601.

Figure 33 illustrates a table of example device identities. In 1 MBR is located at IF address xxx.20.254.100. This represents a default address to which the smart devices of the multi-bearer system can communicate. One such multi-hearer system is represented by the radiol, smart device 1 pairing identified as Radio ID 123, IP address xxx.20254.1. Further examples include radio 2, 3 and 4 associated with smart devices 2,3 and 4 respectively. Radio ID 123 is a member of group 18.

e such example is located at IP raffic and associated with Talk The tabu: of Figure 33 ate shows t ree bas address xxx 6.254.21 acid is operating on 1711 20 Group 17.

34 illustrates a routing table with two groups 7 and Each row in the table identities' the base station IP addresses associated with each Talk Group ID and mart device IP addresses associated with each Talk Group ID.

Talk Group ID I e base station operating on IP address xxx.16.2;54.23, This base station i operating on frequency 171Mblz, Further, the IP addresses of the smart devices associated with this group include xxx.20.254.3 which is connected to Radio ID 125 and xxx.20.254,4 associated with Radio ID 126.

Talk Group ID 18 is associated with a two base stations 'crating on IF addresses 6.254.21 and xxx.16.254.22. These base stations operate on frequencies and I72MHz respectively. In is a normal mode of operation in Land Mobile Ra term n across multiple frecuencies and selecting the channel frequency v hic range. The IP addresses of the smart devices associated with this group include xxx20.254.1 which is connected to Radio ID 123 and xxx,20.254.2 associated, with Radio ID 124.

Figures -A&B area flow diagram illustrating processes in the MBR for a conventional LIVIR network integrated with an IP network. By default, the MBR is waiting, for a message to arrive, If a registration request arrived 690 from a smart device connected to a radio then the MBR extracts the IP address of that device along with the Radio ID and nip Ms, This infomuition is stored in the table.

receiver report arrives 691 front: a base station then e extrac ddress, frequency information and mode of the base. It should be noted that ii radio context, the mode will only be traffic as opposed to control.

If any other message arrives 69 from any other smart device then a check is made to establish if that device is registered. Wit is registered then its Group ID is used to route its messages to all base stations or smart devices associated with that group. As a result all members of the group whether they are connected via IP or through RF connce base station will receive the transmission.

other message arrives 69 om a base station, then the group ID of the message is read and used to enable routing of that message to al of ces ated with that group, As a result all members of the group whether they are connected via IP or through RI; connection via a base station will receive the transmission.

e 36 details a flow diagram fin the transmission in a conventional similar to calls, in a trunked system. Willy the systeits is waiting until a call Once a voice call iated, the application 404 will send the voice packets to the MBR that will then be routed 815 to the correct base station, Voice information is; then continually sent until the call is cleared down. In Figure 69, the terminal sends the voice information via RE. That continues in parallel 816 until such time the call is cleared case a call to be initiated across both bearers simultaneously. Initially the 1, until The stream of P25 code words is continuously streamed out of the radios, processed according to a format required by the destination then transmitted across the IP path to 10 the remote voter. Simultaneously a normal P25 call is establishedover the RF interface and the same P25 eodewords are'transmitt d over RE This parallel 'ssion over both P25 RP and P25 in IP continues until trse call is cleared down as t The method by which the voter was described earlier with refere ci a conventional LIvIR network, es and uses the data streams a franked coat i tare 22 to 24. This part of process is the c 37 illustrates an xaaaaple where the communication is in the downlink as opposed to the uplink. In this east, the source of information may he any device capable of producing P25. In this case the source is a P25 core network. The P25 information arrives at an information splitter which is part of a voter. This unit opens a standard P25 RF communication via a P25 site and simultaneously begins streaming the same P25 information in an IP pipe over an established cellular connection, The parallel streams of information arrive at the multi-bearer device where they are received over cellul P25 RP together. The destination in this case is an application. A voting algorithm such as that shown in Figure 7 can be applied, Alternatively the terminal can use very simple rules for example; if RE signal is present then receive the rest of the over using that path. Alternatively, if P25 in IP is present then receive the rest of the over via that path.

Figure 38 shows flow diagram for downlink. If the splitting device is configured liar multi-bearer operation then parallel communication paths can be established over cellular and P25. The information is then transmitted simultaneously over both paths 730, 7 At terminal side, there area of.ceiving downlink information. in one form the terminal can implement the same process as the uplink voter as described in Figure 36, In this form the terminal would snake packet by packet decisions on information flow. An alternative form is shown in Figure 15 involving scanning. Typically, LIVER, terminals are capable of scanning or voting. In the case of scanning, the inal Imply measure signal strength on each RF channel and lock, onto the first voting form the terminal measures signal strength of each channel and selects hi this case, one of the channels is now an IF path via a cellular oevice. We can apply similar techniques of scanning and voting here across the L11 R channels and cellular channels. Figure 10 details an example. Upon the start of a downlink communication, the multi-hearer terminal measures the signal strength of the RF path and records it as A. It then measures the signal strength of the cellular path, B. The best path is then selected whereupon the remainder of the voice over is received by that one path.

the a p f Figure. one RF channel and one cellular channel are measured 740, 741.altiple RF channels can be assessed and also multiple 1P paths. Further, it is important to note that acceptable dlular signal strengths'may be different to LMR. Such differences are taken into account with scaling. Further, any form of signal quality measure can be used including but not limited to bit error rate, message error rate and audio quality. 31.

