WO2001074017A1

WO2001074017A1 - Packet switched cellular network in which the network stations determine their addresses based on the geographic and altitude coordinates of their locations

Info

Publication number: WO2001074017A1
Application number: PCT/FI2001/000309
Authority: WO
Inventors: Kai Mustonen; Keijo Lähetkangas
Original assignee: Kai Mustonen; Laehetkangas Keijo
Priority date: 2000-03-31
Filing date: 2001-03-29
Publication date: 2001-10-04
Also published as: FI20000759A; FI20000759A0; AU2001250447A1; WO2001074017A8; FI114369B

Abstract

The invention relates to cellular packet switched telecommunication network. The basic network consists of subscriber specific network stations (NS1-NS9), which are mainly connected by radio. The address of a network station consists of its geographic coordinates and altitude coordinate. When the network station is taken into use, it determines its location by using e.g. GPS technique and registers itself to surrounding networks. The network station contains a small base station to enable the use of wireless terminals (MS11, MS12, MSnx). The network connection between the calling and called terminal, is realized via the network stations on the basis of the routing information in the network stations. The network operates in packet switched mode and beneficially in connection-oriented mode. Using upper layer network stations and long distance connections between them can interconnect separate basic networks. The wireless terminals can be equipped with routing feature to expand the coverage area of the basic network and to add capacity.

Description

Packet switched cellular network in which the network stations determine their addresses based on the geographic and altitude coordinates of their locations.

The invention relates to a cell structured and packet switched communication network.

There is a great amount of telecommunication networks in the world. Many different types that differ from each other by structure or functionality can be found among them. Traditional network has star structure in local level for example so that the terminals of the users are connected to concentrators and a number of concentrators is connected to a switch. There can be many switches so that the switches and transmission systems between them com- pose the central part of the network. Because of the concentrators and switches (and also because of the channeling equipment) the cabling costs of the network diminish crucially. A single network can function in a circuit- switched mode, when a transmission path composed of i.e. channels is reserved between two terminals only for said connection for the duration of the connection. A single network can also work in so-called packet-switched mode, in that case the connection between two terminals is virtual: Terminal sends information as specific form frames, alias "packets", and packets of different connections can go sequentially in the same channel. The receiver of each packet is indicated in the content of the packet. The receiver can be indi- cated so that the packet has a relatively short identifier of the network level connection, which has been agreed when the connection has been established, and the switches can route the packet to the correct direction on the basis of said identifier. This is called connection-oriented operation. Optionally each individual packet can contain the whole network address of the receiving terminal, and the switches of the network route the packet forward in the network on basis of this address. Initial connection establishment is then not needed, and this is called connectionless operation. The switches of the network operating this way are called normally routers. In router networks there are not said concentrators and the network is so called meshed, so there is plenty of direct connections between routers.

Mobile networks are enlargements of fixed networks. The network contains base stations, into which the terminals connect via radio connection. Normally the base stations are connected through a base station controller to a mobile network switch, and the mobile network switches connect to the other switches of the fixed telecommunication network. The operating area of the single base station is called as a cell. When the users of this kind cellular network are relatively scattered, the cells can be large. When the number of users increase, the capacity can be increased by reducing the cells, because in that case the channels in the frequency band given to the network can be used many times. In densely built environment, where there are plenty of network users, the separation of cells becomes relevant also in vertical direction. This prior art radio network structure is described in figure 1. It has a group of basic level cells as 111 and 112. They can be called as micro cells because they are small and are located relatively densely. Over the level of micro cells there are base stations which operating area is much bigger. In the figure two this way constructed macro cells 121 and 122 are seen. Macro cells assure the operation of the network. If the quality of some mobile communication becomes worse because of big amount of traffic or mobiles fast mobility, the mobile's serving base station can be changed from the basic layer to the up- per layer. In the figure 1 a mobile station 101 is marked with a dot in the area of one cell 111. According to above description, if needed, the hand over for the mobile station can be done from the base station of cell 111 to base station of macro cell 121. In the figure 1 also part of prior art fixed network is seen. In this belongs the BSC (base station controller), which has in the figure fixed connections to the base stations of three micro cells. There is a fixed connection from the base station controller to the mobile switching center MSC that has connections to the other switches of the basic network.

