EP0554941A1
Expired / Lapsed
EP
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Battery power conservation in a selective call system
Assignee: Philips Electronics UK Ltd
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Filing: 1993-01-27
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Granted: —
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Expires: 2013-01-27
Abstract
Abstract Selective call systems such as the CCIR Radiopaging Code No. 1 (or POCSAG) has a signal format giving an inherent battery power conservation duty cycle of 1:8 requiring a bit synchronised pager to energise its receiving section to receive the synchronisation codeword and again for the duration of its assigned frame in each batch. For those pagers wanting to operate in accordance with a longer duty cycle, successive superbatches of N batches are created and the pager is assigned to say one frame only of the superbatch. However in order to obtain synchronisation in the superbatch, a predetermined codeword (PCW) is transmitted in the first frame of the first batch of the N batches. A pager which has achieved batch and superbatch synchronisation de-energises its receiving section until its assigned frame. The transmission of a predetermined codeword once in every N batches is transparent to the pagers operating the 1:8 duty cycle and also facilitates recovery of superbatch synchronisation in deep fade and carrier lost situations.
Inventors
- 👤 Anthony Keith c/o Philips Telecom Sharpe
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-04 20:58
CPC Classifications
H; H04; H04W; H04W52/00; H04W52/02; H04W52/0209; H04W52/0225; H04W52/0229; H04W84/00; H04W84/02; H04W84/022; H04W88/00; H04W88/02; H04W88/022; Y; Y02; Y02D; Y02D30/00; Y02D30/70
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
184 words
A selective call system comprising a base station and a plurality of receivers, wherein the base station transmits signals in accordance with a signal format including a succession of batches, each batch commencing with a synchronisation codeword followed by a predetermined integer number, n, of frames, each frame having a duration corresponding to the transmission of at least one receiver identity code, each receiver comprising a receiving section and a control section which includes means for controlling the energisation of the receiving section, characterised in that the base station in every 1 in N batches, where N is an integer of at least 2, transmits a predetermined codeword in a preselected one of the n frames, and in that at least one of the receivers is controlled by its control section to energise its receiving section to receive said predetermined codeword, said control section in response to receiving said predetermined codeword de-energising said receiving section for a predetermined period and thereafter re-energising said receiving section for a duration corresponding to at least one frame in at least one predetermined batch of said N batches.
Claim 2
Dependent Claim
31 words
A system as claimed in claim 1, characterised in that said predetermined codeword is transmitted in the frame immediately following the synchronisation codeword transmitted in a first of said N batches.
Claim 3
Dependent Claim
81 words
A system as claimed in claim 1 or 2, characterised in that each frame has a duration corresponding to the transmission of at least two receiver identity codes, in that the base station transmits identity codes in an ordered sequence and in that the control section of a receiver in response to determining that an identity code being transmitted follows the transmission of its own identity code in the sequence de-energises its receiving section prior to the expiry of its frame.
Claim 4
Dependent Claim
84 words
A system as claimed in claim 1 or 2, characterised in that receivers operating different battery conservation regimes are assigned to respective groups, in that the identity codes of the receivers in each of said groups has a prefix which is unique to that group, and in that the control section of a receiver in response to determining that the prefix of an identity code being transmitted does not correspond to its group de-energises its receiving section prior to the expiry of its frame.
Claim 5
Independent Claim
32 words
A system as claimed in any one of claims 1 to 4, characterised in that groups of receivers operating the same type of battery power conservation regime are assigned to different batches.
Claim 6
Dependent Claim
156 words
A selective call receiver for use in the system as claimed in claim 1, the receiver comprising a receiving section and a control section, said control section including means for storing a synchronising codeword, an identity codeword and a predetermined codeword which is used by the control section to operate the receiver in accordance with a predetermined battery power conservation regime, and timing means for controlling the energisation of the receiving section, whereby in response to the control section detecting receipt of said predetermined codeword, the receiving section is de-energised until the expiry of a first predetermined time period after which it is energised for the duration of a frame and thereafter it is de-energised until the expiry of a second predetermined period whereat the receiving section is energised to receive the synchronisation codeword of the batch containing said predetermined codeword, the sum of said first and second predetermined periods exceeding the duration of a batch.
Claim 7
Dependent Claim
73 words
A selective call receiver as claimed in claim 6, for use in a system in which identity codes are transmitted in an ordered sequence, characterised in that the control section comprises means for determining whether an identity code as received is after its own assigned identity code in the ordered sequence, and in response to determining that it is, the control section de-energises the receiving section prior to the expiry of the frame.
Claim 8
Dependent Claim
78 words
A selective call receiver as claimed in claim 6, for use in a system in which receivers which operate a particular battery conservation regime are assigned identity codes including a prefix unique to those receivers, characterised in that the control means comprises means for determining the presence of said prefix in a received identity code and in response to determining that it is absent, the control section de-energises the receiving section prior to the expiry of the frame.
References Cited (Backward Citations)
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