KR20010033294A - Method and apparatus for transmission of messages within a communication system - Google Patents

Abstract

The short message transmission in the communication system 100 occurs as follows: The base station 101 in the communication system 100 determines that the short message transmission to the remote unit 113 needs to occur. The base station 101 then determines whether the paging channel circuit 107 is available. In particular, base station 101 determines whether paging channel circuitry 107 is loaded above a threshold. If the paging channel is loaded above the threshold and the remote unit 113 is not using the traffic channel, the base station 101 sends a short message to the remote unit 113 using the traffic channel. Also, no transmission to the remote unit 113 over the traffic channel is shown (ie, an individual using the remote unit 113 will not receive any indication that a traffic channel transmission is occurring).

Description

METHOD AND APPARATUS FOR TRANSMISSION OF MESSAGES WITHIN A COMMUNICATION SYSTEM}

Communication systems are already known and consist of many types, including terrestrial mobile radios, cellular radiotelephones, personal communication systems, and other types of communication systems. Within a communication system, transmission is done between a transmitting device and a receiving device via a communication resource, commonly referred to as a communication channel. In many types of communication systems, certain communication channels are used to transmit certain types of information to receiving devices. For example, in a communication system using a code division multiple access (CDMA) cellular communication system protocol, a traffic channel is used to transmit encoded voice and a paging channel is used to send shortened messages from a base station to a remote device within the communication system. Used to transmit. More specifically, the base station in the CDMA system will send a short message to all remote units communicating with the base station using up to seven paging channels (using communication Walsh codes 1-7). These shortened messages include, but are not limited to, call return numbers, predefined messages (eg, call home), or special services (eg, personalized traffic congestion reporting).

In operation, the base station needs to send many shortened messages to the remote unit in communication with the base station. Since only a limited number of paging channels are available, the paging channel capacity for sending all shortened messages in time may be insufficient. Accordingly, there is a need for a method and apparatus for transmitting messages in a communication system that increases the amount of messages that can be sent to a remote unit within the communication system.

FIELD OF THE INVENTION The present invention relates generally to cellular communication systems, and more particularly to data transmission within cellular communication systems.

1 is a block diagram of a base station for sending a message to a remote unit in accordance with a preferred embodiment of the present invention.

2 is a block diagram of the traffic channel circuit of FIG. 1 in accordance with a preferred embodiment of the present invention.

3 is a block diagram of the paging channel circuit of FIG. 1 for transmitting a shortened message, in accordance with a preferred embodiment of the present invention.

4 is a flow chart illustrating the steps used for data transmission from the base station of FIG. 1 in accordance with a preferred embodiment of the present invention.

FIG. 5 is a flowchart illustrating the steps used to create a traffic channel and send shortened messages by the traffic channel in accordance with a preferred embodiment of the present invention. FIG.

Generally speaking, the transmission of a short message in the communication system is as follows: The base station in the communication system determines whether a short message transmission to the remote unit needs to occur. The base station then determines whether the paging channel circuit is available. In particular, the base station determines whether the paging channel circuit is loaded above the threshold. If the paging channel is loaded above the threshold and the remote unit is not using the traffic channel, the base station sends a short message to the remote unit using the traffic channel. In addition, no transmission to the remote unit over the traffic channel is shown (ie, an individual using the remote unit will not receive any indication that a traffic channel transmission is taking place). The transmission of shortened messages over both paging and traffic channels results in an increase in the amount of messages that can be handled by the communication system. In particular, because shortened messages are sent to remote units using both traffic and paging channels, the capacity for sending shortened messages within a communication system is increased.

The present invention includes a message transmission method in a communication system in which a paging channel is mainly used for transmitting a shortened message and a traffic channel is mainly used for transmitting traffic channel data. The method includes determining if a traffic channel is currently being used by a remote unit and determining if the paging channel load is above a threshold. The message to the remote unit is then sent over the traffic channel based on the first and second determinations.

