FI106179B - Method and arrangement for utilising the channel in a cellular radio system - Google Patents

Description

106179

The present invention relates generally to the provision of communication between channels of base stations and terminals of a cellular radio system. In particular, the invention relates to efficient utilization of the data transfer capacity contained in the channels.

According to the official definition of CCITT (Comite Consultatif International Telephonique et Telegraphique), a '' channel 'is an identified portion of an interface. In cellular radio systems, the radio interface between the base station and the terminals 10 includes a plurality of channels. Of these, the downlink paging channel, the general control channel, and the cellular general transmission channel are significant for the present invention. In order to clarify the background of the invention, the following describes the known implementation of these channels in the Global System for Mobile telecommunications (GSM) system.

In the GSM system, the radio interface is divided into 200 kHz wide frequency bands from which time slots of 0.577 ms are separated in time, where information is transmitted in bursts. Defining a particular channel means indicating the time intervals at which information belonging to that channel may be transmitted. The paging CHannel (PCH) and the Access 20 Grant CHannel (AGCH) form the PAGCH entity, in which the division between the PCH and the AGCH changes over time. The Broadcast Control CHannel (BCCH) is its own channel. The available time slots of the BCCH and the PAGCH are defined as follows: On the CCCH (Common Control CHannel) frequency, 51 consecutive frames of eight consecutive time slots are taken and the first time slot of each frame. The 51 time slots thus obtained are numbered from 0 to 50. In this case, slots numbered 2-5 belong to BCCH and slots 6-9, 12-15, 16-19, 22-25, 26-29, 32-35, 36-39, 42-45 and 46-49 belong to PAGCH if you have a so called full speed PAGCH. The third -.... peuden PAGCH includes only slots 6-9, 12-15, and 16-19.

The cellular broadcast channel, or CBCH (Cell Broadcast CHannel), may be on the same frequency as the BCCH and the PAGCH, or may be on a frequency hopping basis. It is defined such that when looking at eight consecutive 51 frame periods of approximately 2 seconds in total, the CBCH comprises four groups of four time slots during this time. 35 The time slots used by the CBCH are spaced from the time slots used by the PAGCH so that there is always at least a minimum time difference between the burst transmitted in the CBCH slot and the burst included in the paging message within the PAGCH slot, so that the terminal can receive both bursts sent by the CBCH and the paging messages. The organization of time slots for BCCH, 5 PAGCH, and CBCH is described in more detail, for example, in Michel Mouly, Marie-Bemadette Pautet, '' The GSM System for Mobile Communications', published by the authors, ISBN 2-9507190-0-7 , Palaiseau 1992.

Not all terminals in a given cell receive all paging messages sent by PAGCH, but the terminals are divided into so-called. paging groups to which invitations to send have a specific schedule within the PAGCH. When the terminal is in idle mode, its receiver is turned on and tuned to the CCCH frequency whenever its paging group has scheduled call sending time. In addition, the receiver of the idle terminal is on and tuned to the CCCH frequency at all times during the BCCH and the CBCH.

The receiver of the terminal consumes electrical energy when switched on. The receiver should be on for as little time as possible in order to charge the terminal battery longer.

It is an object of the present invention to provide a method by which the power consumed by the receiver of an idle terminal 20 can be reduced compared to the prior art. It is also an object of the invention to provide devices for using the method according to the invention.

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The object of the invention is achieved by placing such information, which is generally transmitted on the general control channel and the cell's general transmission channel, in the free portions of the paging channel.

The method of the invention is applicable to a cellular radio system in which a paging channel is defined between the base station and the terminal for transmitting downlink requests and a common control channel for generic base station • ·.

man cell information. The method of the invention is characterized in that generic base station cell information is transmitted over a paging channel when the paging channel's communication capacity is greater than the sum of the downlink connection requests to be transmitted.

3, 106179

The invention also relates to a base station in a cellular radio system, characterized in that it comprises means for transmitting general cellular information about the base station on a paging channel.

The invention further relates to a terminal for a cellular radio system, characterized in that it comprises means for receiving general cellular information about the base station on the paging channel.

