Classifications

• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04W—WIRELESS COMMUNICATION NETWORKS
  • H04W84/00—Network topologies
  • H04W84/02—Hierarchically pre-organised networks, e.g. paging networks, cellular networks, WLAN [Wireless Local Area Network] or WLL [Wireless Local Loop]
  • H04W84/022—One-way selective calling networks, e.g. wide area paging

Definitions

• This invention relates in general to radio paging systems and more particularly to a nation-wide paging system with multiple local modes.
• Paging systems typically use a receiver that has at least one unique selective call address associated therewith. This receiver is commonly referred to as a selective call receiver or pager.
• a pager receives and decodes its address, the pager typically alerts the user to the presence of incoming information and operates to present this information.
• the receiving, decoding, alerting, and presenting sequence as well as other functional aspects associated with the pager are commonly referred to as the pager's personality.
• a unique operational personality is programmed in the pager by the service provider before delivery, and generally cannot be modified by the user or provider without returning the pager to a service depot. Wide area paging systems for the transmission and reception of radio frequency information are well known to those skilled in the art.
• the user's pager will then be able to receive the correct radio frequency carrier and address information, but because of the sheer volume of information associated with a network of this kind, the message may take an hour before broadcast to the user. If the user happens to travel to a location where a different service provider has a paging system on the user's assigned radio frequency carrier, chances are that the user's pager will not function.
• Fig. 1 is a system infrastructure diagram in accordance with the preferred embodiment.
• Fig. 2 is a diagram of prior art wide area selective call signalling format.
• Fig. 3 is a diagram of the improved wide area selective call signalling format in accordance with the preferred embodiment.
• Fig. 4 is a block diagram of the selective call receiver system in accordance with the preferred embodiment.
• Fig. 5 is a flow diagram of the selective call receiver's personality selection algorithm in accordance with the preferred embodiment.
• the most important criteria is the raw throughput available as a function of the system loading (the number of users attempting to access the system at any point in time as compared to the number of messages pending transmission) , baud rate (the number of data units transmitted per second) , and the efficiency of the addressing scheme.
• a digital selective call addressing scheme such as POCSAG (developed by Great Britain's Post Office Code Advisory Group) or Golay Sequential Code
• the number of selective call addresses available in a digitally coded system is limited only by the effective length of the addressing word.
• pager selective call receiver
• the preferred embodiment of a wide area selective call signalling system comprises networked base stations that are accessed via data entry devices (eg. computers, telephones) .
• Each base has its own selective call signalling encoder and transmitter.
• the transmitters may have more than one frequency (denoted on Fig. 1 by Fl, F2, F3, F4) depending on the channel loading in a particular area.
• the New York area 101 uses three frequencies, Fl, F2, and F4.
• the user's pager When the user travels to New York 101 or Chicago 103, the user's pager will respond to the local area address assigned in the respective areas. This local area address is automatically selected by the user's selective call receiver when the New York 101 or Chicago 103 area location ID is recognized. In Chicago, 103, the pager scans receive frequencies until it receives and decodes the location ID transmitted on frequency F4 (for example) then automatically switches to the predetermined receive frequency Fl and loads the predetermined local area address for Chicago 103. When the pager no longer receives the transmitter signal, the user has left Chicago 103 and the receive frequency automatically reverts to its nation-wide frequency scanning mode.
• F4 for example
• the user would call the service provider and request that the Miami 102 system broadcast messages directed to the user on the pager's nation ⁇ wide address.
• the Miami 102 system would then broadcast messages directed to the user on the pager on all available frequencies using the nation-wide address of the pager.
• the pager may receive messages in Miami 102. While causing the system in Miami 102 to "bog down" by sending messages with longer nation-wide addressing on a plurality of frequencies. Note the same messages are transmitted in New York 101 and Chicago 103 on a single frequency with a shorter local address thereby relieving "bog down" in these areas.
• a selective call signalling format comprises an address field 201 and message field 202.
• the address field comprises pager addresses of one word 203 and two words 204.
• the single word pager address 203 and dual word pager address 204 have corresponding information in message A 205 and message B 206, respectively.
• the preferred embodiment of the improved wide area selective call signalling format comprises a location identifier 301, address field 302, and message field 303.
• the address field comprises pager addresses of one word 304 and two words 305.
• the single word pager address 304 and dual word pager address 305 have corresponding information in message A 306 and message B 307, respectively.
• Interleaving, as used in selective call signalling protocols, is defined as the orderly insertion of a predetermined information word (for example an address or pre- address data word) within in a data stream.
• a location identifier it is broadcast in a time window that has minimum and maximum spacings specified between transmissions in order for the pager to properly recognize the location identifier.
• the improved wide area selective call signalling format transmission is interleaved at a predetermined interval with the selective call signalling format shown in Fig. 2 to provide transmission of the location identifier 301 for reception by active paging receivers.
• the location identifier 301 may be transmitted in a stand-alone fashion (meaning there is no connection with the actual addressing-messaging data block shown in Fig. 2) while maintaining an acceptable interleave interval for detection by active paging receivers.
• the block diagram shows the preferred embodiment of a battery 401 powered selective call receiver (pager) which implements the present invention.
