WO1982004514A1 - Systeme ameliore de decodage de recherche de personnes - Google Patents
Systeme ameliore de decodage de recherche de personnes Download PDFInfo
- Publication number
- WO1982004514A1 WO1982004514A1 PCT/GB1982/000160 GB8200160W WO8204514A1 WO 1982004514 A1 WO1982004514 A1 WO 1982004514A1 GB 8200160 W GB8200160 W GB 8200160W WO 8204514 A1 WO8204514 A1 WO 8204514A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- synchronization
- synchronization codeword
- decoding
- codeword
- erroneous
- Prior art date
Links
- 230000005540 biological transmission Effects 0.000 claims abstract description 14
- 238000010586 diagram Methods 0.000 description 6
- 230000006870 function Effects 0.000 description 5
- 101000821096 Homo sapiens Synapsin-2 Proteins 0.000 description 2
- 102100021994 Synapsin-2 Human genes 0.000 description 2
- 238000004590 computer program Methods 0.000 description 2
- 238000005562 fading Methods 0.000 description 2
- 230000000994 depressogenic effect Effects 0.000 description 1
- 238000010348 incorporation Methods 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W88/00—Devices specially adapted for wireless communication networks, e.g. terminals, base stations or access point devices
- H04W88/02—Terminal devices
- H04W88/022—Selective call receivers
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L7/00—Arrangements for synchronising receiver with transmitter
- H04L7/0079—Receiver details
- H04L7/0083—Receiver details taking measures against momentary loss of synchronisation, e.g. inhibiting the synchronisation, using idle words or using redundant clocks
Definitions
- This invention relates to a radio receiver (pager) decoding system and a pager arranged to deploy said system.
- pager radio receiver
- One system producing a code format for use in wide area radio paging is outlined in Appendix A of A Standard Code for Radicpaging (A. report of the studies of the British Post Office Code Standardisation Advisory Group (POCSAG) 1578/1979.
- a radio receiver (pager ) decoding system arranged to receive a transmission signal that comprises a periodically recurring synchronization codeword separating first, second and subsequent batches of codewords in a plurality of frames, characterised in that the system has means for decoding after the receipt of an erroneous synchronization codeword or the loss thereof at its immediate specific decoding frame by virtue of the known time in the transmission between an obtained synchronization codeword immediately before the erroneous or lost synchronization codeword and said specific decoding frame immediately following said erroneous or lost synchronization codeword.
- decode operations are terminated after two consecutive erroneous synchronization codewords are received or lost and are not taken-up again until a synchronization codeword is correctly received.
- Figure 2 is a diagram s imilar to that of Figure 1 but showing a signal format with the receipt of an erroneous or the loss of a synchronization codeword (SC) and the ability of the system of the invention to decode.
- SC synchronization codeword
- Figure 3 is a block diagram showing an embodiment of a pager for incorporation of the system of the present invention.
- Figure 4 is a flow diagram of operations to be performed by one decoding circuit.
- Figure 5 is a detail flow diagram relating to a part of Figure 4.
- Figure 6 is a schematic.
- Figure 1 is shown the well known POCSAG signal format. in which a transmission comprises a preamble followed by batches of complete codewords, each batch beginning with a synchronisation codeword (SC).
- SC synchronisation codeword
- Each transmission starts with a preamble to permit a pager to attain bit synchronization and to prepare it to acquire word synchronization.
- the preamble is a pattern of reversals, 101010 ... repeated for a period of at least 576 bits, i.e. the duration of a batch plus a codeword.
- any batch codewords are transmitted comprising a synchronization codeword followed by 8 frames each containing 2 codewords. The frames are numbered 0 to 7 and the pager population is similarly
- Each pager is allocated to one of the 8 frames according to the 3 least significant bits (1sb) of its 21 bit identity and will only examine address codewords in that frame. Therefore each pager's address codewords must only be transmitted in the frame that is allocated to those codewords.
- Message codewords for any receiver may be transmitted in any frame but will follow, directly, the associated address codeword.
- a message may consist of any number of codewords transmitted consecutively and may embrace one or more batches but the synchronization codeword must not be displaced by message codewords.
- Message termination is indicated by the next address codeword or idle codeword. In any frame an idle codeword will be transmitted whenever there is no address codeword or message codeword to be transmitted.