The drawback in the prior art networks is, that their structure is relatively heavy. Their dimensioning-, construction- and configuration costs are rela- tively high. The centralized maintaining of numbering schemes adds the inflexibility of the system. The fast increasing number of the users causes often situations when the capacity of the network isn't enough. Organizing the service to end-users requires necessarily network operators, which means that the costs of the users increase further. The purpose of the invention is to reduce mentioned disadvantaged related to the prior art. Characteristic to the network structure of the invention is presented in independent patent claim 1. Some of the beneficial applications of the invention have been presented in other patent claims.

The main idea of the invention is following: The basic network consists of subscriber specific network stations and connections between them which are mainly realized by radio. The address of a single network station consists of its geographical coordinates and its altitude coordinate. When a network station is taken into use, it defines its location automatically for example by using GPS (global positioning system)-technique and registers to the network surrounding it. The network station includes a small base station to enable the use of wireless terminals. Network connection between calling and called terminal is realized via network stations on the basis of their routing information. Also a wireless terminal can function as a router when making a connection. The network operates in packet-switched mode and beneficially in connection oriented mode. Separate basic networks can be interconnected via upper layer network stations and long distance connections between them. The wireless terminal has a home cell so that its address contains the address of the said home cell. Anyhow the terminal is identified and it can be used in the cell of any network station in the basic network.

The advantage of the invention is that the main network is easy to build and maintain: No massive switches are needed and the network grows "by itself when people purchase own network stations and take them into use. Basic network also configures itself automatically because of the addresses based on geographical coordinates. No centralized administration of addresses is therefore needed. In addition, an advantage is that in basic network no opera- tors are needed because of the reasons mentioned before. As a consequence the users of the network get no traffic charges from the use of the network. Furthermore, the advantage of the invention is that the basic network according to it is redundant and fault tolerant: A single fault doesn't remarkably reduce the capacity of the network. For example, if one network station were damaged, alternative routes to the connections going through it would easily be found. Furthermore, the advantage of the invention is that the increasing number of subscribers doesn't cause capacity problems in the network. In fact, an increase in the number of subscribers would enhance also the relative capacity of the network because of the added redundancy mentioned before. An advantage is also that mobile stations with routing capability can be used to enlarge the coverage area of the basic net and to improve capacity.

The term "subscriber" in this description and in the patent claims means the user of the network who manages the network station. One independent network station can naturally have other users than its holder. In the following the invention is described in more detail. In the description the attached figures are referred, in which

Figure 1 presents an example of the prior art network structure,

Figure 2 presents the structure of the basic network according to invention, Figure 3 presents the utilization of terminal in expanding the network,

Figure 4 presents the structure of network station as block diagram according to invention,

Figure 5 presents the structure of terminal as block diagram according to invention, Figures 6a,b present an example of connection establishment in the network according to invention,

Figure 7 presents extension possibilities of the network according to the invention, Figure 8 presents the three level extension of the network according to in- vention and

Figures 9a,b present an example about adoption of the network station's address.

The figure 1 was described in connection of prior art description.

In picture 2 there is an example of the structure of the network according to the invention. Nine network stations NS1-NS9 have been drawn there. Each one is owned by its "subscriber" and is therefore private. The cell of network station NSl has been shown with oval 211, and the cell of network station NS7 with oval 217. Each cell covers an area that typically has also other network stations, so the cells are strongly overlapping. Nearby network station NSl there are three terminals MS. From these terminals MSI 1 and MS 12 are in their home area, and terminal MSnx is a visiting terminal. From the described terminals the radio connection can be established at least to network station NSl. The radio range of the terminals is arranged optimally so, that they can reach the network station in certain area which is smaller than the network station cell area. Network stations relatively close to each other have a radio connection with each other. In the example of figure 1 these radio connections from network station NSl to network stations NS2-NS7 are marked with dotted lines inside the cell 211. In addition some other radio connections has been marked. Network stations NS8 and NS9 are in the example so far or in such places that there isn't any direct connection to them from network station NSl. Network stations NS2, NS3 and NS4 are geographically very close to each other, for example in flats on top of each other in the same high rising building. Their addresses have in this case difference only in the altitude coordinate.

