RECEIVER POWER CONSUMPTION REDUCTION

Abstract: There is a time multiplex (TM) of data blocks (FI, DO), some of which are fillers (FI) not containing any useful information. A controller (CON) forces receiver circuitry (RC) into a low-power mode (PWR &darr& ) during the fillers (FI). To that end, the controller (CON) is programmed to carry out the following steps. The controller (CON) detects (DTS) successions (SC) of a filler (FI) by a data block (DO) of another type. It measures (MSR) a minimum time (Tmin) between the successions (SC). When the controller detects (DTF) a filler FI, it forces (FRC) the receiver circuitry (RC) into the low-power mode (PWR &darr& ) until the minimum time (Tmin) since the most recently detected succession (SC(n)) has expired. Such a reduction of power consumption is relatively easy to implement because it does not require any special messages for indicating numbers of consecutive fillers.

Description: Receiver power consumption reduction. FIELD OF THE INVENTION The invention relates to reducing power consumption of a receiver of the following type. The receiver is capable of receiving a time multiplex of data blocks, some of which are fillers not containing any useful information. BACKGROUND ART CA-A-2, 194,316 describes a cellular telecommunications system. It includes at least one base station and at least one user terminal that is bidirectionally coupled to the at least one base station through a RF interface. The system further includes system circuitry for composing messages and transmitting composed messages continuously over a forward RF link to the at least one user terminal. The messages include filler messages and other messages, and the circuitry composes the messages for specifying in a transmitted message a number of filler messages that will be transmitted consecutively. The user terminal includes a receiver for receiving messages from the forward RF link and circuitry for determining a number of consecutive filler messages that will be transmitted. The user terminal further includes a controller that is responsive to a received message for placing the user terminal in a powered-down state for a period of time that is a function of the number of consecutive filler messages. SUMMARY OF THE INVENTION It is an object of the invention to facilitate a reduction of power consumption of a receiver of the above-identified type. The invention takes the following aspects into consideration. A reduction of power consumption can be achieved by forcing receiver circuitry into a low-power mode during a series of fillers. When the receiver circuitry is the low-power mode, reception will generally be poor, or even not possible at all. For that reason, it should be ensured that the low-power mode has ended when a data block of another type occurs. If not, useful information may be lost. A basic problem is how to timely end the low-power mode One solution is to establish the instance at which a seπes of fillers ends Since reception will be poor in the low- power mode, it will generally not be possible to establish this instance by directly detecting the end of the seπes of fillers. For that reason, the instance at which a seπes of fillers ends should be known beforehand. In the pπor art, the basic problem descπbed above is solved by providing, m the multiplex of data blocks received, a message indicating the number of fillers that will follow A disadvantage of this solution is as follows To make it generally work, a large number of base station operators and manufacturers must agree upon the form of the message and, in addition, how and where it should be inserted into the multiplex of data blocks. That is, standardization is required. This will be hard to achieve, if not impossible, because the parties who should agree upon a single standard are each other's competitors. In the invention, at a receiving end, a controller detects successions of a filler by a data block of another type. It measures a minimum time between the successions. When the controller detects a filler, it forces the receiver circuitry into the low-power mode until the minimum time since the most recently detected succession has expired. In effect, the controller observes the multiplex of data blocks received. The controller does so to deπve a cπteπon for re-activatmg the receiver circuitry when it has been forced into the low-power mode. Accordingly, the invention does not require special messages for indicating numbers of fillers That is, it does not require any special standardization for timely ending a low-power mode duπng fillers Thus, the invention facilitates a reduction of power consumption. With regard to the extent to which power consumption can be reduced, the following remarks are made In pπnciple, the invention will perform somewhat less than the pπor art. This is because, in the pπor art, the instant at which a seπes of fillers will end is known beforehand. Thus, it is possible to maintain the low-power mode until this very instant, or just before it. In the invention, the instant at which a seπes of fillers ends, is not known beforehand. Rather, m effect, the earliest possible instant at which the seπes of fillers might end, is established. The earliest possible instant is when, since the most recently detected succession of a filler and a data block of another type, the measured minimum time between such successions has expired The low-power mode is maintained until this earliest possible