GB2340348A

GB2340348A - Data transmission in a mobile telephone system

Info

Publication number: GB2340348A
Application number: GB9924514A
Authority: GB
Inventors: Keijiro Take; Akira Otsuka
Original assignee: Mitsubishi Electric Corp
Current assignee: Mitsubishi Electric Corp
Priority date: 1995-04-18
Filing date: 1996-04-17
Publication date: 2000-02-16
Anticipated expiration: 2016-04-17
Also published as: GB2340348B; GB9924516D0; GB2340349A; GB9924514D0; GB2340349B

Description

2340348 RADIO DATA TRANSMISSION SYSTEM This invention relates to a packet

data transmission system in radio communication systems centering on telephones such as a digital cellular system and a digital cordle-ss telephone system.

In a conventional radio communication system consisting of a plurality of base stations, a switching system, and a plurality of mobile stations existing in a radio zone formed by the base stations, to transmit and receive telephone and d6ta signals between the base and mobile stations, a TCH is assigred between the mobile and base stations using a CCH, then the TCH is used to execute one-to-one two-way data communication between the mobile and base stations.

For example, as described in Japanese Patent Unexamined No. Hei 6r77886, when receiving a data communication request from a mobile station, the base station and switching system select one or a plurality of TCHs in accordance with the channel use state and if the requested TCH can be selected, assigns the TCH to the mobile station, which then executes data communication on the assigned TCH.

on the other hand,, to transmit and receive data between a plurality of mobile stations and a base station, in the radio communication system a common channel is provided for accommodating a plurality of mobile stations and data is transmitted and received by making random access in the common channel in addition to the above- mentioned method of assigning a TCH between mobile and base stations by the line switching for _providing a one-to-one two-way data co=unication lineThe random access method is used for a CCH in the line switching.

For example, as described in Japanese Patent Unexamined No. Hei 5-95358, in channel contention control in the random access system, an up link signal from a mobile station to a base station and a down link signal are put into slots on a common channel, the slots of the up and down link signals are synchronized with each other, and transmission disable/enable information for controlling mobile station transmission is suffixed to each of the slots making up the down lik signal.

In each base station, the up link channel is monitored in each slot and in the slot detecting an up link signal from a mobile station, the transmission disable/enable information suffixed to the slot of down link signal is changed to transmission disable for disabling other mobile stations from originating calls in the next slot for avoiding signal collision.

When receiving the transmission disable/enable information indicating transmission disable from the base station, the mobile station where up link information to the base station occurs continues to monitor the transmission disable/enable information until the information is changed to transmission enable. When the information is changed to transmission enable, the mobile station judges transmission start or standby in the next slot according to the transmission -proba-bl- 11-ty.

In the above-mentioned data communication by the line switching, one mobile station occupies one TC9 and high-speed data communication can be conducted, but a connection delay occurs because of the TCH assignment process. In the data communication by the random access system, the"connection delay is small, but if a plurality of mobile stations access one TCH, high traffic is handled and the throughput lowers. To use a plurality of TCHsj management among the TCHs is required.

In the invention, radio physical channels for transmitting and receiving user information are called communication channels (TCHs) and those for transmitting and receiving control information used for radio channel establishment and call connection are called control channels zo (CCHs). However, to use all or some of TCHs to transmit and receive the control information, all or some of the TCHs are logically called TCH attendant control channels (ACHs). Further, when a TCH is used to transmit and receive a telephone signal, it is logically called a voice channel (VCH) and when Z5 a TCH is used for data communication using random access, it is called a random access channel (RACH).

I . -1 That is, the VCH and RACH represent different channeals in function, but are TCHs as radio physical channels.

According to a first aspect of the invention, there is provided a radio data transmission system comprising a plurality of base stations, a plurality of mobile stations, and 10 a base station controller and.having a channel configuration wherein radio channels between each base station and a plurality of mobile stations consist of a CCH and a plurality of TCHs wherein each of the base stations uses a plurality of 15 TCHs as RACHs when a time division multiple access (TDMA) system is used as a radio access system, characterized in that each of the mobile stations compri ses means for generating a segment with a synchronization bit and the mobile station number of the mobile station and sending the segment to an RACH aquired - by the no-bl-le statIon.. t-hat eacb o-f the -base stations comprises means, upon normal reception of the segment., for notifying the mobile station of the use right o the RACH on the down channel of the RACH and providing information indicating that other mobile stations acquiring the RACH are disabled from transmitting a packet, and means for establishing up synchronization by using the segment,, that each of the mobile stations 'comprises means for adding numbers for identifying the segments, and that the base station controller is or each of the base stations comprises means for releasing the use right upon reception of the last segment according to the segment identification numbers.