The present invention also provides a message in a multiple access communication system in which a paging channel uses a first group of spreading codes for transmitting shortened messages and a traffic channel uses a second group of spreading codes for transmitting traffic channel data. It covers the transmission method. The method includes a method of determining whether a traffic channel is currently being used by a remote unit and determining if the paging channel load is above a threshold. The message to the remote unit is then sent using the first spreading code selected from the spreading code of the second group if the traffic channel is not currently in use and the paging channel load is above the threshold, otherwise from the spreading code of the first group Send a message to the remote unit using the selected second spreading code.

Finally, the present invention relates to a message in a communication channel in which a paging channel uses a first group spreading code for transmitting shortened messages and a traffic channel uses a second group spreading code for transmitting traffic channel data. It includes a transmission device. The apparatus includes logic circuitry for determining if a traffic channel is currently being used by a remote unit and for determining if the paging channel load is above a threshold and if the paging channel load is above a threshold and if the paging channel load is above a threshold. Sending circuitry to the remote unit using the first spreading code selected from the spreading code, and otherwise sending the message to the remote unit using the second spreading code selected from the first group of spreading codes.

1 is a block diagram of a base station 101 for transmitting data to a remote unit 113 in accordance with a preferred embodiment of the present invention. In an embodiment of the present invention, the communication system 100 uses the CDMA system protocol, but in another embodiment the communication system 100 uses a narrowband enhanced mobile phone service (NAMPS) protocol, an improved mobile phone service (AMPS) protocol, mobile Analog or digital cellular communication systems, such as but not limited to, Global System for Communications (GSM) protocol, Personal Digital Cellular (PDC) protocol, or US Digital Cellular (USDC) protocol, are used. The communication system 100 includes a base station 101, a cellular message center 102, a remote unit 113, a central base station controller (CBSC) 103, and a mobile switching center (MSC) 104. In a preferred embodiment of the present invention, the base station 101 is preferably a Motorola SC9600 base station, the MSC 104 is preferably a Motorola EMX2500 MSC, and the message center 102 is a Motorola Message Register (MR) cellular message center (MCMC). ), And the CBSC 103 is preferably made of a Motorola CBSC device. As shown, the remote unit 113 is in communication with the base station 101 via an uplink communication signal 119 and the base station 101 is in communication with the remote unit 113 via a downlink communication signal 116. have. In a preferred embodiment of the present invention, base station 101 is suitably coupled to CBSC 103 and CBSC is suitably coupled to MSC 104. As shown, the base station 101 includes multiple traffic channel circuits 103, one or more paging channel circuits 105, a summer 111, and a modulator 115.

In a preferred embodiment of the present invention, communication of the short message to the remote unit 113 takes place using the paging channel circuit 107 and / or the traffic channel circuit 108. In a preferred embodiment, the paging channel circuit is referred to herein, "Mobile-Base Station Compatibility Standard for Dual-Mode Wideband Spread Spectrum Cellular Systems, Telecommunications Industry Association Interlime Standard 95A", Washington, DC, July 1993 (IS- 95A) in IS-95A sections 7.1.3.4, 7.6.2 and 7.7.2 and “Short Message Service for Broadband Spread Spectrum Cellular Systems”. In particular, the paging channel is used to send a short message to the remote unit 113 using the first group of spreading codes (eg, Walsh codes 1-7). In addition, the traffic channel circuitry is a circuit as described in IS-95A sections 7.1.3.5, 7.6.4, and 7.7.3, in which a second group of spreading codes (Walsh codes) are used to transmit traffic channel data to the remote unit 113. ).