• the transmitted signal is coupled via an antenna 402 to the receiver 403 for recovery of the modulated data.
• the recovered data is coupled to the controller 404 and decoder 406.
• the controller 404 manages the operation of the pager's receiver 403, decoder 406, user controls 405, alert 408 presentation means, and display 409 presentation means.
• the controller 404 commands the decoder 406 to read the default wide area information from the code plug 407.
• the pager then configures its operational characteristics according to the data read from the code plug 407 associated with the wide area mode.
• the decoder notifies the controller to take the appropriate actions to alert the user and present the received information.
• the pager will configure its operational characteristics accordingly and search for the address associated with the active location ID.
• Each location ID as well as the wide area default structure has a personality associated with it. These "personalities" are programmed by the service provider and comprise a selective call address, receive frequency, protocol mode, presentation mode, and operation mode.
• the code plug 407 is shown having 4 personalities. Three of the personalities are dependant upon the pager being in one of three predetermined areas and the fourth personality being dependant on the pager being in an area other than the three predetermined areas. Using the location ID as the determiner, the pager can alter its complete mode of operation when travelling from one area to another.
• This feature can be very useful if, for example, a user desires a fully functional alphanumeric pager in the area where their home office and local paging service provider has alphanumeric input capability, and a low latency tone-only numeric pager in a rural area where the paging service provider may only have tone-only numeric capability.
• the first personality having alphanumeric capability uses a local address (an address option that lowers the service provider's system overhead), local area frequency F2 (a frequency dedicated for local area addressing) , high speed coding (a protocol mode option for faster information delivery) , extended frame data interleaving (a protocol mode option for improved battery life) , alphanumeric display (a presentation mode option allowing the display of both numeric and alpha characters) , and silent alert capability (an operation mode option enabling a mechanical vibrator when alerted) .
• the second personality having tone-only capability is set-up as the default wide area personality.
• the second personality uses a two word wide area address (an address option) , wide area frequency Fl (a shared frequency dedicated for wide area addressing and location identification) , normal speed coding (a protocol mode option) , normal frame data interleaving (a protocol mode option for normal battery life) , numeric display (a presentation mode option allowing the display of numeric characters) , and audible alert capability (an operation mode option enabling an acoustic transducer when alerted) .
• address option wide area frequency
• Fl a shared frequency dedicated for wide area addressing and location identification
• normal speed coding a protocol mode option
• normal frame data interleaving a protocol mode option for normal battery life
• numeric display a presentation mode option allowing the display of numeric characters
• audible alert capability an operation mode option enabling an acoustic transducer when alerted
• the protocol mode selected within a personality functions to control parameters associated with the selective call coding format such as the baud rate (number of information bits per second) and receiver battery saver rate (the on/off strobing of circuitry within the pager to extend battery life) .
• the presentation mode selected within a personality functions to control parameters associated with the pager's information presentation means. Examples of selections available for information presentation are numeric, alphanumeric, or graphic modes.
• the operation mode selected within a personality functions to control parameters associated with the pager's messaging capability and alerting functions.
• Messaging modes can include tone-only, tone numeric, tone & voice, tone & voice numeric, or alphanumeric to name a few.
• Alerting modes commonly used include audible tone alert and sensible vibrating alert as well as a selection between various alert tones, patterns, or melodies.
• the pager when the pager is activated 501 it loads the default personality that corresponds to the wide area paging mode 502. When the pager is in the wide area paging mode, it continuously searches each channel (frequency) for received data indicative of a protocol for which the pager receives messages. The data may be in the form of a baud rate or a predetermined synchronization signal. Upon finding such a channel, it searches for its corresponding wide area selective call address and any local area identifier that is broadcast. If a valid local area identifier is detected 503, the pager then selects the appropriate local parameters that correspond with the detected local area identifier.
• the selected local area personality is enabled by selecting the local paging address 504, local receive frequency 505, local protocol mode 506, local presentation mode 507, and local operation mode 508.
• the pager changes from the wide area mode to the local mode 509. If the signal transmitted from the paging base station is lost 510 for a predetermined period of time, the pager will revert to the wide area paging mode 502.

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• Engineering & Computer Science (AREA)
• Computer Networks & Wireless Communication (AREA)
• Signal Processing (AREA)
• Mobile Radio Communication Systems (AREA)
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Cited By (6)

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Citations (3)

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• 1990
  • 1990-09-20 AU AU65251/90A patent/AU6525190A/en not_active Abandoned
  • 1990-09-20 JP JP2514072A patent/JPH05501336A/ja active Pending
  • 1990-09-20 WO PCT/US1990/005513 patent/WO1991006190A1/en not_active Application Discontinuation
  • 1990-09-20 KR KR1019920700873A patent/KR920704533A/ko not_active Application Discontinuation
  • 1990-09-20 CA CA002065274A patent/CA2065274C/en not_active Expired - Fee Related
  • 1990-09-20 EP EP19900915018 patent/EP0497792A4/en not_active Withdrawn
  • 1990-10-08 MX MX022733A patent/MX171854B/es unknown

Patent Citations (3)

Non-Patent Citations (1)

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