instant which need not be the actual instant at which the seπes of fillers will end. In that case, the receiver circuit will be re-activated, whereas the seπes of fillers has not yet ended. In practice, the invention will perform comparably to the pπor art with regard to the extent to which power consumption can be reduced Many data transmissions have a frame-like structure with clusters of different data blocks in a particular order. ~Any fillers are often placed at the end of a cluster. Generally, the clusters do not substantially vary in length of time or may even have a fixed length of time. This implies that there will be relatively little variation in time between successions of a filler and a data block of another type. Consequently, the earliest possible instant at which a series of fillers might end, which instant the invention in effect establishes, as described above, to re-activate the receiver circuitry, will generally be close to the actual instant at which the series of fillers ends. Thus, for a series of fillers, the invention will generally force the receiver circuitry into the low-power mode for a duration which substantially corresponds to the duration of the series of fillers. The invention and additional features, which may be optionally used to implement the invention to advantage, are apparent from and elucidated with reference to the drawings described hereinafter. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a conceptual diagram illustrating features of the invention as claimed in claim 2; Fig. 2 is a block diagram illustrating an example of a mobile phone in accordance with the invention; Fig. 3 is a timing diagram illustrating a baseband signal in the mobile phone illustrated in Fig. 2; and Fig. 4 is a flow-chart illustrating a method in accordance with which the receiver illustrated in Fig. 2 may operate. DETAILED DESCRIPTION OF THE DRAWINGS First, some remarks will be made on the use of reference signs. Like entities are denoted by like letter codes throughout the drawings. In a single drawing, various similar entities may be shown. In that case, a numeral is added to the letter code, to distinguish similar entities from each other. The numeral will be between parentheses if the number of similar entities is a running parameter. In the description and the claims, any numeral in a reference sign may be omitted where appropriate. Fig. 1 illustrates the following features. There is a time multiplex TM of data blocks FI, DO, some of which are fillers FI not containing any useful information. A controller CON forces receiver circuitry RC into a low-power mode PWRi during the fillers FI. To that end, the controller CON is programmed to carry out the following steps. The controller CON detects DTS successions SC of a filler FI and a data block DO of another type. It measures MSR a minimum time Tmin between the successions SC. When the controller detects DTF a filler FI, it forces FRC the receiver circuitry RC into the low-power mode PWRi until the minimum time Tmin since the most recently detected succession SC(n) has expired. Fig. 2 illustrates an example of a mobile phone in accordance with the invention. The mobile phone comprises a receiver circuit REC, a micro-controller UC, and two timers TIMl, TIM2. The receiver circuit REC receives a radio signal RF from a base station, not shown in Fig. 2. In response, the receiver circuit REC provides a baseband signal BB which is a time multiplex of different messages, a message being a data block having a particular function. The micro-controller UC receives the baseband signal BB and is able to recognize the different messages and to distinguish one from the other. The micro-controller UC is able to reset and start each timer TIM and to read timer-values contained in the timers T . Fig. 3 illustrates an example of the baseband signal BB which is a control forward channel in accordance with the AMPS mobile phone specification EIA-553. The baseband signal BB comprises system parameter messages SP, global action messages GA, registration identification messages ID, mobile control messages MC and control filler messages CF. In the baseband signal BB illustrated in Fig. 3, there are clusters C of messages SP, GA, ID, MC. A cluster C begins with a system parameter message SP and may end with one or more control filler messages CF. Fig. 4 illustrates a method in accordance with which the mobile phone illustrated in Fig. 2 may operate. The method comprises three phases: a verification phase VER in which steps S1-S7 are carried out, a receiver-control phase RCO in which steps S8- S12 are carried out, and an idle phase IDL. The verification phase VER is, in effect, an examination of the baseband signal BB to find out what structure it has. Depending on the structure, the verification phase VER is either succeeded by the receiver-control phase RCO or by the idle phase DDL. In the receiver-control phase RCO, the micro-controller UC forces the receiver circuit REC into a low-power mode when the radio signal RF conveys control filler messages CF. In the idle phase IDL, the micro-controller UC does not force the receiver circuit REC into the low-power mode. In any case, the verification phase VER starts when the mobile phone switches from one channel to another. The verification phase VER will now be described in more detail. In step SI, the micro-controller UC first resets and subsequently starts the timer TIMl; TIMl: RST+STRT. It waits for