The short message transmission from the base station 101 according to one embodiment of the present invention occurs as follows: The base station 101 determines that a short message transmission to the remote unit 113 needs to occur. In a preferred embodiment, the determination that a short message needs to be sent to the remote unit 113 is in response to a "next command request" sent by the remote unit 113, although other embodiments may use other determinations (e.g., Remote unit registration or termination of an ongoing call) may be used. The base station 101 then determines whether the paging channel circuit 107 is available. In particular, base station 101 determines whether paging channel circuitry 107 is loaded above a threshold. As described above, since the number of paging channels used for communication is limited, paging channel availability can be very limited. Unlike the conventional data transmission method, in the preferred embodiment of the present invention, if the paging channel is loaded above the threshold and the remote unit 113 is not using the traffic channel, the base station 101 uses the traffic channel to shorten the message. To the remote unit 113. In addition, in the preferred embodiment of the present invention, transmission to the remote unit 113 via the traffic channel is not shown (for example, an individual using the remote unit 113 does not receive any indication that a traffic channel transmission is occurring. Not). As mentioned above, the transmission of shortened messages over the paging and traffic channels results in an increase in the amount of messages that can be handled by the communication system 100. In particular, since the shortened message is transmitted to the remote unit using both the traffic channel and the paging channel, the capacity for transmitting the shortened message in the communication system is increased.

2 is a block diagram of the traffic channel circuit of FIG. 1 in accordance with a preferred embodiment of the present invention. The circuit 108 includes a channel multiplexer 216, a convolutional encoder 212, a symbol repeater 215, a block interleaver 216, a long code scrambler 217, and an orthogonal encoder 220. During operation, signal 210 is received by channel multiplexer 201 at a particular bit rate (eg, 8.6 kbit / second). In traffic channel circuit 108, signal 210 typically includes voice, pure data, or a combination of both types of data converted into data by a vocoder, but in a preferred embodiment of the present invention, signal 210 is It includes short message data, such as a single data packet containing a call return phone number. Channel multiplexer 201 multiplexes secondary traffic (eg, data) and / or signaling traffic (eg, control or user messages) on channel data 210 and 9.6 kbit / Output to convolutional encoder 212 in sec. The convolutional encoder 212 encodes the input data bits 210 into data symbols at a fixed encoding rate with an encoding algorithm (convolution or block coding algorithm) that facilitates the maximum possible decoding of the data symbols into data bits. For example, the convolutional encoder 212 may convert the input data bit 210 (received at a rate of 9.6 kbit / second) from one data bit to two data symbols (eg, rate 1/3). And the convolutional encoder 212 outputs the data symbol 214 at a rate of 28.8 ksymbol / second.

The data symbol 214 is then repeated by the iterator 215 and input to the interleaver 216. Interleaver 216 interleaves input data symbols 214 at the symbol rate. In interleaver 216, data symbols 214 are input into a matrix that defines data symbols 214 of blocks of a predetermined size individually. Data symbols 214 are input to locations within the matrix such that the matrix is filled in a column-by-column fashion. Data symbols 214 are individually output from locations within the matrix such that the matrix is emptied in a row-by-row manner. Typically, the matrix is a rectangular matrix with the same number of rows as the number of columns, but other matrix types may be selected to increase the output to interleave the distance between consecutively input non-interleaved data symbols. Interleaved data symbols 218 are output by interleaver 216 at the same data symbol rate (eg, 28.8 ksymbol / second) at which they are input. Data symbols of a predetermined block size defined by the matrix are derived from the maximum number of data symbols that can be transmitted at a predetermined symbol rate within a transmission block of a predetermined length. For example, if a transmission block of a predetermined length is 20 milliseconds, a data symbol block of a predetermined size is 28.8 ksymbol / second times 20 milliseconds, which is equivalent to 576 data symbols forming an 18x32 matrix.

The interleaved data symbol 218 is scrambled by the scrambler 217 and output to the quadrature encoder 220. Quadrature encoder 220 modulo 2 adds an orthogonal code (eg, 64-ary Walsh code) to each interleaved and scrambled data symbol 218. For example, in 64-ary orthogonal encoding, interleaved and scrambled data symbols 218 are each exclusively ORed by a 64 symbol orthogonal code. These 64 orthogonal codes preferably correspond to Walsh codes from a 64x64 Hamad matrix, where the Walsh codes are a single row or column of the matrix. Quadrature encoder 220 repeatedly outputs a Walsh code corresponding to input data symbol 218 at a fixed symbol rate (eg, 28.8 ksymbol / second).

