WO2001010086A1

WO2001010086A1 - Data transmission within a communication system

Info

Publication number: WO2001010086A1
Application number: PCT/US2000/017166
Authority: WO
Inventors: Timothy L. Moran; Jay P. Jayapalan; Bruce E. Urban
Original assignee: Motorola Inc.
Priority date: 1999-07-30
Filing date: 2000-06-22
Publication date: 2001-02-08

Abstract

During time periods when a user (113) accesses a RAN (101, 102), a routing address (IP address) is determined by the RAN (101, 102) using standard protocols. The IP address assigned by the RAN (101, 102) is sent to a Home Location Register (106, 107) serving the RAN (101, 102) along with the user's (113) mobile identity. The HLR (106, 107) retrieves the logical internet domain name of the user (113) and updates a Domain Name Server (103) with the appropriate IP address for the user's (113) logical name.

Description

DATA TRANSMISSION WITHIN A COMMUNICATION SYSTEM

Field of the Invention

The present invention relates generally to communication systems and, in particular, to data transmission within a wireless communication system.

Background of the Invention

Communication systems are well known and consist of many types including land mobile radio, cellular radiotelephone, personal communication systems, and other communication system types. Within a communication system, transmissions are conducted between a transmitting device and a receiving device over a communication resource, commonly referred to as a communication channel. To date, the transmissions have typically consisted of voice signals. More recently, however, it has been proposed to carry other forms of signals, including high-speed data signals. Methods for providing a data user with mobile access require the mobile unit to be assigned a permanent address (typically an Internet Protocol (IP) address). During time periods when the mobile unit is roaming in a foreign network, the data must be routed from the home network to the foreign network, usually via an IP tunneling process. The use of IP tunneling to deliver data can become quite involved an inefficient in that data sent to the foreign network is first sent to the home network, and then sent (tunneled) from the home network to the foreign network to be distributed to the mobile unit. For example, a mobile user that is assigned to a Chicago home network, and roams to a Dallas foreign network will have the same address on both networks. The Chicago network will receive data for the mobile unit, and then route the data to the Dallas network for distribution to the mobile unit.

An alternative to assigning a permanent IP address is to assign a temporary IP address to the mobile unit when the mobile unit transmits data. Although this method does solve many of the problems associated with tunneling data, data exchange can only be accomplished when the mobile unit initiates the exchange. More particularly, since the mobile unit has no IP address prior to when the mobile unit begins data transmission, data cannot be sent to the mobile unit. Therefore a need exists for data transmission within a communication system that allows for a mobile unit to be assigned an IP address without the establishment of an IP tunnel, and that allows for data to be sent to the mobile unit.

Brief Description of the Drawings

FIG. 1 is a block diagram of a communication system in accordance with the preferred embodiment of the present invention.

FIG. 2 is a block diagram of the domain name server of FIG. 1 in accordance with the preferred embodiment of the present invention. FIG. 3 is a flow chart showing operation of a radio access network of FIG.

1 in accordance with the preferred embodiment of the present invention.

FIG. 4 is a flow chart showing operation of the domain name server of FIG. 2 in accordance with the preferred embodiment of the present invention.

FIG. 5 is a flow chart showing operation of the communication system of FIG. 1 in accordance with an alternate embodiment of the present invention.

FIG. 6 is a flow chart showing operation of the domain name server of FIG. 2 in accordance with the alternate embodiment of the present invention.

Detailed Description of the Drawings

To address the above-mentioned need, a method and apparatus for data transmission within a communication system is provided herein. During time periods when a user accesses a radio access network, a routing address is determined by the radio access network using standard protocols. The routing address assigned by the radio access network is sent to a home location register serving the radio access network, along with the user's mobile identity. The home location register retrieves the logical internet domain name of the user and updates a domain name server with the appropriate routing address for the user^'s logical name.

Since a routing address is updated at a domain name server each time a user accesses a radio access network, the problems associated with the prior art are reduced. More particularly, data delivery can be accomplished to the mobile unit, and vice versa, since the mobile unit has a routing address immediately upon accessing a radio access network, without having to be active in a call. Additionally, since an IP tunnel is not established between the mobile unit^'s home network and the current network, the inefficiencies associated with sending data via an IP tunnel are reduced.

The present invention encompasses a method for data transmission within a communication system. The method comprises the steps of receiving an access from a mobile unit by a Radio Access Network (RAN), determining a logical address for the mobile unit, and assigning the mobile unit a temporary routing address. A Domain Name Server (DNS) is supplied the temporary routing address so that data can be appropriately routed to the mobile unit.

The present invention additionally encompasses a method for operating a Domain Name Server (DNS). The method comprises the steps of receiving a request from a server to provide a routing address for a user, accessing a database to determine if an routing address exists for the user, and determining an appropriate Radio Access Network (RAN) to query for the routing address. The appropriate RAN is queried for the routing address and the routing address is received from the RAN and supplied to the server.