According to a second aspect of the invention, there is provided a radio data transmission system comprising a plurality of base stations, a plurality of mobile stations, and a base station controller and having a channel configuration wherein radio channels between each base station and a plurality of mobile stations consist of a CCH and a plurality of TCHs wherein each of the base stations uses a plurality of TCHs as RACHsr characterized in that the base station controller comprises a conversion table for representing - 5.- correspondence among mobile station numbers identifying the mobile stations, addresses identifying the mobile stations in a LAN, and channel numbers CNs; identifying RACHs, means for searching the conversion table and changing data described in the table upon reception of an RACH use request f rom. one of the mobne stations or a new segment, and means for rewriting the conversion table if data does not exist.

According to a third aspect of the invention, there is provided a radio data transmission system comprising a plurality of base stations.. a plurality of mobile stations, and a base station controller and having a channel configuration wherein radio channels between each base station and a plurality of mobile stations consist of a CCH and a plurality of TCHs wherein each of the base stations use a plurality of TCHs as RACHs, characterized in that the base station controller comprises means, upon reception of a packet from a LAN, for searching a conversion table for the PLACH number of the RACH acquired by the mobile station for which the packet is destined and sending a packet incoming notification to the base station managing the RACH, that the base station- comprises means for passing on the packet incoming notification on all RACHs managed by the base station when receiving the packet incoming notification, that the mobile station comprises means.. if the mobile station is shifting from one RACH to another, for stopping the channel shifting and returning to the channel shifting start RACH upon reception of the call incoming 7notification, and that the base station controller comprises means for transmitting the packet on the RACH corresponding to the mobile station number of the mobile station stored in the conversion table after sending the packet incoming notification.

Thus in the first aspect of the invention in the radio packet data communication system, when a mobile station waiting for sending a packet recognizes that an up link is unassigned according to the channel information from the base station or the base station controller on the down link of the RACH acquired by the mobile station, it sends the first segment containing a synchronization bit on the up link of the RACK If the segment is normally received and up synchronization is set, the mobile station can acquire the RACH and then sends segments consecutively on the RACH. The base station controller assembles the segments sent from the mobile station into a packet and sends the packet to the LAN.

Since the segment containing a synchronization bit is used for contention control, each mobile station need not establish up synchronization at the RACH assignment time or the shift time. Since each mobile station can acquire the RACH use right in units of packets that can be sent to the LAN, this aspect of the invention has the effect of enabling the base station controller to assemble segments sent from a mobile station into a packet that can be sent to the LAN.

With the second aspect of the invention, in the system the base station controller uses a conversion table to manage the correspondence among the terminal identifiers of the mobile stations acquiring RACHs, the identifiers of the RACHs, and the identifiers of the mobile stations on the LAN, and changes the conversion table according to the route of the packet received when each mobile station makes an RACH use request or makes a channel shift. Thus, since the base station controller converts and manages terminal identifiers used with the LAN and those used with the radio communication system, processing can be performed on the LAN without being concerned with a move of mobile stations. Since RACHs acquired by mobile stations are managed with the channel numbers CN of TCHs, an incoming packet can be transmitted on the TCH having the corresponding CN. - With the third aspect of the invention, in the radio packet data communication system, the base station controller searches the conversion table based on the destination of a packet received from the LAN or a mobile station. If a mobile station corresponding to the destination exists, the base station controller sends a packet reception notification to all RACHs controlled by the base station managing the R-ACH acquired by the mobile station, then transfers the packet to the RACH corresponding to the mobile station stored in the conversion table. If the mobile station receives the packet reception notification while shifting from one channel to anther, it returns to the shift source RACH and receives the transferTed packet. Thus, since move management is executed without position registration from mobile stations, this aspect of the invention has the effect of reducing position registration traffic and facilitating transmission of an incoming packet to the mobile station for which the packet is destined.

The invention will be further described by way of non-limitative example with reference to the accompanying drawings, in which:

Figure I is a flowchart of TCH assignment in a conventional example-, Figure 2 is a schematic diagram of RACH contention control in a conventional example-, Figure 3 is a schematic drawing of a radio communication system.

