KR100212482B1 - Broadcast message transmitting method in cdma short message service - Google Patents

Abstract

In the case of a broadcast message to be transmitted through a paging channel, the present invention can not sufficiently transmit information because the 2-byte complete Hangul can not be transmitted by only 27 characters at maximum. The present invention provides a data burst message And transmits the data burst message over a continuous slot to extend the effective size. In order to realize this, a 1-bit mored message field is added to the data burst message to notify the mobile station that the size of the message exceeds one slot, A method for transmitting a broadcast message in a code division multiple access (CDMA) short message service in which a carrier can transmit a lot of information to a broadcast service subscriber in detail by increasing a maximum limit.

Description

Method of transmitting broadcast message in code division multiple access (CDMA) short message service

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a Short Message Service (CDMA) system of a Code Division Multiple Access (CDMA) cellular system, and more particularly to a method of transmitting a broadcast message in a short message service of a CDMA cellular system .

In a CDMA cellular system, 'Short Message Service' is a simple message exchanging numbers and characters between mobile stations using control channels such as paging channels and access channels as well as communication channels. At present, the standard for short-haul services is not established in Korea, but in the United States, the provisional standard EIA / TIA IS-637 is documented. In the telecommunication service layer, which is one of the short message service protocols, five messages are defined, and these messages are filled in a data burst message (hereinafter referred to as " CHARi ") field defined in IS- It is exchanged with the message center. The type of tel

CDMA cellular messaging teleservice < RTI ID = 0.0 >

CDMA Digital Paging Teleservice

CDMA Voice Mail Alert / Notification Teleservice

CDMA Cellular Broadcast Teleservice < RTI ID = 0.0 >

.

The CDMA Cellular Broadcast Teleservice (CDMA Cellular Broadcast Teleservice) related to the present invention is a service for delivering information such as weather and major news to all mobile stations in a corresponding area where a service provider is set to receive a broadcast service. The base station sets the address field of the data burst message including the broadcast information to a broadcast address instead of a specific mobile station address and transmits the broadcast address through the paging channel so that all the mobile stations to which the broadcast telemory service is permitted receive the broadcast address. Since the recipient of this message will be almost all mobile stations in the domain and therefore the load of the system is too great to receive the reception response of each mobile station, the base station does not require the mobile station to respond to the message reception. Since the mobile station in the call at the moment of transmission of the broadcast message does not monitor the paging channel, it is specified in IS-637 to deliver the message over the assigned current call channel.

Meanwhile, the portable mobile station can operate in a slot mode to reduce power consumption. The mobile station operating in the slot mode monitors only one or two slots that are in agreement with the base station and stops the operation of the receiver in the remaining slots to conserve power. According to the requirements of IS-95A, all messages of the paging channel must be transmitted within one to two slots of the paging channel, and the size of the message body is determined according to the data rate of the paging channel. Slotted page messages can be transmitted up to 2 slots depending on whether the MORE_PAGES field is set or not. However, all the paging channel messages except for the MORE_PAGES field are transmitted in 1 slot for 80 msec . Therefore, a data burst message related to a short message service must transmit a short message within one slot, and a data burst message including the broadcast message is sent to all mobile stations at a predetermined slot time for broadcasting teleservice.

The transmission rate of the paging channel is 4800 bps or 9600 bps. The maximum size of the message body of the paging channel is 722 bits when the system is servicing the paging channel data rate at 9600 bps. As shown in Table 1, the size of the data burst message excluding the CHARi field is the address length (ADDR_LEN) 4 is 90 bits.

So the maximum size a CHARi field can have is

722 - 90 = 632 bits = 79 bytes

And the minimum overhead of a short message is 25 bytes, the effective broadcast information that can be actually transmitted is about 54 bytes. That is, if the present CDMA short message service system which complies with the requirements of IS-95A and IS-637 performs a broadcast telephony service using a 2-byte complete Hangul, only a maximum of 27 characters can be transmitted. The 27 characters here are far less than the 255 characters specified in the CDG, and are insufficient to convey sufficient information. In the case of a non-broadcast telecommunication service, the base station can open and service the forward communication channel for further information transmission. However, the broadcasting teleservice can not use the paging channel since all the mobile stations are the reception targets being).

In the case of broadcast messages to be transmitted through the paging channel, the maximum number of valid broadcast information that can be transmitted in the existing system is limited to 27 characters for actual service.

Accordingly, the present invention increases the maximum effective size of a broadcast message in a CDMA short message service by reducing restrictions on the number of characters in actual service by increasing the maximum value of effective broadcast information, have.