The paging channel comprises certain time slots (more generally, certain periods of time on a particular frequency) during which the terminals must be in reception, regardless of whether the base station is actually sending paging messages or not. According to the invention, the base station may transmit other information in those parts of the paging channel that would otherwise be blank due to the small number of paging messages being transmitted. The other information is most preferably the information that is normally transmitted on the general control channel and / or the cell's general transmission channel. When a terminal receives data from a common control channel and / or a cellular broadcast channel on a paging channel, it does not need to re-receive the same information on the actual common control channel and / or cellular broadcast channel, but can shut down its receiver while transmitting other channels.

In the base station, power saving is not as essential as in the terminals, so the base station may well transmit the same information in both the paging channel blank portions 20 and the general control channel and / or the general cell broadcast channel.

The invention will now be described in more detail with reference to exemplary preferred embodiments and the accompanying drawings, in which: FIG. 1 illustrates the principle of the invention, FIG. 2 illustrates a call message structure known per se, FIG. 3 illustrates call location on a paging channel. a cellular radio system terminal according to the invention.

In the pictures, the same reference numerals are used for like parts.

In Figure 1, block 100 generally depicts fixed parts or "30" network "of a cellular radio system and block 101 depicts a terminal. The network 100 has some functional part 102 which provides transmission control information, which in connection with the GSM system 4,106,179 is referred to as BCCH information. Similarly, the network 100 has a functional section 103 that generates general Broadcast Information, or CBCH information, and a functional section 104 that generates Invitation Messages, or PCH information. The terminal 101 has a system parameter memory 105 for storing received BCCH information. In addition, the terminal 5101 has a general broadcast presentation section 106 for displaying messages according to the CBCH information to the terminal user, and a paging message processing unit 107 which examines whether the received invitation message is for the terminal itself and, if so, initiates the The network 100 and the terminal 101 are connected by three channels 108, 109 and 110 which comply with the specifications of the cellular radio system in question. In the GSM ice system, the BCCH channel 108, the CBCH channel 109, and the PCH channel 110 are comprised of certain cycles according to a cyclically repeated definition at a CCCH frequency, as noted above in the prior art description.

In network 100, each of the functional sections 102, 103 and 104 always has a direct connection to 15 corresponding channels 108, 109 and 110, so that the information produced by each functional section 102, 103 and 104 is transmitted on their respective channel. On the other hand, the functional parts 102 and 103 constituting the BCCH information and the CBCH information also have a connection to the PCH channel 110, but these connections are conditional: the BCCH information and / or the CBCH information is transmitted on the PCH channel only when there is space. The paging messages generated by the PCH section 104 do not occupy all space on the PCH channel 110.

The terminal 101 has a connection from the PCH channel 110 to the paging message processing block 107. In addition, the PCH channel 110 has a conditional connection to the system parameter memory 105 and the general broadcast presentation section 106 to direct its associated data received on the PCH channel to the correct destination. The connections from the BCCH channel 108 to the system parameter memory 105 and the CBCH channel 109 to the general broadcast presentation section 106 are also contingent, i.e. they are used only when the required information is not received for the blocks 105 and 106 via the PCH channel 110.

Figure 2 shows an invitation message as defined in the GSM system standard number GSM 04.08. The first field of the invitation message 200 is the so-called. pseudo-length 201, which is one octet or eight bits. The apparent length value in field 201 represents the sum of the lengths of the other fields 203 between the first field 201 and the last field 202 of the invitation message. 203 is irrelevant to the invention and their total length, i.e., the apparent length value, can vary from five to 22 octets. The last field 202 is a so-called rest octets field and its length is determined by its length and the apparent length in field 201 The sum of the values of 5 106179 den should be 22 octets, that is, the length of the field 202 of the residual octets may be any integer octets between zero and 17 octets *, including these values.

The above-mentioned field lengths are related in particular to the so-called. type 1 invitation message. Standard Stan-5 GSM 04.08 also defines type 2 and type 3 call messages, which differ from the type 1 call message in terms of field length and purpose. However, they also have a field of residual octets that can be used in a manner according to an embodiment of the invention described below.

The use of residual octet field 202 is reserved for future extensions of system 10 in GSM 04.08. The invention is one such extension. According to the prior art, the base station could send the paging message as shown in Figure 2, which contains five octets of actual information in fields 203 and seventeen octets of fill space, i.e., empty space, in field 202. According to a first embodiment of the invention, the empty space remaining in the field 202 can be utilized by transmitting information that would normally be transmitted on a BCCH or CBCH.