In Figure 3 examples of network expansion according to invention with terminals is presented. Network stations NS31- NS35 and wireless terminals MS311, MS312 and MS3x can be seen. Network station NS31 has a direct connection to network station NS32. Instead network station NS35 is located so that the connection from network station NS31 to it can be made only via network stations NS32, NS33 and NS34. In the example of figure 3 mobile stations MS311 happens to be situated between network stations NS31 and NS35 so that both network stations can be reached from it. When network stations NS31 and NS35 have saved the information of mobile terminal MS311's existence in their areas, and the MS311 is equipped with routing capability, it can be used as a route for packets between stations NS31 and NS35 instead of normal longer route. The route via terminal MS311 can naturally be used as a redundant route between stations, even if the stations NS31 and NS35 had a direct route between themselves.

The terminal MS3x in Figure 3 is located so that it can't have a direct connection to any network station. The terminal MS312 happens to be located so that the connection from it can be made to station NS31 and to terminal MS3x. When the terminal MS312 has saved the information of the terminal MS3x's existence in it's coverage area, and when it has forwarded the information to the network, the terminal MS3x is connected to the network. Respectively the terminals can be chained: For example a terminal even more far from the station NS31 could be connected as terminal of the network via terminals MS3x and MS312. The terminals according to the invention, which have the routing capability, as the terminals MS311 and MS312 in figure 3, can also be equipped with automatic positioning to enhance the routing capability. Because of its features this kind of terminal can be called as a "semi network station".

The figure 4 is an example about the rough structure of the networks station according to the invention. The network station NS contains control unit CU, radio unit RU, options unit OU and wired interface unit WI. The control unit CU contain among other things the signaling software, which is needed in establishing and releasing the connections. This utilizes registers like HER (home environment register), RR (routing register) and MR (mobile register). The address information about the network stations to which the said network station has direct connections are in home environment register HER. In figure 4 the global positioning addresses GPA2, GPA3 and GPA4 of the network stations NS2, NS3 and NS4 are marked into home environment register HER according to example in figure 2. At each moment the home environ- ment register HER includes also the information of the visiting terminals in the cell of the said network station. According to example in figure 2 the address GPAnx of the visiting terminal MSnx is marked to the home environment register HER. The Routing Register RR includes information how the packet can be routed beneficially to the certain network station, which is more far away. The example in the figure has two cases: The packet to the network station NS8 will be sent to NS7, and the packet targeted to a network station NSn will be sent to network station NS5 and from there still to a network station NSi. In special cases, like when the connections start from the said cell and which are used repeatedly, the whole beneficial route with all the hops can be saved to the routing register.

When the network operates in connection-oriented mode, the routing register RR includes the register about connection-oriented information. This includes connection identifiers of different connections and their associated network addresses. When the network is big, the routing instructions to all stations are not worth of saving. Instead of that some concluding algorithm, which utilizes GPA addresses, is used for network stations, which are relatively far away.

Location information register MR has information of the network station's (NSl) own terminals location information at any moment. In the example of the figure the terminals MS 11 and MS 12 are marked to be in home cell and the terminal MS 13 in a cell Y. The location information of the cells, which mobiles are visiting, is received with the roaming function of the network.

The radio unit RU includes intermediate- and radio frequency parts to organize transmission between network stations and between network station and wireless terminals, and to enable positioning. The transmission to terminals may happen in the same or different frequency compared to transmission between network stations. So the radio unit and the antenna ANT connected to it are multi band.

The connection to local area network or directly to some public fixed network is in the wired interface unit WI. For example a connection to a network station, which is not reached by radio, can be made via this kind of interface. The WI unit may include also an interface for a fixed terminal of the network station.

The options unit OU enables the features, which are outside the basic specifi- cation of the network station. Outlining of the surrounding network structure with the help of learning process, organizing of alias names for addresses and in the case of upper layer network station the charging- and address service functions are examples of this kind of optional features.

In figure 5 there is an example about the rough structure of the terminal ac- cording to the invention. The terminal MS consists of control unit CU, radio unit RU, service unit SU and optional wired interface unit WI. The signaling software, which is needed in establishing and releasing the connections, is in the control unit CU. This utilizes registers RR (routing register) and TR (terminal register). The routing register RR contains routing information, which is copied from the network station into which the terminal is or has been connected. Terminal register is needed for situations, where the said terminal works as a link to the network station for such terminals, which are outside the coverage of all network stations. The terminal register TR includes the addresses of those terminals, which are connected to it. The radio unit RU in- eludes the intermediate and radio frequency parts required for using the radio link. Local network interface WI enables the connection to the network according to invention also then, when no connection is available via radio. The connection is realized via fixed networks to that kind of network station, which has a fixed network interface. Service unit SU realizes the functions, selected by terminal manufacturer, which ease and diversify the use of terminal.