a succession of a control filler message CF and a system parameter message SP to occur and then resets and starts the timer TIM2; TIM2: RST+ST RT. In step S2, the micro controller UC checks whether a succession of a control filler message CF and a system parameter message SP occurs. If, it does, Y, steps S3 and S4 are carried out prior to step S5. If it does not, N, step S5 is directly carried out, thus bypassing steps S3 and S4. In step S3, the micro-controller UC reads a timer value TV2 contained in the timer TIM2, resets and starts the timer TIM2. In step S4, the timer value TV2 is compared with a previously read timer value TV2p which has been retained to represent a minimum time Tmin; Tmin=MIN(TV2,TV2p). The smaller of the two timer values TV is kept to represent the minimum time Tmin between two successions of a control filler message CF and a system parameter message SP. In step S5, the micro-controller UC updates a message-order list MOL defining which types of messages have occurred over a recent period; UPD(MOL). That is, it examines in which order the different types of messages occur. In step S6, the micro-controller UC checks, on the basis of the message-order list MOL, whether a control filler message CF has directly been followed by a global action message GA, a registration identification ID message, or a mobile control message MC; CHK(MOL):CF-GA/CF-ID/CF-MC? If it has, Y, the method proceeds to the idle phase EDL. If it has not, N, step S7 is carried out. In this step, the micro-controller UC checks whether the timer TIMl has a timer value TV2 which is below a predefined threshold LIM representing a time-limit for the verification phase VER. If it has not, N, step S2 is carried out anew, as well as any subsequent steps. Thus, the method remains in the verification phase VER. If the outcome of this check is yes Y, the method proceeds to the receiver-control phase RCO. The receiver-control phase RCO will now be described in greater detail. In step S8, the micro-controller UC waits for a succession of a control filler message CF and a system parameter message SP to occur and then resets and starts the timer TIM2. In step S9, the micro-controller UC checks whether a control filler message CF occurs. If it does, Y, step S10 is carried out. If it does not, N, step S9 is repeated. In step S10, the micro-controller UC switches off the receiver circuit REC; REC:OFF. In step SI 1, the micro-controller UC checks whether the timer TIM2 has a timer value TV2 that is below the minimum time Tmin described hereinbefore. If it has, Y, step S 11 is repeated. If it has not, N, step S 12 is carried out. In this step, the micro-controller UC switches on the receiver circuit REC; REC:ON, and subsequently again carries out step S8 and any following steps. With regard to step S9, the following remarks are made. Messages other than control filler messages CF, may comprise one or more control filler words in addition to another word. A message that has such a composition is a so-called multi-word message. In step S9, the micro-controller UC can do a twofold check: a first check to see if a control filler word occurs and, if so, a second check to see if it is part of a multi-word message. If the control filler word is part of a multi-word message, there is no control filler message and, consequently, step S9 is repeated. The drawings and their respective descriptions illustrate rather than limit the invention. It will be evident that there are numerous alternatives which fall within the scope of the appended claims. In this respect, the following closing remarks are made. Although, in accordance with Fig. 4, the micro-controller UC carries out the steps S 1-S 11 for reducing power-consumption, this does not exclude the micro-controller UC carrying out other steps for other tasks. For example, in steps S1,S2,S8,S9,S11, the microcontroller UC is, in effect, waiting for something to occur. During that time, the microcontroller UC may carry out other tasks, thus, operate in a multi-tasking mode. There are numerous ways of physically spreading functions or functional elements over various units. In this respect, the drawings are very diagrammatic, each representing only one possible embodiment of the invention. Thus, although a drawing shows different functional elements as different blocks, this by no means excludes that some functional elements, or all functional elements, may be implemented as a single physical unit. Although, in Fig. 2, the timers T Ml and TEVI2 are illustrated by means of blocks separate from the micro-controller UC, this does not exclude the timers being incorporated in the micro-controller. Finally, for forcing the receiver circuitry in the low-power mode, the following method may also be applied. The controller measures a minimum time between the occurrence of a data block of a certain type not being a filler, and an occurrence of a data block directly succeeding a filler, but not itself being a filler. The controller detects an occurrence of a data block of the certain type. It subsequently detects an occurrence of a filler and, in response thereto, forces the receiver circuitry into the low-power mode until the minimum time since the occurrence of the data block of the certain type has expired. Thus, this method, which also falls within the scope of the invention, allows the use of a time-reference other than a succession of a filler and a data block of another type as illustrated in Fig. 1.