Finally, the present invention encompasses a Radio Access Network (RAN) comprising a Home Location Register (HLR) having an access request as an input and outputting a routing address to a Domain Name Server (DNS).

Turning now to the drawings, where like numerals designate like components, FIG. 1 is a block diagram of communication system in accordance with the preferred embodiment of the present invention. As shown. communication system 100 comprises mobile unit (or user) 113, Radio Access Networks (RANs) 101-102. Domain Name Server (DNS) 103, Packet Data Network (PDN) 104. and content server 105. In the preferred embodiment of the present invention. RANs 101-102 utilize a Code Division Multiple Access (CDMA) system protocol as described in Cellular System Mobile unit-Base Station Compatibility Standard of the Electronic Industry Association/Telecommunications Industry Association Interim Standard 95A (TIA/EIA/IS-95C), which is incorporated by reference herein. (EIA/TIA can be contacted at 2001 Pennsylvania Ave. NW Washington DC 20006). However, in alternate embodiments RANs 101-102 may utilize other cellular communication system protocols such as, but not limited to, the next generation CDMA architecture as described in the UMTS Wideband cdma SMG2 UMTS Physical Layer Expert Group Tdoc SMG2 UMTS-L1 221/98 (UMTS 221/98), the next generation CDMA architecture as described in the cdma2000 International Telecommunication Union-Radiocommunication (ITU-R) Radio Transmission Technology (RTT) Candidate Submission document, or the next generation Global System for Mobile Communications (GSM) protocol, the CDMA system protocol as described in "Personal Station-Base Station Compatibility Requirements for 1.8 to 2.0 GHz Code Division Multiple Access (CDMA) Personal Communication Systems" (American National Standards Institute (ANSI) J-STD-008), or the European Telecommunications Standards Institute (ETSI) Wideband CDMA (W-CDMA) protocol.

Although not shown, RANs 101-102 include a number of network elements such as base stations, centralized base station controllers, and mobile switching centers. In the preferred embodiment of the present invention, all network elements are available from Motorola, Inc. (Motorola Inc. is located at 1301 East Algonquin Road. Schaumburg. IL 60196). It is contemplated that all elements within communication system 100 are configured in well known manners with processors, memories, instruction sets, and the like, which function in any suitable manner to perform the function set forth herein.

As shown, user 113 is communicating with RAN 101 via uplink communication signals 119 and RAN 101 is communicating with mobile unit 113 via downlink communication signals 116. RANs 101-102 are suitably coupled to DNS 103, PDN 104, and ultimately to server 105. In the preferred embodiment of the present invention PDN 104 is a service network, such as. but not limited to, a Public Switched Telephone Network (PSTN), an Integrated Switched Digital Network (ISDN), an International Telecommunication's Union (ITU) H.323 network, a Wide Area Network (WAN), a Local Area Network (LAN), or an internet network. Finally, server 105 is preferably a Personal Computer workstation. minicomputer, or large computing system that provides a central service to subscribers within the WAN. Typical examples of these services include automatic stock updates, automatic weather forecasts, automatic news updates etc. Operation of communication system 100 in accordance with the preferred embodiment of the present invention occurs as follows: When a user subscribes to data services, upon subscription, a wireless system operator populates HLRs 106 and 107 with the user's logical internet domain name (e.g. user@provider.com or user@company.com). In the preferred embodiment of the present invention HLRs 106 and 107 maintain database 155 of all appropriate logical internet domain names that have been assigned to users of the RAN, however in an alternate embodiment, the RAN may obtain the logical address from the remote unit in a real-time manner by either querying the mobile unit, or simply being supplied the address by the mobile unit. During time periods when user 113 accesses a RAN (i.e., during registration), a routing address (IP address) is determined by the RAN using standard protocols such as the Internet Protocol Control Protocol (IPCP) (IPCP is described in detail in the Internet Engineering Task Force (IETF) Request for Comment (RFC) 1332). The IP address assigned by the RAN is sent to a Home Location Register (HLR) serving the RAN along with the user^'s mobile identity. In the preferred embodiment of the present invention an Electronic Serial Number (ESN) is utilized as a mobile identity, however a Mobile Identification Number (MIN). Temporary Mobile Station Identity (TMSI). or International Mobile Station Identifier (IMSI). may be utilized as well. Along with the user's mobile identity, other typical cellular registration (location updating) information, such as cell identification, is sent to the HLR by the RAN. The HLR retrieves the logical internet domain name of the user and updates DNS 103 (existing external to RANs 101-102) with the appropriate IP address for the user's logical name.