Figure 4 is a carrier configuration diagram to use a TDMA system fro a radio line between base and mobile stations; Figure 5 is an illustration showing one embodiment of a segment construction method in a mobile station; Figure 6 is a sequence chart showing one embodiment of a line contention method; Figure 7 is a block diagram showing one embodiment of the configuration of the base station controller and is a table showing one example of entries of a conversion table registered in the base station controller, Figure 8 is a flowchart showing one embodiment of a conversion table management method in the base station controller.

Figure 9 is a flowchart showing one embodiment of a packet incoming process in the base station controller-, Figure 10 is a flowchart showing one embodiment of a packet incoming process in a mobile station; and Figure I I is a sequence chart between mobile stations and the base station controller showing one embodiment of a packet incoming system.

Figure 3 is an illustration showing a radio communication system for executing communication between base stations and mobile stations. Figure 4 is a diagram showing the carrier configuration to use a TDMA (time division multiple access) system for a radio line between base and mobile stations.

A base station controller is connected to base stations, each of which forms a radio zone for providing TCHs for mobile stations. The base stations and the base station controller always control TCHs unused for telephone call as RACM.

Embodiment 1:

Figure 5 is an illustration showing one embodiment of a segment construction method in a mobile station in the invention. Figure 6 is a sequence chart showing one embodiment of a line contention method in the invention.

Figure 5 shows an example in which a packet containing IP header 090 1, TCP header 0902, and user data 0903 sent to a LAN is divided in a size that can be sent by TDMA in a radio zone. Each division to which an identification code 0906 for identifying the division order, etc., is added is called a segment. A synchronization bit 0904 for synchronizing up link of RACH and a mobile station number 0905 for identifying a mobile station also make up a segment which 0907 is created in the mobile station at the packet transmission time. The segment 0907 made up of the synchronization bits and the mobile station number is first transmitted before packet transmission and therefore is called the first segment which is followed by the second segment 0908,..., last segment 0909 in the transmission order.

Next, the packet transmission operation will be discussed. Assume that mobile station #2 uses one RACH to transmit a packet in Figure 6. First, the mobile station #2 transmits the first segment containing the syndh-ronizat7von-bits and the mobile station number for identifying the mobile station 7#2 to a base station at 0911.

The base station, which normally receives the first segment, synchronizes up RACH between the mobile station and the base station, and determines that the use right of the RACH is granted to the mobile station 7#2. Then, the base station uses the down link of RACH attendant control channel corresponding to the RACH to notify, with use right setting at is 0912, the mobile station #2 that the mobile station 7#12 is granted the use right of the RACH and the mobile stations acquiring the RACH other than the mobile station #2 (mobile stations #1 and #3) that the mobile stations 41 and #3 are disabled f rom transmitting a packet, and transmits the first packet to the base station controller at 0913.

The mobile station #2 recognizes that the use right of the RACH is granted, and transmits the second and later segments in which the packet information is set to the base station, which then transmits the received segments to the base station controller. When the base station receives the last segment from the mobile station #2 at 0918, it notifies the mobile stations that the right use of the RACH granted to the mobile station #2 is released with use right release at 0920. The mobile stations acquiring the RACH other than the mobile station #2 cannot transmit segments between reception of the use right setting at 0912 and reception of the use right r-lease at MID.

e According to the method, since the segment containing the synchronization bits is used for contention control, the mobile station need not take up synchronization at the RACH assignment time and at the shift time. Since each mobile station can acquire the RACH use right in units of packets that can be sent onto the LAN, the base station controller can assemble segments consecutively sent from the mobile station in the reception order for reconstructing a packet that can be sent to the LAN, simplifying the packet reconstruction process. Embodiment 2:

Figure 7 is a block diagram showing one embodiment of the configuration of the base station controller in the invention and also provides a table (Table 2) showing one embodiment of entries of a conversion table registered in the base station controller in the invention. Figure 8 is a flowchart showing one embodiment of a conversion table management method in the base station controller in the invention.

