EP1413091A2

EP1413091A2 - A multi-network mobile communication system

Info

Publication number: EP1413091A2
Application number: EP02731835A
Authority: EP
Inventors: Kumar Ramaswamy
Original assignee: Thomson Licensing SAS
Current assignee: Thomson Licensing SAS
Priority date: 2001-05-30
Filing date: 2002-05-20
Publication date: 2004-04-28
Also published as: KR20040002967A; WO2002098057A8; BR0210029A; JP2004537195A; CN1543730A; WO2002098057A2; WO2002098057A3; MXPA03010868A; AU2002303776A1; CA2447919A1

Abstract

A communication system for communicating via the Internet, includes a portable communications device, and a plurality of networks interconnecting, at least occasionally, the internet with the portable communications device. An intelligent content server is also interconnected to the Internet. A network management entity, is interconnected to the intelligent content server, and chooses which network is to be used for communicating between the intelligent content server and the portable communications device.

Description

SEAMLESS COMMUNICATIONS THROUGH OPTIMAL NETWORKS

Field of the Invention

The present invention relates generally to mobile communications platforms and more specifically to communications optimization using an intelligent network selection.

Background of the Invention

Mobile or cellular telephone devices are configured to communicate with a plurality of antennas, either ground or satellite based, which are ultimately connected to the traditional telephone system. Regardless of the specific path used there is a direct link between the cellular telephone and the telephone system communication network. Digital cellular telephone devices are further capable of transmitting to and receiving digital data from a digital data network, such as the Internet, with which the telephone system is interconnected. Such devices have been termed personal communications systems (PCS) devices. Such enhanced PCS devices can request, receive and display information from the internet such as maps, e-mail, text, web pages, audio and video files.

One problem associated with such enhanced capabilities is the bandwidth required to transmit such large volumes of data. Problems with scheduling and routing of data transmissions, as well as inefficient allocation of data transmission capacity, are present in many existing data communications networks. For example, the global interconnection of computer networks known as the Internet routes data packets with the anticipation that the packets will eventually be delivered to the intended receiver but it is not uncommon for packets to be lost or delayed during transmission. Further, the internet does not differentiate between different types of data being transmitted.

Data packets requiring delivery within a certain time frame such as real time audio or video communications receive no preference in transmission over packets that generally do not require a particular time of delivery, such as electronic mail. Data packets carrying important information in which packet loss cannot be tolerated, such as medical images, receive no greater priority than other data packets . Because all data packets are viewed as equally important in terms of allocating transmission resources, less^' critical transmissions such as e-mail may serve to delay or displace more important and time sensitive data.

Capacity for data transmission in existing data communications networks is often inefficiently allocated. In some instances transmission capacity or bandwidth is allocated to a particular user according to a fixed schedule or particular network architecture, but the available bandwidth is not actually used. In other instances, a user is precluded from transmitting a burst of data that, for the moment, exceeds the user's bandwidth allocation. Existing data communications networks often lack mechanisms whereby bandwidth may be allocated on demand. The current cellular telephone system uses relatively low bandwidth signaling techniques on the order of fifty kilobits per second. Graphical information such as maps and pictures require relatively wide bandwidths in order to achieve reasonable response times . Video and audio files require even higher bandwidths for adequate response times . With limited spectrum resources, the cost of bandwidth on a relatively narrow band network can be high.

Current television signal broadcasting systems provide relatively wide bandwidth capability on the order of twenty megabits per second for each six megahertz wide television channel. Terrestrial frequency bands in the United States include almost four hundred megahertz of available spectrum. Terrestrial broadcast channels typically have a reception radius of approximately seventy miles, dependent largely on local terrain.

