Paging technical information
Paging networks in the UK use either POCSAG or FLEX protocols to transmit paging messages over the air to paging receivers. The POCSAG protocols can operate at three speeds, 512 bits per second, 1200 bits per second, or 2400 bits per second. Flex protocol speeds are higher and use four level modulation techniques. achieving 1600 bits per second, 3200 bits per second and 6400 bits per second.
Each radio channel uses a narrow band 25KHz channel spacing that can support up to 50,000 uses representing a highly efficient use of the radio spectrum.
Paging networks in the UK will operate around 500 transmitting base stations that provide resilient coverage overlap in high population areas and can provide the best out door coverage in very rural areas such as central Wales and the Highlands and Islands of Scotland where no other form of personal radio coverage is available.
Paging networks operate in a broadcast mode that sends a message to each of the transmitters simultaneously, but this does mean that the more traffic a paging network has to send the slower it becomes in sending that message until the network goes into congestion causing message delays. Well run paging networks have a number of safe guards against such problems by protecting the network at the input stage using sophisticated grade of service controls as well as more radio channels to spread the traffic load.
Some paging wide area networks are operated completely independently of the mobile networks and could therefore provide useful resilience if mobile networks should fail or go into congestion as experienced with the public incidents such as the New York and London terrorist attacks.
Paging is still today providing a vital resilience service to many corporate and blue light users who are seeking backup and multiple communications strategies as a result of these experiences.