The sequence of Walsh codes 242 is further spread by a pair of shortened pseudorandom codes 224 (eg, short compared to long codes) to produce I and Q channel code spreading sequences 226. I- and Q-channel code spreading sequences 226 are used to bi-phase modulate spherical sinusoidal pairs by driving power level control of the sinusoidal pairs. The sinusoidal output signal is summed, QPSK modulated (by modulator 115) and radiated by antenna 120 to complete transmission of channel data bits 210. In a preferred embodiment of the present invention, spreading sequence 226 is output at a rate of 3.6864 mega chips per second (Mcps) and radiated within a 5 MHz bandwidth, while in other embodiments of the present invention, spreading sequence 226 outputs at different rates. And can radiate within multiple bandwidths. For example, in another embodiment of the present invention, the IS-95A transmission mechanism is output at a rate of 1.2288 Mcps (traffic channel chip rate) within a 1.25 MHz bandwidth.

3 is a block diagram of the paging channel circuit 105 of FIG. 1 for sending a short message according to a preferred embodiment of the present invention. The paging channel circuit 105 includes a channel multiplexer 301, a convolutional encoder 312, a symbol repeater 315, a block interleaver 301, a block interleaver and a quadrature encoder 320. During operation, signal 310 (data) is received by channel multiplexer 301 at a particular bit rate (eg, 152.204 kbit / second). Channel multiplexer 301 multiplexes secondary traffic (eg, user data) on paging channel data 310 and outputs this multiplexed data to convolutional encoder 312 at 153.6 Kb / s.

Convolutional encoder 312 encodes input data bits 310 into data symbols at a fixed encoding rate with an encoding algorithm (e.g., a convolution or block coding algorithm) that facilitates maximum possible decoding of the data symbols into data bits. do. For example, the convolutional encoder 312 may convert the input data bit 310 (received at 153.6 kbit / second) from one data bit to two data symbols (eg, rate 1/3). By encoding at the convolutional encoder 312 outputs the data symbol 314 at a rate of 460.8 kbit / second.

The data symbol 314 is then input to the interleaver 316. The interleaver 316 interleaves the input data symbol 314 at the symbol level. In the interleaver 316, data symbols 314 are input into a matrix defining blocks of data symbols 314 of individually predetermined block sizes. Data symbols 314 are entered at locations within the matrix such that the matrix is filled in a column-by-column fashion. Data symbols 314 are individually output from locations in the matrix such that the matrix is emptied in a row-by-row manner. Typically, the matrix is a rectangular matrix with the number of rows equal to the number of columns; Another type of matrix may be selected to increase the output interleaving the distance between successive input non-interleaved data symbols. Interleaved data symbols 318 are output by interleaver 316 at the same data symbols (eg 460.8 ksymbol / second) they are input to. The data symbols of a predetermined block size formed by the matrix are derived from the maximum number of data symbols that can be transmitted at a predetermined symbol rate within a transmission block of a predetermined length. For example, if a transmission block of a predetermined length is 20 milliseconds, a block of data symbols of a predetermined size is 9.216 ksymbol.

Interleaved data symbols 318 are repeated by repeater 315 and output to quadrature encoder 320. Quadrature encoder 320 modulo 2 adds an orthogonal code (eg, a 16-ary Walsh code) to each interleaved and scrambled data symbol 318. For example, in 16-ary orthogonal encoding, the interleaved and scrambled data symbols 318 are each exclusive ORed by 16 symbol orthogonal codes. These 16 orthogonal codes preferably correspond to Walsh codes from a 16x16 matrix, where the Walsh codes are a single row or column of the matrix. Quadrature encoder 320 repeatedly outputs a Walsh code or inverse corresponding to input data symbol 318 at a fixed symbol rate (eg, 460.8 ksymbol / second).