Move management of mobile stations for transmitting and receiving a packet between the mobile stations and a LAN will be discussed. As shown in Figure 7, the base station controller 1001 has a LAN interface function 1008 for connecting to the LAN,, a packet reception/transmi s s ion function 1007 for receiving a packet from the LAN and transmitting a packet to the LANr a base station interface function 1005 for connecting to base stations, a segment reception/transmission function 1004 for receiving segments via base stations from mobile stations and transmitting segments via base stations to mobile stations, a packet assembly/segmentation function 1003 for assembling segments destined for the LAN from a mobile station into a packet and dividing a packet destined for a mobile station from the LAN into segments, and the conversion table 1002 for holding information for managing a move of the mobile stations. For example, as listed in Table 2, the conversion table 1002 sets mobile station numbers TNs 1011 for uniquely identifying the mobile stations, addresses TAs 1012 for identifying the mobile stations in the LAN, and RACH channel numbers CNs 1013 indicating RACHs acquired by the mobile stations.

Updating the conversion table 1002 will be discussed with ref erence to Figure 8. The conversion table 1002 is updated upon reception of an RACH use request from a mobile station or a packet transmitted from a mobile station to the LAN. When receiving an RACH use request from a mobile station at step S1002, the base station controller 1001 searches the 12 conversion table 1002 for information concerning the mobile station transmitting the use request at step S1003.

For example, if the mobile station TN2 transmits an RACH CN3 use request, the base station controller 1001 determines whether or not the mobile station TN2 is registered im the conversion table TOM at step SIDD4. -in -tWls case, since the mobile station TN2 is registered in the conversion table 1002 as listed in Table 2 (Yes at step S1604), the base station controller 1001 check's to see if the entry of the CN 1013 in the conversion table corresponding to the mobile station TN2 is CN3 at step S1005. Since the CN corresponding to the TN2 is CN2 in Table 2, the base station controller 1001 changes the CN in the conversion table to CN3 at step S1007.

If an RACH use request is received from a mobile station not registered in the conversion table, the TN and TA of the mobile station and the CN requested by the mobile station are set in the conversion table at step S1006.

Next, when receiving a packet destined for the LAN over the RACH channel CN2 from the mobile station TNI at step S1008, the base station controller 1001 compares the CN used to transmit the packet with the CN corresponding to the mobile station TNl in the conversion table at step S1009. In the example listed in Table 2, since the CNS do not match as a result of the comparison, the CN in the conversion table is changed to CN2 at step S1007. The conversion table for position management of the mobile stations is thus updated.

13 - According to the method, the base station controller converts and manages the terminal identifiers used in the LAN and those used in the radio communication system, thus processing can be performed in the LAN without being concerned with a move of the mobile stations and the base station cont-rol-Ie-r need-s only to assemble segments consecutively sent from a mobile station in the sequence number into a packet that can be sent to the LAN, simplifying the packet reconstruction process.

Embodiment 3:

Figure 9 is a flowchart showing one embodiment of a packet incoming process to a mobile station which autonomously shifts from one RACH to another,, in the base station controller in the invention. Figure 10 is a flowchart showing one embodiment of a packet incoming process in a mobile station which autonomously shifts from one RACH to another in the invention. Figure II is a sequence chart between mobile stations and the base station controller showing one embodiment of a packet incoming system in the invention.

A process performed when the base station controller receives a packet destined for a mobile station from the LAN will be discussed. When the base station controller receives a packet from the LAN at step S1101 in Figure 9, it searches the conversion table (1002 in Figure 7) contained in the base station controller for information concerning the mobile station for which the packet is destined and finds the mobile station number TN of the mobile station and the RACH channel number CN acquired by the mobile station at step S1102. The base station controller transmits a packet incoming notif ication via the base station managing the found CN to the mobile station for which the packet is destined at step S1103.

Eere, 'the packet incoming notIfIcation is sent to "the 'base station at 1102 in Figure 11, which then passes on the received notification for each RACH over the down attendant control channels of all managed RACHs at 1103-1105. For example, assume that the mobile station TN2 is the packet destination and is shifting from RACH channel CN2 to CN1. After receiving the packing incoming notification on CNI at step S1111 in Figure 10, the mobile station TN2 is shifting from CN2 to CNI (Yes at step S1112) and therefore stops the channel shifting at step S1113 and returns to CN2 of the channel shifting start RACH at step S1114.

After transmitting the packet incoming notification to the base station, to wait for the packet incoming notification transmission process from the base station to the mobile stations, the channel shifting stop process of the mobile station, and the return process of the mobile station to the channel shifting start RACH, the base station controller starts a timer at 1106 and walits for the timer to time out at 1107, thereby executing a delay process for transmitting the packet 2-5 at step S1104. After the delay process, the base station controller transmits the packet to the mobile station TN2 at step S1105. To transmit the packetr the base station controller divides the packet into segments, specifies the RACH channel number CN2 f or the base station,, and transmits the segments to the base station at 1108- 1110. The base station passes on the received segments to the mobile station over CN2 at 7171-11 --1'1-1'3.