Claims: CLAIMS: 1. A receiver for receiving a time multiplex (TM) of data blocks (DO,FI) some of which are fillers (FI) not containing any useful information, the receiver comprising a controller (CON) for forcing receiver circuitry (RC) into a low-power mode (PWRi) during the fillers (FI); characterized in that the controller (CON) is programmed to carry out the following steps: monitoring the time multiplex (TM) of data blocks (DO,FI) so as to derive a minimum time (Tmin) between a certain event in the time multiplex (TM) of data blocks (DP,FI) and a succession of a filler (FI) and a data block (DO) of another type; detecting (DTF) a filler (FI); and, in response thereto, - forcing (FRC) the receiver circuitry (RC) into the low-power mode (PWR-l) until the minimum time (Tmin) has expired since the certain event that has most recently occurred. 2. A receiver for receiving a time multiplex (TM) of data blocks (DO,FI) some of which are fillers (FI) not containing any useful information, the receiver comprising a controller (CON) for forcing receiver circuitry (RC) into a low-power mode (PWR ) during the fillers (FI); characterized in that the controller (CON) is programmed to carry out the following steps: detecting (DTS) successions (SC) of a filler (FI) and a data block (DO) of another type; measuring (MSR) a minimum time (Tmin) between the successions (SC); detecting (DTF) a filler (FI); and, in response thereto, forcing (FRC) the receiver circuitry (RC) into the low-power mode (PWRi) until the minimum time (Tmin) since the most recently detected succession (SC) has expired. 3. A method of receiving a time multiplex (TM) of data blocks (DO.FI) some of which are fillers (FI) not containing any useful information, the method comprising the step of forcing receiver circuitry (RC) into a low-power mode (PWR ) during the fillers (FI); characterized in that the method comprises the following steps: o monitoπng the time multiplex (TM) of data blocks (DO,FI) so as~to deπve a minimum time (Tmin) between a certain event in the time multiplex (TM) of data blocks (DP,FI) and a succession of a filler (FI) and a data block (DO) of another type, detecting (DTF) a filler (FI), and, in response thereto, - forcing (FRC) the receiver circuitry (RC) into the low-power mode (PWRi) until the minimum time (Tmin) has expired since the certain event that has most recently occurred. 4. A method of receiving a time multiplex (TM) of data blocks (DO,FI) some of which are fillers (FI) not containing any useful information, the method compπsmg the step of forcing receiver circuitry (RC) into a low-power mode (PWRi) duπng the fillers (FT); characteπzed in that the method compπses the following steps: detecting (DTS) successions (SC) of a filler (FT) and a data block (DO) of another type; - measuπng (MSR) a minimum time (Tm ) between the successions (SC); detecting (DTF) a filler (FI); and, in response thereto, forcing (FRC) the receiver circuitry (RC) into the low-power mode (PWRl) until the minimum time (Tm ) since the most recently detected succession (SC) has expired.

Inventors: TARVAINEN TUOMO, TARVAINEN, TUOMO
Applicants: KONINKL PHILIPS ELECTRONICS NV, KONINKLIJKE PHILIPS ELECTRONICS N.V.
Application year: 1999
Main classification: H04B1
IPC codes: H04B1, H04B7