Direct digital satellite television broadcasting systems can also provide digital channels which can be used for digital information transmission. An example of such a system is disclosed in United States Patent No. 6,366,761, entitled PRIORITY BASED BANDWIDTH ALLOCATION AND BANDWIDTH ON DEMAND IN A LOW EARTH ORBIT SATELLITE DATA COMMUNICATIONS NETWORD, issued on April 2, 2002 to Montpetit. Digital data from these channels are receivable over a much wider area typically including tens of thousands of square miles . These channels are not completely used. Thus there is a vast amount of unused television broadcast spectrum available for other uses. 88 Some data which will be requested by a user of a PCS

89 device will be unique to that user, such as an e-mail 90 addressed only to that user. Other data will be of

91 simultaneous interest to a large number of users, such

92 as weather data or stock market quotations . Other

93 information will be of widespread simultaneous interest

94 only at certain times, such as IRS tax forms during the

95 second week of April. The Internet and the associated IP 96 protocols will be expected to enable the increasing

97 demand for data. Network connectivity can be established

98 through a variety of means including connecting to a ^•

99 broadband modem (cable, DSL or satellite) through wired

100 or wireless means, or by connecting to a nomadic network

101 such as offered by wireless LAN standards, or by

102 connecting to a mobile network. Current bandwidth for

103 cellular telephone devices is barely sufficient to

104 provide unique information to a particular PCS device as

105 such information is requested, and more efficient methods

106 of accessing the appropriate network for the bandwidth

107 actually needed must be found if all of the available 108 bandwidth is not to become exhausted by the increasing

109 number of users.

110 Within a single network the mechanism or protocol

111 needed to connect to that network in order to obtain a

112 range of services is a straightforward problem with known

113 solutions. However, when one must traverse between

114 different networks the problem of making a seamless

115 transition is substantial. For example, in second

116 generation cellular networks it is often possible to

117 connect to a different network on a per session basis. 118 Unfortunately, the possibility of optimizing

119 bandwidth at the packet level is not available because 120 the mechanism for communicating across networks has no

121 common protocol layer. In the Internet, the commonly

122 used protocol is termed IPv4 which has a set of tools

123 that enables mobility management. These set of protocols

124 are termed Mobile IP protocols. Several enhancements

125 to the IPv4 protocols have resulted in a second

126 generation termed IPv6. In addition to an expanded

127 address space of 128 bits instead of the 32 bits used by

128 IPv4, there are several features that enable better

129 mobility management. Mobility can be managed by using

130 the static IP addressing schemes in IPv6. In IPv4, due

131 to the scarcity of address space, dynamic and local IP

132 address assignment is often used. The efficiency of

133 address management is expected to be better in IPv6 which

134 will result in better service overall. An example of a

135 mobile system using IPv6 is disclosed in United States

136 Patent No. 6,172,986, entitled MOBILE NODE, MOBILE AGENT

137 AND NETWORK SYSTEM, issued to Watanuki et al . on January

138 9, 2001.

139 Data requested by the user may be of a time critical

140 nature and need to be delivered with strict time

141 constraints. Alternatively, data may also be downloaded

142 with less severe time constraints. The former calls for

143 Quality of Service (QoS) constraints that need to be

144 supported by the network. The latter is the typical

145 download model for Internet content and is termed a best-

146 effort delivery. Finally, data may also be delivered

147 with a time delay. Examples could include music or

148 multimedia which the user wishes to view at a later time. 149 This category represents the most flexibility afforded 150 from a network optimization and usage viewpoint.

151 Given the existence of the many networks, bandwidths

152 and accessibility variables briefly alluded to in the

153 foregoing, a need exists for a mechanism that allows the

154 user to seamlessly roam or transition between these

155 networks, based on a calculation of the needed bandwidth, 156 message priority, and bandwidth cost, such that the

157 minimum required bandwidth at the lowest cost is always

158 selected.

159 Summary of the Invention

160 In accordance with the principles of the present

161 invention, a communication system for communicating via

162 the Internet, includes a portable communications device,

163 and a plurality of networks interconnecting, at least

164 occasionally, the internet with the portable

165 communications device. An intelligent content server is

166 also interconnected to the Internet. A network

167 management entity, is interconnected to the intelligent

168 content server, and chooses which network is to be used

169 . for communicating between the intelligent content server

170 and the portable communications device .