In order for the terminals to know that, in a particular paging message, the residual octet field 202 contains information belonging to other channels, that paging message must include some identifier to that effect. One way to create the tag is to use the Message Type field included in the fields 203, which is not shown separately in Figure 20 and has a length of one octet. Eight bits can uniquely define 256 different types of messages, but at the time of filing this patent application, barely a hundred Message Type field values are reserved for certain types of messages (e.g., 00100001 means type 1 invitation message, value 00100010 means type 2 invitation message, value 001001 3 25 invitation messages and the value 00100111 represents the response to the invitation message). An unallocated value of the Message Type field may be reserved to refer to an invitation message whose residual octet field contains information that would normally belong to the BCCH. Another not yet assigned value of the Message Type field may be reserved to refer to a p * call message, whose residual octet field contains information that would normally belong to the * '30 CBCH.

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Another possible way to determine the identifier of the call message which indicates that the residual octet field contains information from other channels is to use the excess capacity included in the field 201. The call message 200 has a maximum apparent length of 22 octets, so that the maximum value of field 201 is a binary number 00010110 corresponding to a number 22 of the decimal system 35. Thus, the three most significant bits of field 201 in prior art call messages are always zeros. To use them in the manner of the invention, it can be determined, for example, that the most significant bit of field 201 is 1 if the residual octet field contains information that would normally belong to the BCCH, and the second most significant 5 bit of field 201 is 1 if the residual octet field contains information would belong to the CBCH.

Fig. 3 schematically shows the time slots 301 belonging to the paging channel, which, for example, are 36 in the full rate PAGCH of the GSM system during 51 consecutive frames. The number of downlink invitation messages and capacity allocation messages sent in response to the uplink invitation messages sent by the terminals 10 varies according to how often users call each other. During a quiet period, it may be that only a few of the 36 time slots contain an invitation message or a capacity allocation message. These "full" time slots are shown in gray, and it may even be that several 51 frame periods are consumed so that the base station does not send any paging messages or capacity allocation messages. In this case, most of the time slots 301 are empty slots shown in white. According to another embodiment of the invention, the base station may transmit similar messages that it transmits on the BCCH and the CBCH according to the prior art in these empty time slots This embodiment may be alternate to using the residual octet fields of the paging messages shown in FIGURE 2, or both embodiments may be applied simultaneously. the advantage of using residual octet fields is that there is no need to define any new identifiable message, but that messages of the prior art can be used per se, and please only broadcast on a different channel than f 25 in the prior art system.

Fig. 4 schematically shows a base station 400 of a cellular radio system that communicates with other parts of the network via a bidirectional communication link 401 in a manner known per se. Base station 400 comprises parallel transmitting portions 402 for establishing simultaneous transmissions at different frequencies. One of the transmit portions 402 30 is a Cell Common Control Frequency or CCCH Transmit portion containing a BCCH portion 403, a CBCH portion 404, and a PCH portion 405, and a mutual scheduling portion 406 thereof, which receives synchronization information from a generic control block of the base station for scheduling. 407. Parts 403, 404, and 405 each form messages according to their own channel specifications. In the order determined by timing section 35 406, sections 403, 404, and 405 each alternate with radio frequency section 408, which performs the necessary modulation and up-mixing to convert the transmitted messages to a CCCH frequency signal from a near-406 antenna 409. and the CBCH portion 404 communicates with the PCH portion to provide information normally transmitted on the BCCH. 11a or CBCH, may be placed in the residual octets of the call messages generated in the PCH portion. Another embodiment of the invention requires the scheduling section 406 to be programmed to allow the BCCH section 403 or CBCH section 404 to connect to radio frequency section 408 when the PCH section 405 does not have paging messages to be transmitted in all PCH slots. The PCH part 405 may have a connection to the timing part 406 through which the PCH part can detect when the PCH has extra space. Alternatively, the BCCH section 403 and the CBCH section 10 404 may provide information to the PCH section 405 continuously, whereby the PCH section 405 will only ignore this information if the PCH has no space to send it. Naturally, the base station of a cellular radio system may have a plurality of components other than those shown in Figure 4.