Figures 6a, b show an example about the function of a network according to the invention. Figure 6a presents the functioning participants. There are three cells Cl, Cx and Cy, respective network stations being NSl, NSx and NSy, and two terminals MSI and MSx. Terminal MSx is in it's own home cell Cx. The cell Cl is the home cell of terminal MSI, but MSI is visiting cell Cy. The cells presented in the figure can be so far from each other, that the transmission between them requires routing via other cells. Terminal MSx "calls" terminal MSI. Figure 6b shows simplified signaling associated to the previous situation. First a call or connection request is sent from terminal MSx to network station NSx. The address of the called terminal MSI is naturally included into the connection request. On the basis of this address the network station NSx sends the connection request to the terminal MSl's home cell NSl. The net- work station NSl recognizes from its registers that terminal MSI is on that moment in the cell Cy. That information it has received earlier from the network station NSy immediately after, when terminal MSI has arrived to cell Cy and registered there. Network station NSl sends the location info of the terminal MSI to network station NSx. After that network station NSx sends the connection request to terminal MSl's roaming cell to the network station NSy, which passes it further to terminal MSI. Terminal MSI sends the response message, which is sent to sender of the original connection request, terminal MSx, on the basis of the address in the message. After that the network connection has been established between those two said terminals, which is available for the transmission of actual information. According to content of connection request- and response messages an identifier number for the said connection is agreed, which is remarkably shorter than the global addresses of the terminals. Identifier number is saved to the memory of network stations, which participate the information transmission, so that they can make the routing during the said connection only with the help of identifier number.

The network according to the invention includes also a network station hand over function: During the connection the terminal can start the change of the serving network station to a network station, which is more beneficial from the connection quality point of view.

In figure 7 there is a principle presentation about the extension possibilities of the basic network according to the invention. There are two basic networks Nl and N2, which are located reasonably far away from each other. In both networks there are a group of normal network stations. From the network Nl there is a direct connection to the upper layer network UNS11. Correspondingly from the network N2 there is a direct connection to upper layer network station UNS21. Between the upper layer network stations UNS11 and UNS21 there is in this example a satellite connection 701. Connection 701 is "direct" which means in this description and in patent claims, that other networks' network layer protocols are not needed for the transmission of information packets. Network layer's information packets may additionally be encapsulated in to different transmission connection frames during the transmission.

An alternative way to set up an upper layer connection between networks is presented in figure 7. In network Nl there is one upper layer network station UNS12, and in the network N2 there is another upper layer network station UNS22. Both network stations UNS12 and UNS22 have a connection to the Internet, via which the upper layer connection 702 connecting networks Nl and N2 can be made. Connection 702 is "switched" which means in this description and in patent claims, that the information packet of the network according to the invention is processed during the transmission according to other networks network layer protocols.

Network stations addresses include a certain part, which indicates if the network station is normal or upper layer network station. If the network station, which serves a calling terminal, notices that called terminal is located far away, it can directly select the upper layer network station address as the routing address.

In figure 7 there is also presented a connection 703 between a normal network station NS11 of network Nl and a normal network station NS21 of network N2. This can be for example some fixed connection of normal telecommunication network. With the help of arrangements like connections 701, 702 and 703, the network according to the invention becomes global. In practice the use of upper layer requires among other things arrangement of charging and thus operator action.

In figure 8 there is a principle presentation about extending the network according to the invention to three layers. There are basic networks Nl, N2, N3 and N4. Each of those have an upper layer network station, as the network Nl's station UNS1. Upper layer stations form between each other the network UNI. This has third layer, in this example the highest-level network station HNS1 (high network station). From the third layer network station HNS1 there are further connections to other same level network stations. Fig. 9a presents the function of the network station after taking it into use. In phase 900 the station is placed in to the final operation position or close to that, power is connected and e.g. RESTART button has been pushed. In Phase 901 the network station requires and receives form the surrounding and possible fixed connected network stations their addresses. At the same time the geographic positioning function is started, which is based on GPS technique in this example. The accuracy of the positioning is such in this example, that it gives the latitudes and longitudes of the globe with the accuracy of 1/100 minute of the longitude and latitude. In phase 902 the possible recep- tion of the location result is checked. If no result so far, the trial will continue. After the location has been determined, the altitude will be defined using some suitable technique (phase 903). After that, the address for the new network station is ready. In Phase 904, the determined address will be compared to existing addresses. If same address is already in use, the altitude coordinate will be redefined, according to agreed principle, so that the required difference between the new and the existing addresses is established. In phase 905, the station sends the newly defined address to the broadcast channel BCH, where other network station can receive it. In phase 906, the system waits for a predefined time ΔT, after which the address is sent again. This sequence will be repeated continuously.