The sequence of weighted Walsh codes 342 is also spread by a pair of shortened pseudo random codes 324 (ie, short as compared to long codes) to produce an I channel and Q channel code spreading sequence 326. I and Q channel code spreading sequences 326 are used to modulate a spherical sinusoidal pair by driving the power level control of that sinusoidal pair. This sinusoidal output signal is summed, QPSK modulated (by modulator 115) and radiated by antenna 120 to complete the transmission of channel data bits 310.

4 is a flow chart illustrating the transmission of a short message from the base station 101 in accordance with a preferred embodiment of the present invention. The logic flow begins at step 401 where the MCMC 102 determines that a short message needs to be sent to the remote unit 113. As described above, the determination of whether a shortened message needs to be sent to the remote unit 113 responds to a new shortened message left for the remote unit, or a request by the remote unit for the next message, or the end of the phone call. It is. In another embodiment of the present invention, the short message system is used to utilize idle forward channel data capacity to send a short message during a phone call to facilitate delivery. In step 405 the MCMC 102 determines whether the remote unit 113 is currently using a traffic channel, and if not, the logic flow proceeds to step 410 and if so, the logic flow continues to step 415. At step 410, MCMC 102 determines whether paging channel usage is above a threshold. In particular, the MCMC determines if current paging channel usage is at least 75%. If it is determined in step 410 that the paging channel usage is not above the threshold, the logic flow continues to step 415, otherwise to step 420. In step 415 the base station 101 sends a short message to the remote unit 113 (via the downlink communication signal 116) and the logic flow continues to step 430. In particular, as described in IS-95A section 7.7.5 and IS-637 section 4.3, the short message is sent by the base station 101 to the idle remote unit 113 to send an “Alert with info” message to the remote unit 113. Warning messages). The remote unit 113 indicates receipt of the short message in response to the "authentication" message. In a preferred embodiment, the non-idle remote unit 113 (during the call) receives a “data burst message” message on the forward traffic channel including the shortened message (IS-637 2.4.2.1.2.4). In step 420, the base station 101 establishes a traffic channel with the remote unit 113 and sends a short message (via a call not shown) to the remote unit 113 via the traffic channel. Next, at step 425, the remote unit 113 buffers the message, and at step 430 the logic flow ends.

FIG. 5 is a flowchart illustrating the steps required to create a traffic channel and send a short message over the traffic channel in accordance with a preferred embodiment of the present invention (step 420 of FIG. 4). The logic flow is that the remote unit 113 is not actively communicating to the base station 100 using the traffic channel, but actively controls the forward control channel (IS-95A paging channel) to inform the transmission in progress by the base station 100. Beginning at step 501 being monitored. As described above, the paging channel circuitry is used to send messages to the remote unit 113 to indicate ongoing downlink transmissions. In step 505 the base station 100 notifies the remote unit 113 of the ongoing data transfer (via the paging channel) and assigns the remote unit 113 as a first channel (traffic channel). In a preferred embodiment of the present invention, traffic channel assignment occurs as described in IS-95A section 7.6.2 except that the remote unit 113 is instructed to set up a call, such as a call that is not shown. As described above, this is accomplished by sending a warning message with the "no tone" ringer selection type to the remote unit 113. The remote unit 113 acknowledges the warning and accesses this assigned channel. Upon arrival at the channel, the remote unit 113 receives a “data burst” message (IS-95A section 7.7.3.3.2.4) including a short message, waits a reasonable time for receipt authentication of the message, and the base station 101 Emits a traffic channel (IS-95A 2.4.2.1.2.3). Once the traffic channel is assigned to the remote unit 113, the logic flow continues to step 510 to indicate the amount of free buffer space used by the remote unit 113 to send an authentication sequence to the base station 101 and to store the short message. Next, step 515 is followed. In step 515 the base station 101 determines whether the buffer space is available in the remote unit 113 and if not available the logic flow proceeds to step 535 where the traffic channel is stopped and if available the step flows to step 520 and the base station 101 Begin sending a short message to the remote unit 113 over the traffic channel. In a preferred embodiment of the present invention, the base station 101 transmits sufficient information to the remote unit 113 to fill a single buffer in step 520, and the logic flow continues to step 525. In step 525 the MCMC 102 determines whether the buffer space is still available in the remote unit 113, if not available the logic flow continues to step 535 where the buffer channel is stopped, and if available the logic flow is step 530 In which MCMC 102 determines whether further short messages need to be sent to remote unit 113. In step 530 the MCMC 102 determines if there is another short message sent to the remote unit 113, then the logic flow returns to step 520, otherwise the logic flow proceeds to step 535 where the traffic channel is It stops.