In order to achieve the above object, the present invention provides a CDMA mobile station operating in a slotted mode, in which a data burst message having a size limited to one slot is transmitted over two consecutive slots when broadcasting a broadcast service, A MORE_MSGS field is added to the data burst message of the mobile station to inform the mobile station that the size of the message exceeds one slot so that the mobile station receiving the broadcast message checks the MORE_MSGS field If the value is '0', only one corresponding slot is checked. If the value is '1', a relatively long broadcast message can be received by extending the reception to the next slot.

FIG. 1 is a flowchart illustrating a broadcast message transmission procedure of a CDMA base station according to the present invention;

In order to realize the present invention, a one-bit MORE_MSGS field is added to an existing data burst message as shown in Table 2 to inform the mobile station that the size of the message exceeds one slot.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

1 is a flowchart illustrating a broadcast message transmission procedure of a CDMA base station according to the present invention. (1) whether the length of a broadcast message to be transmitted when a broadcast message transmission request is received can be filled in one slot of a paging channel; (2) If the message transmission request is not received, it waits until it is received. If it is determined in step (2) that the message can be filled in one slot, the MORE_MSGS field value is set to 0, (3) the scheduled broadcast message transmission time is awaited, (4) The data burst message is transmitted through the paging channel in one slot (5). If it is determined in step (2) that the message can not be filled in one slot, it is determined whether the message can be filled in two slots (6). If it is determined in step 6 that the message can be filled in 2 slots, the MORE_MSGS field value of the data burst message is set to 1 (7), and then it is determined whether it is the promised broadcast transmission time (8) . When the scheduled broadcast message transmission time arrives, the data burst message is transmitted through the paging channel in two consecutive slots and transmitted (9). If it is determined in step 6 that the message can not be filled in 2 slots, the transmission of the message is canceled after error processing 10 and the process goes to the idle state.

The maximum size of the message body of the paging channel is 1482 bits, and the size of the data burst message excluding the CHARi field is set to the address length (ADDR_LEN) is 4, it is 90 bits. Therefore, when the maximum size that the CHARi field can have is 1482 - 90 = 1392 bits = 174 bytes, and the minimum overhead of the short message is 25 bytes, the effective broadcast information available for actual transmission is about 149 bytes. In 2-byte complete Hangul, it can be up to 74 characters, so it can send 47 characters more than the existing 27 characters, so it increases by about 174%.

Also, the present invention applies equally to a case where the transmission rate of the paging channel is 4800 bps. In the case of 1 slot transmission, the maximum size of the CHARi field is 31 bytes under the condition of 9600 bps, and if the minimum overhead 25 bytes of the short message is subtracted, it is 6 bytes, that is, 2 bytes. In the proposed 2-slot transmission method, the maximum size of the CHARi field is 75 bytes, and if the minimum overhead 25 bytes of the short message is subtracted, the number of bytes can be increased to 50 bytes.

As described above, according to the present invention, in the broadcast telephony service of the CDMA short message service, the limit of 27 characters of the 2-byte complete Hangul character, which is the maximum effective broadcast information of the existing system, is increased to 74 Korean characters, So that the service provider has a great effect that the broadcast service subscribers can transmit more information in detail than the conventional method.

Claims (1)

Determining whether a broadcast message transmission request is received from a message center at a base station; and determining whether a broadcast message transmission request is received from the message center according to whether the broadcast message transmission request is received. The method comprising the steps of: determining whether the broadcast message transmission request is received, waiting until the broadcast message transmission request is received if the broadcast message transmission request is not received; Setting a value of a mower message field of the data burst message to 0 if it is determined that the message can be filled in one slot according to a determination result; Determining whether the broadcast message transmission time Transmitting a data burst message in a slot through a paging channel when the transmission time reaches a predetermined transmission time according to a result of the determination; Determining whether a message can be filled in two slots if it is determined that the message can not be filled in one slot according to a determination result that the length of the broadcast message can be filled in one slot; Setting a value of a mower message field of the data burst message to 1 if it is determined that the message can be filled in 2 slots according to a result of determining whether the length of the broadcast message can be filled in 2 slots, Determining whether the broadcast message transmission time is an appointed time after setting the value to 1; The method comprising the steps of: filling a data burst message in a consecutive two slots through a paging channel and transmitting the promised broadcast message transmission time according to a determination result of whether the broadcast message transmission time is an embedded broadcast message transmission time; If it is determined that the message can not be filled in two slots according to a result of the determination whether the length of the broadcast message can be filled in two slots, And canceling transmission of the message after the error processing and proceeding to the idle state.