According to the method, since move management is executed without explicitly registering positions from mobile stations, the traffic for registering the positions is decreased. Also, since the RACHs acquired by the mobile stations are managed with the TCH channel numbers CNs, an incoming packet can also be transmitted on the TCH having the corresponding CN to a mobile station which autonomously shifts from one RACH to another, thereby enabling a packet incoming call.

Claims

A radio data transmission system, comprising:

a plurality of base stations; plurality of mobile stations; and base station controller, in which radio channels between each base station and a plurality of mobile stations consist of a control channel (CCH) and a plurality of communication channels (TCHs) and down channels of the TCHs include an attendant CCH using a time division multiple access (TDMA) as a radio access between said base stations and said mobile stations; wherein each of said mobile stations comprises means for generating a packet in a f ormat that can be sent to a local area network (LAN), means for dividing the packet into segments, and means for adding a synchronization bit and a number identifying the mobile station to a first segment for generating segments, that each of said base stations comprises means, when one of said mobile stations sends the first segment to a transmittable RACH and said base station normally receives the segment, for notifying the mobile station number of said mobile station and information indicating that the mobile stations other than said mobile station are disabled from transmitting on the RACH on the down attendant CCH of the RACH, thereby notifying said mobile station of use right of the RACH and inhibiting other mobile stations acquiring the RACH from transmitting a packet and means for establishing up synchronization by using the first segment, that each of said mobile stations comprises means for adding numbers for identifying the segments,, and that said base station controller or each of said base stations comprises means for releasing the use right of the RACH upon reception of the last segment according to the segment identification numbers.
A radio data transmission system, comprising:

plurality of base stations; plurality of mobile stations; and 10 base station controller connected to a local area network (LAN) and having a channel configuration in which radio channels between each base station and a plurality of mobile stations consist of a control channel (CCH) and a plurality of communication c hanne ls (TCHs) wherein each of said base stations uses a plurality of TCHS as data communication channels using a random access method (RACHs); wherein said base station controller comprises means for assembling segments sent from one of said mobile stations into a packet in a fo=at that can be sent to the LAN, means for sending the packet to the LANr a conversion table for representing correspondence among mobile station numbers TNs identifying said mobile stations, addresses TAs identifying said mobile stations in the LAN, and channel numbers CNs identifying RACHs, means for searching said conversion table upon reception of an RACH use request from one of said mobile stations, means, if the TN of said mobile station does not exist in said conversion table, for registering the TN and the CN of an RACH specified by the channel assignment system as claimed in claim 9 in said conversion table, means, if the TN of said mobile station is registered, f or 'changing the CN corresponding to the registered TN to the CN of RACH specified by the channel assignment system, and means for changing said conversion table if upon reception of a packet over RACH from the mobile station identified by TN, the CN of the RACH dif f ers from the CN stored in said conversion table.
3. A radio data transmission system, comprising:

plurality of base stations; plurality of mobile stations; and base stat.ion controller connected to a local area network (LAN) and having a channel configuration wherein radio channels between each base station and a plurality of mobile stations consist of a control channel (CCH) and a plurality of communication channels (TCHs) wherein each of said base stations uses a plurality of TCHs as data communication channels using a random access method (RACHs); vherein said 'base stati-on controller romprises 'mean's-I upon reception of a packet destined f or one of said mobile stations from the LAN, for searching the conversion table for channel number TN of an RACH acquired by said mobile station and sending a call incoming notification with the TN of the packet destined for said mobile station to said base station managing the RACHr that said base station comprises means for passing on the packet incoming notification over down CCHs corresponding to all RACHs managed by said base station when receiving the packet incoming notification from said base station controller, that said mobile station compriies means, if said mobile station is shifting from one RACH to another for -20sending a packet, for stopping the channel shifting and returning to the channel shifting start RACH upon reception of the call incoming notification, that said base station controller comprises means for transmitting the packet to the RACH corresponding to the mobile station number of said mobile station stored in the conversion table in time Tp af ter sending the packet incoming notification, and that said base station comprises means for passing on the packet received from said 10 base station controller on a radio channel.
4. A radio data transmission system constructed and arranged to operate substantially as hereinbefore described with reference to and as illustrated in Figures 5 to I I of the accompanying drawings.