|Latin America I 1999
|MAP27 Protocol:Developing New Applications for MPT1327 Trunking
|Mr. Pavel Repin
|Condor Communications, USA
Advances in technology have allowed trunking techniques, previously only associated with hard wire communications, to be applied to radio networks, which enables more efficient use of the radio spectrum. Condor has developed several MAP27 solutions and applications. By combining the list of features of MPT1327, trunking systems, price, performance, channel efficiency and ability to create new custom MAP27 applications, it opens many opportunities for wireless customers, operators and vendors alike.
Advances in technology have allowed trunking techniques, previously only associated with hard wire communications, to be applied to radio networks. These allow more efficient use of spectrum. Radio spectrum throughout the world is becoming congested. The dynamic growth in mobile communications has made channel availability very difficult and the increasing consumer demand for the benefits of mobile communications means that more and more users need to be given access to the same number of channels, without any loss of quality of service. Benefits of MPT1327 Trunking Protocol 1327 (MPT1327) is a family of standards which defines a trunking system for Private Mobile Radio (PMR). A conventional PMR service offers the user a single channel. When the user wishes to make a call, this channel may well be occupied by another user. The prospective user must wait until the end of the conversation and then compete with others to obtain the vacant channel. In a trunking system, a set of channels shares the communication demands of the users. If no channel is free at the time a user makes a call, the call will be placed on hold for a few seconds until any channel becomes available. As a result, the user has less time to wait and enjoys a better quality of service. What is MAP27? MAP27 is defined as Mobile Access Protocol for MPT1327 communications equipment. In brief, it permits data exchange between MPT radio trunking equipment and external equipment such as a data terminal which may be a laptop computer. The external equipment is able to command the radio to set up calls to a particular radio unit, send and receive status and data messages etc. MAP27 defines the hardware and software data interface protocol, developed to provide an open standard in order that application programs can be created for MPT1327 communications systems irrespective of specific manufacturers equipment. MAP27 is a standard that specifies a set of commands sent via serial interface between radio and device or computer. Any radio that understands MAP27 should be able to ‘talk’ to other MAP27-compliant devices. A Global Positioning Systems (GPS) receiver with a MAP27 Interface can serve as a typical example of such a device. A computer can easily be connected to the radio and software can be designed to perform various radio trunking activities- calling, messaging, dynamic regrouping and call diverting, just to name a few. MAP27 includes procedures for sending: · Status messages: The status message is a number between 0 and 31. · Short data messages: Up to 176 or 184 bits of free format data or 25 ASCII characters. · Extended data messages: Up to 704 bits of free format data or 100 ASCII characters. · Standard data messages on a dedicated data channel. Packet switched data with a defined bit rate of 1200 bit/s but an option for customised higher bit rates. The procedures and connections specified in this standard are sufficient for several types of data communication. Specific user needs to include: · Acknowledged messaging; · Letter type messaging/mailbox; · File transfer; · Interactive terminal; · Modem calls; and, · Automated speech-‘call control. Applications of MAP27 Various pieces of equipment can collaborate over a trunking radio wireless network, using different interfaces. One can distinguish three classes of equipment: · MAP27-compliant devices: This type of devices connects to a MAP27 radio directly without any intermediate interface, like GPS receivers and telemetry systems supporting MAP27. The data collected is transmitted over the air to be interpreted by software programs. · MAP27 Software: This type of software is a very important part of any wireless data processing system. Software runs on a computer that can connect with other computers on a Local Area Network (LAN) or the Internet. Users can interact with · remote equipment, monitor it and control it. The computer can also be used as a gateway – in this case it runs unattended tasks that relay data using standard networking protocols. · MAP27 Controller is a ‘black box’ that allows the use of equipment, which was not originally designed to be part of trunking radio networks. A Controller serves as middle-ware between a MAP27 radio and some arbitrary device. It should be programmed to handle the data from the device and translate it into short data messages or, maybe, longer data transfers over a dedicated data channel. As part of this process, there will be a computer running MAP27 software (or another specially programmed MAP27 controller and a device) which takes care of that data on the remote side of the radio link. Areas of Usage Emergency Dispatch Centre Emergency Dispatch Centres consist of one dispatch talk-group that allows communication with the idle units. Initially all radio units belong to this dispatch group. The mere functionality of this concept is best explained in the following example: Incident – football fan confrontation near the Stadium: the operator finds the officers who are near to the incident location and puts them in a new dynamic talk-group. From then on, these officers will be able to communicate with each other in this group during the operation. This form of communication offers a number of advantages. Instead of having to switch channels, they concentrate on their work and are not distracted by the idle radio traffic of the dispatch talk-group. As additional reinforcements arrive, they are regrouped to the same group or some additional groups as required depending on the situation. The senior officers can be assigned to several groups enabling them to monitor the various activities. As soon as the situation is under control, the talk-groups are disbanded (ungrouped) and everybody will ‘return’ to the dispatch group. A dispatcher computer using MAP27 Interface with a portable or mobile radio is capable of managing the regrouping. Also, the person in charge of regrouping can be on the location of the incident, supervising and organising additional reinforcements. Short Data Messaging Short Data Messaging enables the sending of small amounts of data with acknowledgement. MAP27 can therefore be a really useful communication tool in areas such as: SCADA/telemetry projects, alarm and monitoring systems, remote barcode inputs and GPS applications. Condor Communications’ MAP27 Involvement Condor has developed several MAP27 solutions and applications: · The software development kit: This is an advanced library of the most required MAP27 functions that allows us to develop custom solutions rapidly. This software is being used in-house for projects with MAP27. Besides, the kit includes an addressing tool that maps internal MPT1327 Idents (subscriber radio unit IDs) to user-friendly subscriber numbers which reflect the structure of subscriber’s organisation. · Radio dispatch system for National Police of Guatemala: It is a system that performs telephone call logging and dispatching of calls to local police departments. The database shared by a number of workstations, stores all transactions and event information. There are two types of dispatch operators: Telephone Operator and Dispatcher. A Dispatcher is in constant communication with their corresponding police department relaying messages. A Dispatcher’s workstation is connected to a radio via MAP27. A Telephone Operator is responsible for logging all the calls and allocating them to a proper Dispatcher depending on the location of the event. · CondorRDS 2.0, a general purpose MAP27 radio dispatch system: This is a software package which supports status and text messages, voice calls, calls to landlines (PABX/PSTN), dynamic regrouping, database tracking of all events and multi-user capability for a small dispatch centre (up to 5-8 computers). · CondorRDS 2.0 PLUS, a system for custom messaging applications: In essence it is very similar to CondorRDS 2.0. Yet it has got a crucial additional feature: a compact software developer kit for status and text messaging. Anybody with experience in programming with ActiveX tools such as Microsoft Office applications, can create their own MAP27 messaging applications. New Developments Condor is currently developing a hardware solution, which will not depend upon the use of a computer. The principle is a small ‘black box’ that has a MAP27 Interface, a couple of serial ports and other interfaces. It packs an advanced digital/analog codec, which opens up the possibility for data transfer over a dedicated data channel. It can be programmed to interact with various third-party appliances and devices like telemetry systems, alarm systems arid barcode readers. Due to the abundance of possible MAP27 applications it is hard to predict what the customer requirements of the future will be. Generally, Condor is working to increase connectivity options for its software – web gateway projects, which can possibly be used for extranet/intranet applications. Email client integration can also be useful for relaying short email messages to radio units. Conclusion By combining the list of features of MPT1327; trunking systems, price, performance, channel efficiency and ability to create new custom MAP27 applications, it opens many opportunities for wireless customers, operators and vendors alike.