171 In such a communications system, the problem of

172 optimizing network selection by choosing the most cost

173 effective available bandwidth is addressed by

174 implementing the portable communications device as a

175 portable intelligent multiple network platform. The

176 platform includes multiple front end interfaces, with

177 each interface corresponding to a type of available 178 network, such as a home network interface, broadcast

179 network interface, nomadic network interface and a mobile

180 network interface. The home network interface is

181 typically plugged into a broadband modem, while the other

182 interfaces utilize an antenna terminal to perform

183 wireless communications .

184 Within the platform each network interface is

185 interconnected to a network data processing layer capable

186 of transmitting and receiving data via either the IPv4 or

187 IPv6 protocol. For large files requiring substantial

188 bandwidths, such as multimedia applications, the network

189 data processing layer is interconnected to a discrete 190 backend applications processor which processes and

191 buffers the data stream.

192 Each network interface transmits to and receives

193 data from a base station or network termination dedicated

194 to that particular type of network. In turn, each such

195 base station or termination has an appropriate connection 196 to the Internet. Also connected to the Internet is an

197 intelligent content server which is interconnected to a

198 network management entity. In order for the intelligent

199 content server to communicate with the portable

200 intelligent multiple network platform, the platform

201 registers into any of the available networks through any

202 physical layer having a return channel.

203 The platform can function with the existing mobile

204 IPv4 protocols or can use the static IPv6 global

205 addressing scheme. The platform communicates with the

206 intelligent content server and informs the server of its 207 current IP address and its current specific multi- 208 networking capabilities. The intelligent network

209 management entity chooses the appropriate network to use

210 for each packet which is to be transmitted or received

211 based on optimizing criteria such as priority, desired

212 transmission quality, required bandwidth and cost.

213 When the portable platform leaves the current

214 network within which it is operating (typically due to

215 physically travelling beyond the range of the current

216 network) , the portable platform automatically searches

217 for and tries to connect to the next best (based on the

218 optimization criteria) network. When a new connection is

219 successfully accomplished, the portable platform sends 220 information to the network management entity regarding

221 its current connection. In response to this information,

222 the intelligent network management entity routes

223 subsequent packets through the newer optimum network

224 route. This process can be managed at either a per-

225 packet or per-session level.

226 Brief Description of the Drawings

227 Figure 1 is a block diagram illustrating portable

228 communications network selection optimizing system

229 according to the principles of the present invention; and

230 Figure 2 is a block diagram of a personal

231 communications system device according to the principles

232 of the present invention, which may be used in the system

233 as illustrated in Figure 1. 234 Detailed Description of the Invention

235 Figure 1 is a block diagram of a mobile

236 communications system including a multiple network

237 portable platform 10 which is capable of bidirectional

238 transmission and reception with either a broadband modem

239 12 or with any of a plurality of wireless communications

240 networks via antennas 122, 126 and 128. In practice the

241 antennas 122, 126 and 128 may be a single physical

242 antenna with appropriate matching networks or it may be

243 one or more antennas in close physical proximity. The

244 antenna 122, for example, is responsive to digital

245 cellular telephone signals from, for instance, a cellular

246 telephone mobile network termination or base station 22.

247 The antenna 122 is bidirectionally coupled to a mobile

248 interface circuit 120.

249 As also seen in Figure 2, the mobile interface

250 circuit 120 is coupled to a direct data input terminal of

251 a microprocessor 118. A direct data output terminal of

252 the microprocessor (μP) 118 is coupled to an input

253 terminal of the mobile interface 120. An audio output

254 terminal of the microprocessor 118 is coupled to an input

255 terminal of the speaker 114. An output terminal of a

256 microphone 112 is coupled to an audio input terminal of

257 the microprocessor 118. An output terminal of a keypad

258 116 is coupled to a control input terminal of the

259 microprocessor 118.