- Preamble (P) commences and is followed by synchronization codeword SC and SC 2 , SC 4 ,
- SC 5 , SC 6 ; SC 3 and SC 7 are erroneous or lost owing to impulsive noise, but decoding is still achieved in the batch follcwir. ⁇ SC 3 , and SC 7 since both the respective decode frames are at predetermined time distance Z from SC 2 and SC 6 .
- a block diagram of a pager unit includes a decoding circuit.
- the radio pager comprises a receiver unit 10 having a binary detector 12, which is responsive to receiver 10 and is also responsive to a data enable signal from a microprocessor unit 20 over line 11 and which transmits received pulses to unit 20 over line 13.
- Unit 20 in one embodiment of the invention is an MC 146805 8-bit microprocessor by Motorola.
- an identity ROM read only memory
- program ROM program ROM
- support I.C. 26 The identity ROM 22 is programmed, using fusable links, for example, with the unique identity number of the specific pager.
- the identity number has two separate parts (1) a base identity code
- Each pager in the pager population is assigned one of eight possible frame numbers within a batch.
- the identity ROM 22 is plug-interchangeable.
- Each pager can respond to four different paging addresses and accordingly generates four distinguishable alerting tones.
- the four different paging addresses are calculated by the unit 20 utilising the base identity code contained in the identity ROM 22, as will be described in greater detail below.
- the program ROM 24 contains the computer program which controls the operation of the unit 20 to carry out the desired decoding functions of the decoding circuit.
- the portion of the computer program which specifically pertains to the decoding system of the present invention is attached hereto in source code form as given in
- the support I.C. 26 is a general purpose support circuit which, in the context of the present invention, performs three functions. First, it generates and regulates the secondary supply for the unit 20, the identity ROM 22, and the program
- ROM 24 contains a timer circuit known as the "deadman timer" (DMT), whose function is to reset the unit 20 after a predetermined interval in the event that a specific instruction either is not received or remains in the instruction register for an excessive period.
- DMT deadman timer
- Deadman timer is to prevent the decoder circuit from being held up in a lengthy software loop.
- the support I.C. 26 tests the primary power supply level on command and returns an indication of its condition.
- unit 20 generates the paging alert signals over line 27 to audio frequency amplifier 23 and ultimately transducer 30.
- a power supply switch 36 is responsive to an enable signal from unit 20 over line 35. When the power supply switch 36 is enabled, the receiver power suppiy is connected to receiver 10 and to binary detector 12 over line 37. Battery 40 provides the primary power supply.
- Switch 3S is a user-operated on/off switch.
- Switch 32 is a "cancel" switch, the closure of which cuts short a sounding paging alert.
- Switch 34 is a switch used to make a selection between "normal mode" and "memory mode”.
- the pager In “memory mode" upon receipt of a paging request the pager does not generate the paging alert, but it stores the page request in a memory allocated for such purpose in the unit 20.
- switch 34 When switch 34 is switched over to the "normal mode", or when the "cancel" switch 32 is depressed at any time, any page requests stored in memory are sequentially read out and their corresponding audible alerts (each uniquely distinguishable) are generated to the pager user.
- Word synchronization 2 checks the number of errors in the received synchronization codeword and if less than or equal to the error criterion clears the excess error flag and returns (122) (F) to decode. If the number of errors is greater than the prescribed error criterion then the flag is checked to see if it is already set (123). If clear the flag is then set (124) and the routine returns to decode. If the flag is already set (Y)(123), indicating that the previous synchronization word was received with excessive errors, the routine returns to the bit synchronization and transmission squelch routine (108) without decoding. Thus decode operations are terminated after two consecutive erroneous synchronization codewords have been received.
- the system of the invention gives decoding after the erroneous receipt or loss of one synchronization codeword (SC) such as SC 3 or SC 7 for example ( Figure 2) but will not give decoding if the noise and the loss extends to a second consecutive synchronization codeword and will then revert to the acceptance of the next synchronization codeword (SC) that is obtained correctly, this is shown schematically in Figure 6.
- SC 1 is correct and decode occurs at d 1 .
- SC 3 is lost and there are too many erronious synchronization codewords to give a decode at X.
- SC 4 is correct and decode occurs at d 3 .