An alternate embodiment the HLR updates the DNS such that the user^'s logical name is an alias to a canonical name. The IP address is associated with the new canonical name and stored in "a" DNS (possibly a DNS capable HLR) which supports queries for the canonical name.

In the preferred embodiment of the present invention each mobile unit is assigned a permanent logical address (e.g., name@provider.com) that is located - β-

within DNS 103. During times when an HLR 106, 107 updates DNS 103. an IP address associated with the logical address is updated. In the preferred embodiment of the present invention the IP address comprises an address that routes data to the RAN currently serving the mobile unit 113, and ultimately to user 113. It should be noted that address updates to DNS 103 occur each time mobile unit 113 registers with a RAN 101, 102. Thus, when mobile unit 113 is handed off from RAN 101 to RAN 102, DNS 103 will be updated by RAN 102 with an IP address that routes data to RAN 102.

Since an IP address is updated at a DNS each time mobile unit 113 accesses a RAN. the problems associated with the prior art are reduced. More particularly, data delivery can be accomplished to the mobile unit, and vice versa, since the mobile unit has an IP address immediately upon accessing a RAN. without having to be active in a call. Additionally, since an IP tunnel is not established between the mobile unit's home RAN and the current RAN, the inefficiencies associated with sending data via an IP tunnel are reduced.

FIG. 2 is a block diagram of DNS 103 of FIG. 1 in accordance with the preferred embodiment of the present invention. In the preferred embodiment of the present invention DNS 103 is a distributed server that resolves a known symbolic name address to its IP equivalent address for routing. As shown, DNS 103 comprises logic unit 202 and database 201. Database 201 comprises logical addresses for a plurality of mobile units, along with temporary routing addresses. Additionally, other information, such as the user's Mobile Identification Number (MIN). Temporary Mobile Station Identity (TMSI) address, International Mobile Station Identifier (IMSI) address, or possibly the point code of a single HLR for limited service is included within database 201. During operation DNS 103 periodically obtains updated routing address information from RANs 101 and 102 and updates the appropriate routing address within database 201. As shown, database 201 has routing address 111.1.1.1 associated with namel@mobile.com, and routing address 222.2.2.2 associated with name2@mobile.com. Since no routing address is associated with name3@mobile.com, the mobile unit with this logical address is not currently registered with a RAN.

FIG. 3 is a flow chart showing operation of RAN 101 of FIG. 1 in accordance with the preferred embodiment of the present invention. The logic flow begins at step 301 where RAN 101 receives an access from mobile unit 113. In the preferred embodiment of the present invention an access to RAN 101 comprises any first-time registration with RAN 101, whether via power on, or due to a handover to RAN 101 from another RAN. At step 305. RAN 101 determines the mobile unit's logical address, and assigns mobile unit 113 a temporary IP address within HLR 106. In particular, the serving system RAN selects an available IP address suitable for its data network and associates it with the mobile identity. Although it is envisioned that the steps of determining the mobile unit^'s address and assigning the mobile unit an IP address can be accomplished in many network elements, in the preferred embodiment of the present invention this task is accomplished within a centralized base station controller of the RAN accessed.

Although mobile unit 113 has been assigned an IP address, the address must be made known to PDN 104, and ultimately to other devices (e.g.. server

105) requesting communication with mobile unit 113. In order to accomplish this task, at step 310 HLR 106 updates DNS 103 with the current routing address for mobile unit 113. At step 315, HLR 106 determines if mobile unit 113 has terminated communication with RAN 101, and if not the logic flow returns to step 315, otherwise the logic flow continues to step 320. At step 320, HLR 106 instructs DNS 103 to remove the current routing address for mobile unit 113. and the logic flow ends at step 325. FIG. 4 is a flow chart showing operation of DNS 103 of FIG. 1 in accordance with the preferred embodiment of the present invention. The logic flow begins at step 401 where logic unit 202 receives an instruction from a RAN (e.g.. HLR 106) to update database 201 with an appropriate IP address for mobile user 113. Next, at step 405 logic unit 202 updates database 201 with the appropriate address for mobile user 1 13. At step 410, logic unit 202 receives an inquiry from server 105 requesting an appropriate routing address for data that is to be distributed to user 113. In the preferred embodiment of the present invention this inquiry comprises the logical address of user 113. Finally, at step 415 logic unit 202 retrieves the appropriate IP address by accessing database 201 and determining an associated IP address with the logical address. The IP address is then provided to server 105 via PDN 104. The logic flow ends at step 420.