260 The microprocessor operates in a known manner under

261 the control of an application program stored in memory

262 such as a Read Only Memory (ROM) in the microprocessor 263 118. In particular, the microprocessor is programmed to

264 operate as a data processing layer 130 utilizing the both

265 the current Internet Protocol version 4 (IPv4) and the

266 still developing next generation Internet Protocol

267 version 6 (IPv6) . The layer 130 may include a Quality of

268 Service (QoS) program as is well known to those of

269 ordinary skill in this field.

270 The microprocessor 118 also includes a backend

271 applications processor 14 which is capable of

272 bidirectional communication with the Internet Protocol

273 layer 130. The processor 14 serves as a buffer and

274 decoder for data received by microprocessor 118, and is

275 particularly useful for processing data having a

276 multimedia content such as audio and video files. The

277 backend processor 14 may also be a discrete circuit or

278 combination of integrated circuits that are external to

279 the microprocessor 118 but which are still mounted on the

280 multiple network portable platform 10.

281 The platform 10, as described above, operates in a

282 known manner to allow a user to make telephone calls.

283 The user manipulates the keys on the keypad 116 to 284 instruct the microprocessor 118 to cause the mobile

285 interface circuit 120 to connect to an external network,

286 such as the Internet 30, or a mobile telephone

287 communications network via the mobile base station 22.

288 The keypad 116 generates dialing tones specifying the 289 desired telephone number or instructional code.

290 Alternatively, signals may be received from the Internet

291 30 or from the cellular telephone network indicating that

292 someone is attempting to call the portable platform 10. 293 In response to these signals, the microprocessor 118

294 conditions the mobile interface circuit 120 to connect to

295 the network and complete the call.

296 In either event, signals representing spoken

297 information from the microphone 112 are digitized by the

298 microprocessor 118, and the digitized signal is

299 transmitted through the mobile interface 120 and the

300 antenna 122 to the mobile network base station 22.

301 Simultaneously, signals received by the antenna 122 from

302 the base station 22, and representing received digitized

303 speech information from the other party, are received by

304 the mobile interface 120, converted to a sound signal by

305 the microprocessor 118 and supplied to the speaker 114.

306 As described above, the multiple network platform 10

307 also provides the capability of requesting and receiving

308 information from a computer, typically via the internet.

309 Data representing requested information may be generated

310 by the user from the keypad 116, which may have more keys

311 than illustrated in Figure 2. The information request

312 is supplied by the microprocessor 118 to any of the

313 network interfaces available on the network platform 10.

314 For example, the platform 10 may include not only a

315 mobile interface 120, but also a home network interface

316 110, a nomadic network interface 16, and a broadcast

317 network interface 18. Depending on which network is

318 available for use, the information request is transferred

319 to either a broadband modem 12 or one of the antennas

320 122, 126 or 128.

321 Regardless of the network in use at a particular

322 time, the information request is transmitted to the 323 Internet 30. Also supplied by the common layer 130 is a

324 status report regarding which of the network interfaces

325 16, 18, 110 and 120 is currently in communication with

326 its associated network. Each of these networks will have

327 unique characteristics associated with its particular

328 network path. These characteristics will include the

329 bandwidth of the network path, the monetary cost of using 330 the network, the data transmission speed available, the

331 quality and reliability of the network, the geographic

332 coverage of the network and the type of data best suited 333 for transmission via the particular network path. By 334 transmitting the current universe of network

335 availability, a recipient may be able to select the most

336 appropriate network for transmission of return data.

337 The information transmitted by platform 10 to the

338 Internet 30 will be received by a server machine such as

339 intelligent content server 27 which contains the

340 information desired by the user of the portable platform

341 10. Interconnected to the content server 27 is a network

342 management entity 26 which receives the network

343 availability or status report from platform 10. The

344 management entity 26 is programmed to optimize the

345 selection of the network via which its associated content

346 server 27 will transmit and receive data to and from the

347 platform 10.

348 There exist two possible modes of transmitting the

349 desired information from the server 27. The first mode

350 is a unicast mode in which the server's data is intended

351 only for a specific user's platform 10. The second

352 possible mode is a mul ticast mode in which the server's 353 data is intended for simultaneous transmission to a

354 plurality of platforms 10.