Fig. 9b shows the registration of the addresses in the network stations. In phase 911 the network station observes the data in the broadcast channel. The observation is continued until a new address is noted (phase 912). In the next phase 913 the registers of the station are updated according to the new ad- dress. Then the process is continued in phase 911.

Some applications of the invention have been described above. The invention is not limited to them. The invention principle can be applied in several ways, within the limits of any of the independent patent claims.

Claims

1. Packet switched telecommunication network with cellular structure, and in which a network station acts as a functionary center in all of the cells, characterized by, that it is comprised of the above mentioned network sta- tions and radio connections between them, each cell connecting the above mentioned center network station and at least one other network station, and at least for the majority of the said network stations:

- the network station is subscriber specific,

- the network station has an address (GPA), which is based on the geographic coordinates of the network station and on the altitude coordinate,

- the network station is arranged to determine its own address automatically and to send the determined address to the broadcast channel of the network to be read by the network stations in the cell area of the said network station,

- the network station has an environment register (HER) for storing at least the addresses of the network stations in the cell area of the said network station and

- the network station has means for directing information packets to right direction outside the said cell.

2. Telecommunication network according to claim 1, characterized by, that the mentioned network stations (NSl) are arranged to operate as base stations for wireless terminals (MSI 1, MS 12, MSnx).

3. Telecommunication network according to claim 1, characterized by, that the said geographical coordinates contain latitude and longitude of the globe.

4. Telecommunication network according to claim 1, characterized by, that the said means for directing the packets to right direction comprise a routing register (RR) containing address information.

5. Telecommunication network according to claim 1, characterized by, that the said means for directing the packets to right direction comprise a routing algorithm.

6. Telecommunication network according to claim 1, characterized by, that it is arranged to operate on connection oriented mode, so that the information packets being sent from one terminal to another in the network con- tain, in stead of the network addresses, a connection-oriented identification number, which is selected when the connection is established.

7. Wireless terminal of the telecommunication network according to claim 1, characterized by, that it has an address, which contain a certain network station address and an additional identifier.

8. Wireless terminal according to claim 7, characterized by, that it's arranged to send its address and routing information to the network stations, which responds to the connection query of the said terminal.

9. Wireless terminal according to claim 8, characterized by, that it's ar- ranged to relay information packets between two network stations (NS31,

NS35).

10. Terminal (MS312) according to claim 7, characterized by, that it's arranged to establish a connection to another terminal and to relay information packets between the said other terminal (MS3x) and a network station (NS31).

11. Routing terminal according to claim 9 or 10, characterized by, that it's additionally arranged to define its address automatically using positioning system, for improving the routing.

12. Terminal according to claim 7, characterized by, that it contains addi- tionally an interface for connection to fixed telecommunication network.

13. Network station according to claim 1 characterized by, that it contains additionally an interface for connection to fixed telecommunication network, for arranging a connection to some other station through the said fixed network.

14. Telecommunication network (Nl) according to claim 1, characterized by, that it contains additionally a network station in upper network layer compared to the said network stations (UNS11, UNS12), for establishing a connection to another, geographically separated similar telecommunication network (N2).

15. Upper layer connection according to claim 14, characterized by, that it is a direct connection.

16. Upper layer connection according to claim 14, characterized by, that it is switched connection.

17. The connection according to claim 15 (701), characterized by, that it is realized via satellite.

18. The connection according to claim 16 (702), characterized by, that it is realized over the Internet.

19. Network station according to claim 14, characterized by, that it can be identified as an upper layer network station based on its address.

20. Telecommunication network according to claim 2, characterized by, that the radio communication between the said network stations and between the network stations and the terminals take place on same frequency range.

21. Telecommunication network according to claim 2, characterized by, that the radio communication between the said network stations and between the network stations and the terminals take place on different frequency range.