While the present invention has been shown and described with reference to specific embodiments, it will be understood by those skilled in the art that various forms of modifications may be made without departing from the spirit and scope of the invention, and such modifications are within the scope of the following claims.

Claims (12)

A method of transmitting a message in a communication system in which a paging channel is used to transmit shortened messages and a traffic channel is used to transmit traffic channel data. Determining whether a traffic channel is currently being used by a remote unit to make a first determination; Determining if the paging channel load is above a threshold to make a second determination; And Sending a message to the remote unit over the traffic channel based on the first and second determinations Message transmission method comprising a. 2. The method of claim 1, wherein sending a message to the remote unit includes sending a shortcut message to the remote unit, wherein the shortcut message is a call return number, a predetermined message, a special service message, and an individual traffic congestion. A method for sending a message that is selected from a group of reports. The method of claim 1, wherein sending a message to the remote unit comprises: sending a shortened message to the remote unit over the traffic channel if the traffic channel is not currently in use and the paging channel load is above the threshold; Otherwise sending the message to the remote unit via a paging channel. 2. The method of claim 1, wherein sending a message to the remote unit comprises sending the message to the remote unit via the traffic channel, wherein the individual using the remote unit is responsible for generating the traffic channel transmission. A message transmission method that does not receive any indication that it is present. A message transmission method in a multiple access communication system in which a paging channel transmits a shortened message using a spreading code of a first group and a traffic channel transmits traffic channel data using a spreading code of a second group. Determining whether a traffic channel is currently being used by a remote unit; Determining if the paging channel load is above a threshold; And If the traffic channel is not currently in use and the paging channel load is above the threshold, send a message to the remote unit using a first spreading code selected from the spreading code of the second group; Sending the message to the remote unit using a second spreading code selected from a spreading code Message transmission method comprising a. 6. The method of claim 5, wherein sending a message to the remote unit includes sending a shortcut message to the remote unit, wherein the shortcut message includes a call return number, a predetermined message, a special service message, and individual traffic. A method of sending a message selected from a group of overcrowded reports. 6. The method of claim 5, wherein sending a message to the remote unit comprises sending the message to the remote unit via the traffic channel, wherein the individual using the remote unit is responsible for generating the traffic channel transmission. A message transmission method that does not receive any indication that it is present. A message transmission apparatus in a communication system in which a paging channel transmits a shortened message using a spreading code of a first group and a traffic channel transmits traffic channel data using a spreading code of a second group. Logic circuitry to determine if a traffic channel is currently being used by a remote unit and to determine if the paging channel load is above a threshold; And If the traffic channel is not currently in use and the paging channel load is above the threshold, send a message to the remote unit using a first spreading code selected from the spreading code of the second group and otherwise spread the first group Transmitting circuit for transmitting the message to the remote unit using a second spreading code selected from the code Message transmission device comprising a. 9. The apparatus of claim 8, wherein said communication system is a code division multiple access (CDMA) communication system. 9. The apparatus of claim 8, wherein said transmitting circuit is a circuit selected from the group consisting of a paging channel circuit and a traffic channel circuit. The apparatus of claim 8, wherein the message is a short message. 12. The apparatus of claim 11, wherein the shortened message is a message selected from the group consisting of a call return number, a predetermined message, a special service message, and an individual traffic congestion report.