Claims (2)

1. CLAIMSI.. A method of operating a router aulti bearer radio system having an LMR wire!. s bearer and an IP wireless bearer, including: establishing device data in the router having an LMR Iii and an P address for each of a plurality of multi bearer devices in the system, and establishing site data in the router having an IP address a plural o LMR bearer base stations in the system and an IP address for each of to plurality of IP bearer base stations in the system.
2. 2. A method according to claim I wherein the site site,data includes frequency and mode for each or the LMR bearer base stations.A method according to claaim I further including: receiving a message firom an _R bearer base st R. con capsulated as IP data, and tiransmitting the message to an IP bearer base furthermission to more multi bearer devices.A method according to claim ther including: receiving a message from an IP bearer base station in Corm of content aalasulated as IP data, and transmitting the message to an I,MR bears base station, for RE trans issio a to bearer devices.hod according to laim I wherein the site data includes an IP address for base stations which provide an LIVIR control channel.one or 6. A method according to la for one or more of the multi hearer devices.n the device data includes a talk group ID 7. A method according to claim 5 further including: receiving an LMR registration request from a multi bearer device via n IP bearer base station, and transmitting the LMR registration request to an Lts4R base station which pro a control channel for the device.A method ccording to claim 7 further including: receiving an LMR registration response from said I,MR base' station v h provides a control channel, and transmitting the LMR registration response to id mu bearer device via an IP bearer base station, A. method according to claim 8 further including: Mg a group registration:request from a n?ulh bearer d vi base station, and transmitting the group registration message to an base station which provides a control channel for the device.10. A methr d according to claim 9 further including: a group registration response from aid C,Arld base st which provides a control channel, transmitting the LMR r stranon response to.said rtrulti bearer device via an IP bearer base station, and establishing a group registration ID for said nu hearer devw A method of group eom^tuniaatior betty n multi bearer deviies in a conventional LMR system, including: receiving LIVIR, ID. group ID and IP address it tomtation from the multi bearer devices storing the LMR ID. ow II) and IP address infot nationfrom the devices, in a router.receiving group ID and IP address information from traffic hamlet base stations in the -sto group ID and IP address information from the base stations, it the router; and routing group communications between multi bearer devices in a common groat) according to the II' addresses of base stations which serve the multi bearer devices in the group.12. A method according to claisx 11 wherein the router identifies the IP addresses of the base stations through if broadcast reports containing frequency of operation and mode.13. A method of registration in a trunked LMR system including, initiating an LMR communication using a ii-bearer device capable of both LMR, and IP communication, receiving broadcast information detailing the ation of the I,MR system includingthe identity of a. control channel base station.using said broadcast information to t,stabhsh a header packet to enable c.oantnctnic^ation to the control channel base station, device over an IP path to:a router, transmitting said header and LMR registration content: transmitting identifying inform station the system to the from router.receiving said header and I.MR rus istrationthe itmin-bearer elexrize at the rout using the,, identifying information from each base station and routing I Iv1R. registration to the base station serving the multi bearer device, transmitting said LMR registration from the receiving base static a trankeci control receiving a,registrati n response from the trunked controller at the base on trallSillitting the regT siration response to the router, and receiving registration resg onse at the trunked r ansral is to the multi-bearer device.14. A method according to claim 13 wherein the header is established through IL,MR broadcast information including the RFSS System Broadcast and Network Broadcast.15. A method according co clams 13 wherein the routs identifies the IP address of the control channel base station by receiving broadcast information regarding frequency of operation and mode of the station encapsulated in an IP packet.16. A trunked radio o on systei for users having radio equipment which provides both LMR and IP capability, including: a first network of base stations which provide LMR services to he users, having a control channel base station and a trunking controller, and a second network of base stations which provide eellulai IP sers, :laving a router containing a table of LMR identities and corresponding IP addresses, wherein the control channel base station sends and receives control messages to and #cairn users of the system through the first network, and the control channel base station sends and receives control messagesto an use system through the second network, the router fOr mapping, between LMR and IP message protocols.17. A system according: to clai n 16 wherein the control messages include requests sponges relating to registration, group affiliation and call setup.1 8, A system according to claim 1 S wherein messaves from a user are sent to a base station serving the user in the first network, and also to a base station serving the user in the second network, and from said base station in the second network via the router to said base station in the first network, for a voting process.19. A system according to 18 wherein messages to a user are sent via a ha n serving the user in the first network, and also vvia the router to a base static senriing the user in the second network, -a handover pro° 2ti. A conventional radio communication system fot users having radio equipment which provides both L.N4R and IP capability, including; a first network of traffic channel base stations which provideR sew Lasers, and a second network of base stations which provide cellular" IP services to the users, having, a router containing a table of MIR identities and corresponding IP address wherein the traffic channel base stations send and receive messages to and fr to system through the first network, and the traffic channel base stations send and receive messages to and from ca the system through the second network, tt ter for mapping between 1.:NIR land