Figure 5 schematically illustrates a cellular radio system terminal 500, of which 15 are antenna 501, radio frequency section 502, channel decoding and demultiplexing section 503, video controller 504 and display 505, D / A converter 506 and speaker 507 and radio block 508. a receiver whose activation and reception frequency can be controlled by control block 508. The channel decoding and demultiplexing section 503 directs the audio signal 20 during the call through the D / A converter 506 to the loudspeaker 507 and all data signals to the control block 508, from which text messages received on the CBCH channel are further directed to the display 505 by the video controller 504. in prior art operation, control block 508 switches the receiver included in radio frequency section 502 to receive at a particular CCCH frequency each time a BCCH, CBCH, or PCH channel is transmitted. In addition to the BCCH channel of its own cell, the terminal may also be prepared to select a new cell by receiving the BCCH channels of other cells in the vicinity. Naturally, the terminal may have a plurality of parts other than those shown in Figure 5, and the embodiment shown is not limiting to the invention: in practice, the same functions 30 may also be implemented in other ways.

In order for the terminal 500 to operate in accordance with the invention, the control block 508 must be programmed to recognize when the information received on the PCH channel represents a standard paging message and when the information received on the PCH channel would normally be received on the BCCH or CBCH. In addition, control block 508 needs to be programmed to determine certain criteria by which it can determine that data normally transmitted on the BCCH and / or CBCH has been sufficiently received on the PCH and thus does not require the receiver to be turned on s 106179 BCCH or CBCH. during channel reception. Such programming is per se known to one skilled in the art. For example, the cyclical nature of channel definition can be utilized in determining criteria. When looking at a particular period of time, after which the reciprocal ai-5 schedule of the BCCH, CBCH, and PCH channels is repeated, the control block 508 can check whether information on the BCCH and / or CBCH channel has been received on the PCH channel during the previous corresponding period. If so, there is no need to receive it during the current period from those channels whose information was received during the previous period on the PCH channel. During each period, upon receiving a PCH channel, control block 508 checks whether it contains information belonging to other channels.

An advantage of the invention is that the downtime required from the receiver of the terminal during idle mode is reduced by up to about 20% and consequently the terminal may remain correspondingly longer before its battery needs to be recharged. The operation according to the invention can be arranged by programming the base station 15 and the terminal to operate in a new way without necessarily interfering with their known component implementation, which is advantageous in manufacturing. In addition, terminals that do not support the operation of the invention are still fully usable, even if the base stations are programmed to operate in accordance with the invention: prior art terminals simply ignore messages on the PCH which they do not recognize as self-serving call messages. Similarly, a terminal according to the invention can also be used in a cell of a prior art base station, because when the terminal does not receive BCCH and CBCH data on the PCH, it receives it according to the prior art on its own channels.

The above describes the application of the invention mainly to the GSM system. It is understood, however, that the invention is not limited to any particular system, but is applicable to all cellular radio systems in which the paging channel is at least intermittently empty and information belonging to other channels is transmitted in parallel with the paging channel. Examples of other cellular radio systems include GSM 30 DCS 1800 and DCS 1900 (Digital Communications System at 1800/1900 MHz) extensions, PDC (Personal Digital Cellular), IS-54 and IS-96 (Interim Standard 54/96), and a proposed future third Universal Mobile Telecommunications System (UMTS) Generation Channel names in this patent application are exemplary only.

Claims (9)