Landscapes
- Engineering & Computer Science (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Mobile Radio Communication Systems (AREA)
Abstract
Systeme de decodage faisant partie d'une unite de recherche de personnes radio-portative pouvant detecter et stocker jusqu'a quatre signaux differents d'alarme par utilisateur. Chaque dispositif de recherche peut etre adresse individuellement. Le systeme de decodage est sensible a un protocole de transmission dans lequel le signal de transmission comprend une position de synchronisation permettant la synchronisation par bit, un mot de code de synchronisation recurrent, et un ou plusieurs mots de codes d'adresses a l'interieur d'un lot de mots de code transmis entre chaque mot de code de synchronisation, un mot de code de synchronisation recurrent separant le premier, le deuxieme et les lots successifs de mots de code dans une pluralite de blocs, le systeme se caracterisant en ce qu'il possede des organes pour le decodage apres la reception d'un mot de code de synchronisation incorrect ou de la perte de celui-ci a son bloc de decodage specifique immediat grace au laps de temps connu s'etant ecoule dans la transmission entre un mot de code de synchronisation obtenu immediatement avant le mot de code de synchronisation incorrect ou perdu et le bloc de decodage specifique suivant immediatement le mot de code de synchronisation incorrect ou perdu.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB8118532810616 | 1981-06-16 | ||
GB8118532A GB2100486B (en) | 1981-06-16 | 1981-06-16 | Radio receiver (pager) decoding system |
Publications (1)
Publication Number | Publication Date |
---|---|
WO1982004514A1 true WO1982004514A1 (fr) | 1982-12-23 |
Family
ID=10522553
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/GB1982/000160 WO1982004514A1 (fr) | 1981-06-16 | 1982-05-28 | Systeme ameliore de decodage de recherche de personnes |
Country Status (4)
Country | Link |
---|---|
EP (1) | EP0080467A1 (fr) |
JP (1) | JPS58501487A (fr) |
GB (1) | GB2100486B (fr) |
WO (1) | WO1982004514A1 (fr) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0084889A2 (fr) * | 1982-01-27 | 1983-08-03 | Nec Corporation | Récepteur d'appel radio numérique |
Families Citing this family (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB2136178A (en) * | 1983-02-25 | 1984-09-12 | Philips Electronic Associated | Pager decoding system |
JP2725480B2 (ja) * | 1991-06-25 | 1998-03-11 | 日本電気株式会社 | 無線選択呼出受信機 |
GB9424438D0 (en) * | 1994-12-02 | 1995-01-18 | Philips Electronics Uk Ltd | Fade recovery in digital message transmission systems |
JP2699956B2 (ja) * | 1995-10-30 | 1998-01-19 | 日本電気株式会社 | 無線選択呼出受信機 |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB1122195A (en) * | 1964-11-13 | 1968-07-31 | Thomson Houston Comp Francaise | System for processing synchronous digital information signals |
GB2086106A (en) * | 1980-10-13 | 1982-05-06 | Motorola Ltd | Pager Decoding System with Intelligent Synchronisation Circuit |
-
1981
- 1981-06-16 GB GB8118532A patent/GB2100486B/en not_active Expired
-
1982
- 1982-05-28 WO PCT/GB1982/000160 patent/WO1982004514A1/fr not_active Application Discontinuation
- 1982-05-28 JP JP50160982A patent/JPS58501487A/ja active Pending
- 1982-05-28 EP EP19820901529 patent/EP0080467A1/fr not_active Ceased
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB1122195A (en) * | 1964-11-13 | 1968-07-31 | Thomson Houston Comp Francaise | System for processing synchronous digital information signals |
GB2086106A (en) * | 1980-10-13 | 1982-05-06 | Motorola Ltd | Pager Decoding System with Intelligent Synchronisation Circuit |
Non-Patent Citations (1)
Title |
---|
IEEE Transactions on Vehicular Technology, Vol. VT-30, No. 2, May 1981 (New York, US) P.J. MABEY: "Digital Signaling for Radio Paging", pages 85-94, see page 85, left-hand column, line 40 - page 86, right-hand column, line 49 * |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0084889A2 (fr) * | 1982-01-27 | 1983-08-03 | Nec Corporation | Récepteur d'appel radio numérique |
EP0084889A3 (en) * | 1982-01-27 | 1983-08-10 | Nec Corporation | Digital radio paging receiver |
Also Published As
Publication number | Publication date |
---|---|
GB2100486A (en) | 1982-12-22 |
JPS58501487A (ja) | 1983-09-01 |
GB2100486B (en) | 1985-02-20 |
EP0080467A1 (fr) | 1983-06-08 |
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