FIG. 5 is a flow chart showing operation of communication system 100 of FIG. 1 in accordance with an alternate embodiment of the present invention. In the alternate embodiment of the present invention, routing addresses are not automatically assigned to mobile units when they access the system. More particularly, in order to conserve a RANs IP addresses, in the alternate embodiment of the present invention, IP addresses are assigned to mobile units only when data is to be sent to/from the mobile unit. The logic flow begins at step 501 where server 105 determines that data needs to be transmitted to mobile unit 113 and accesses DNS 103 to determine a routing (IP) address associated with a particular user. Additionally, at step 501 server 105 provides DNS 103 with a logical user name for mobile unit 113. At step 503 DNS 103 accesses database 201 to determine if an IP address exists for the logical address provided to DNS 103. If at step 503, a routing address exists for the logical address provided, then the logic flow continues to step 505 where the routing address is provided to server 105, otherwise the logic flow continues to step 507. At step 507, DNS 103 determines an appropriate RAN to query. In particular, DNS 103 determines an appropriate HLR within a RAN by accessing an internal database comprising a list of mobile user's logical names along with their associated Mobile ID(MID). By analyzing the MID the DNS can determine an appropriate HLR serving the mobile.

Continuing, at step 509, HLR 106 determines an appropriate IP address for mobile unit 113 and returns this address to DNS 103 and DNS 103 stores this address in database 201. The address is then provided to server 105 (step 505). Finally, at step 513 server 105 transmits data to mobile unit 1 13 utilizing the appropriate routing address.

Since an IP address is updated at a DNS each time data is to be transmitted to mobile unit 1 13, the problems associated with the prior art are reduced. More particularly, data delivery can be accomplished to the mobile unit since the mobile unit has an IP address assigned when data needs to be transmitted to the mobile unit. Additionally, since an IP tunnel is not established between the mobile unit's home RAN and the current RAN, the inefficiencies associated with sending data via an IP tunnel are reduced. FIG. 6 is a flow chart showing operation of the DNS of FIG. 2 in accordance with the alternate embodiment of the present invention. As discussed above, in the alternate embodiment of the present invention routing addresses are not automatically assigned to mobile units when they access the system, but instead routing addresses are '"requested" from the DNS when the DNS is queried for a routing address.

The logic flow begins at step 601 where DNS 103 receives a query for a routing (IP) address from server 105. In the alternate embodiment of the present invention the query takes place utilizing RFC 1034 and 1035 of IETF STD 13. Next, at step 603, DNS 103 accesses database 201 in order to determine the IP address for mobile unit 113. If an IP address for mobile unit 1 13 exists within database 201. the logic flow continues to step 605 where the IP address is returned to server 105. If. at step 603 it is determined that an IP address does not exist within database 201, then the logic flow continues to step 607 where an appropriate HLR is queried for an IP address for mobile unit 113. At step 611 an IP address is received for mobile unit 113. and the database is updated accordingly. The logic flow then continues to step 605 where the IP address is returned to server 105. The descriptions of the invention, the specific details, and the drawings mentioned above, are not meant to limit the scope of the present invention. For example, although in the preferred and alternate embodiments of the present invention all HLRs are shown existing apart from the DNS, one of ordinary skill in the art will recognize that the two entities may be combined. It is the intent of the inventors that various modifications can be made to the present invention without varying from the spirit and scope of the invention, and it is intended that all such modifications come within the scope of the following claims and their equivalents.

Claims

1. A method for data transmission within a communication system, the method comprising the steps of: i receiving an access from a mobile unit by a Radio Access Network (RAN); determining a logical address for the mobile unit; assigning the mobile unit a temporary routing address; and supplying a Domain Name Server (DNS) the temporary routing address so that data can be appropriately routed to the mobile unit.

2. The method of claim 1 wherein the step of receiving the access from the mobile unit comprises the step of receiving a handover to the RAN from a second RAN.

3. The method of claim 1 wherein the step of receiving the access from the mobile unit comprises the step of receiving a first-time access request to the RAN.

4. The method of claim 1 wherein the step of determining the logical address comprises the step of determining a logical internet domain name for the mobile unit.

5. The method of claim 1 wherein the step of assigning the mobile unit the temporary routing address comprises the step of assigning the mobile unit a temporary Internet Protocol (IP) address.

6. The method of claim 1 further comprising the steps of: determining if the mobile unit has terminated communication with the RAN; and instructing the DNS to remove the temporary routing address for the mobile unit from a database.

7. A method for data transmission within a communication system, the method comprising the steps of: receiving an instruction from a Radio Access Network (RAN) to update an internal database with a routing address for a mobile unit that has accessed the RAN; updating the internal database with the routing address; receiving an inquiry from a server requesting the routing address for the mobile unit; and providing the routing address to the server so that the server can appropriately rout data to the mobile unit.

8. A Radio Access Network (RAN) comprising a Home Location Register (HLR) having an access request as an input and outputting a routing address to a Domain

Name Server (DNS).

9. The RAN of claim 8 wherein the access request is caused by a handover from a second RAN to the RAN.

10. The RAN of claim 8 wherein the routing address is an Internet Protocol (IP) address.