1. Förfarande för överföring av data frän en basstation (100, 400) account en terminal (101, 500) inom et cellradiosystem, i flashing mellan basstationen och terminalen de-finerats en anropskanal (110) för överföring av nedätgäende begäran om uppkopp- Ling and allmän styrkanal (108, 109) för överföring av allmänna data beträffande en cell i basstationen, kännetecknat av att de allmänna data beträffande en cell i basstationen överförs pa anropskanalen (110) data anverskanalit (110) dataöver. än den sammanlagda informationsmängden i nedätgäende 30 begäran om uppkoppling som överförs. A method for transmitting information from a base station (100, 400) to a terminal (101, 500) in a cellular radio system, wherein a paging channel (110) is provided between the base station and the terminal for transmitting downlink requests and a generic control channel (108, 109). characterized in that general cellular information about the base station is transmitted on the paging channel (110) when the paging channel (110) has a communication capacity greater than the sum of the downlink connection requests to be transmitted. 2. Förfarande enligt patentkrav 1, kännetecknat av att allmänna data beträffande en cell i basstationen i stället för den allmänna styrkanalen (108, 109) Överförsää anropskanalen (110) d an anskskanalens dataöverföringskapacitet är stöne. "106179 A method according to claim 1, characterized in that generic base station cell information is transmitted instead of the general control channel (108, 109) on the paging channel (110) when the paging channel communication capacity is greater than the aggregate amount of downlink connection requests to be transmitted. 3. Förfarande enligt patentkrav 1, kännetecknat av att allmänna data beträffande en cell i basstationen förutom head allmänna styrkanalen (108, 109) Överförsää anropskanalen (110) da anropskanalens dataöverföringskapanet i den står. 5 A method according to claim 1, characterized in that generic base station cell information is transmitted in addition to the general control channel (108, 109) on the paging channel (110) when the paging channel communication capacity is greater than the aggregate amount of downlink connection requests to be transmitted. Förfarande enligt patentkrav 1, kännetecknat av att allmänna data beträffande en cell i basstationen överförs Pä anropskanalen i de delar (202) av nedätgäende begäran (200) om uppkoppling som annars blir tomma. 5. The patent for patent application No. 1, the coding of an att allmänna data beträffande en cell i basstationen överförs pä anropskanalen i andra meddelanden, som överförs förutom nedätgäende uppkopplingsbegäran som överförs pä anropskanalen. A method according to claim 1, characterized in that general information about the base station cell is transmitted in the otherwise empty parts (202) of downlink request requests (200) transmitted on the paging channel. * 5. A method according to claim 1, characterized in that general information about the base station cell is transmitted on the paging channel in other messages sent in addition to the downlink requests transmitted on the paging channel. Method according to claim 1, characterized in that - said cellular radio system is one of the following: GSM, DCS 1800, DCS 1900,. - said paging channel is one of the following: PCH, PAGCH and 30. said general control channel is one of the following: BCCH, CBCH. 6. Förfarande enligt patentkrav 1, kännetecknat av att 15. Such cellular radio system: GSM, DCS 1800, DCS 1900, - PCR, PAGCH och - this sub-station styrkanal är av avjande: BCCH, CBCH. 7. Basstation (400) inom et cellradiosystem, transmitting innefattar organ 20. för att hund (405, 408) nedätgäende begäran om uppkoppling hår an data channel, och för att här (403, 404, 408) allmänande data beträff en cell i basstationen allmänna styrkanalen, kännetecknad av att den innefattar organ (403, 404, 405, 408) för att allnän-25 na data beträffande en cell i basstationen main. A cellular radio system base station (400) comprising: means for transmitting downlink connection requests (405, 408) on a paging channel having a certain communication capacity and 10 106179 for transmitting (403, 404, 408) generic base station cell information on a known control channel. characterized in that it comprises means (403, 404, 405, 408) for transmitting general information about the base station cell on the paging channel. 8. Terminal (500) in the cellular radio system, transmitting the inefficiency organ (502, 503, 508) to the end of the uplink operation, and transmitting the data (302, 503, 508). , 504, 505, 509) allmänna data beträffande en cell pä •. basstationen head sub stänkanalen, kännetecknad av att den innefattar organ (502, 503, 508, 509) för att ta allmänna data beträffande en cell i basstationenää anropskanalen. A cellular radio system terminal (500) comprising: means for receiving (502, 503, 508) downlink set-up requests on a paging channel having a certain communication capacity, and - receiving general base station cell information (502, 503, 508, 504, 505); 509) on a general control channel, characterized in that it comprises means (502, 503, 508, 509) for receiving general information about the base station cell on the paging channel. The terminal according to claim 8, characterized in that it comprises a control block (508) and means for receiving information on the paging channel at predetermined intervals, wherein a) the control block (508) is monitored to determine whether, and (b) the control block (508) is temporarily tracked to prevent receiving data on the general control channel in response to the negative result from (a). 20 9. Terminal enligt patent krav 8, kennettecknad av att den innefattar et styrblock (508) och organ för retrieve data in anchoring channel inter-ler, colors 12 106179 a) styrblocket (508) inrättats att undersöka ifall en längre period än en given maximum period förflutit sedan allmänna data beträffande en cell i basstationen mottagits Pä anropskanalen föregäende Gang, och b) styrblocket (508) inrättats att temporärt forhindra mottagning av data pa den-5 result styrkanalen som £ pa negativt. «