355 In either case the objective of the server 27 is to

356 transport P packets to the platform 10 by routing the

357 data through the backbone or internal structure of the

358 internet 30 to the "edge" 31 of its global computer

359 network, and to continue the data transmission from the

360 edge 31 across the chosen communications access network

361 20, 21, 22 and/or 25 to the platform 10.

362 In order for the network management entity 26 to

363 optimize its choice of a particular network from the

364 universe of available networks, the goal for the unicast

365 mode is to minimize the expression:

3 66 Minimize P_j∑((^χi + yi)Ni) subject to Pj = P j

367 where

368 Xj is the cost of transporting each data packet

369 through the internet 30 to its edge 31 for the ith access

370 line;

371 y-j is the cost of transporting each packet through

372 the respective access networks, e.g. 20, 21, 22, 25;

373 P_j is the number of packets transported on link i; 374 and

375 Ni is the number of users on the ith link requesting

376 the content of server 27.

377 The unicast expression can be solved as an

378 optimization problem using standard optimization

379 techniques, which will result in reducing the cost of 380 transporting each packet through the entire network, that

381 is, through the internet 30 and through the following

382 communications network 20, 21, 22 or 25. To enable

383 quality of service, the cost structure for each segment,

384 x± and y± used earlier are appropriately reflected and

385 the optimization problem is solved with the new numbers.

386 For the multicast case, the goal is to minimize the 387 following expression:

388 Minimize j ^pj∑{^χi + ^yi ) subject to Σ*J

389 This expression is identical to the unicast mode

390 except that the penalty incurred for multiple users

391 requesting server content (N ) is removed. This

392 expression also can be optimized using well known

393 optimization techniques. Each optimization may be

394 performed on either a per packet or per session basis.

395

Claims

1. A communication system for communicating via the Internet, comprising: a portable communications device; a plurality of networks, each network inter- connecting, at least occasionally, the internet with the portable communications device; an intelligent content server, the content server being interconnected to the Internet; and a network management entity, the network management entity being interconnected to the intelligent content server, the network management entity choosing which network is to be used for communicating between the intelligent content server and the portable communications device.

2 The communications system of claim 1, wherein the portable communications device comprises a plurality of network interfaces for establishing a communications link with each of the plurality of networks, respectively.

3. The communications system of claim 2, wherein the portable communications device further comprises a microprocessor programmed to process data via any of the network interfaces .

4. The communications system of claim 3, wherein the network management entity is programmed to choose the network to be used for communicating with the portable device based on available bandwidth of each of the plurality of networks .

5. The communications system of claim 4, wherein the network management entity evaluates a cost associated with each network when choosing the network to be used for communicating with the portable communications device .

6. The communications system of claim 5, wherein the network management entity evaluates a quality-of- transmission value associated with each network when choosing the network to be used for communicating with the portable communications device.

7. The communications system of claim 6, wherein the network management entity evaluates the network to be used for communicating with the portable communications device for each data packet to be transmitted between the intelligent content server and the portable communications device.

8. The communications system of claim 6, wherein the network management entity evaluates the network to be used for communicating with the portable communications device for each data transmission session.

9. The communications system of claim 8, wherein the microprocessor is programmed to transmit all information to and from each network interface by using a common Internet protocol layer.

10. The communications system of claim 9, wherein the microprocessor is programmed: to determine which of the plurality of networks is operational; to transmit information representing which of the plurality of networks is operational to the network management entity.

11. A data transmission optimization system for use in multi-network environments, comprising: an intelligent content source (27) ; an intelligent network management entity (26) interconnected to the intelligent content source; a multi-network platform (10) interconnected to a plurality of communications networks, the multi-network platform transmitting a communications network status report to the intelligent management entity, the intelligent management entity selecting a communications network (20, 21, 22, 25) for transmission of data from the intelligent content source to the multi-network platform.

12. The data transmission optimization system of claim 11 wherein the intelligent management entity selects one of the communications networks based on an optimization algorithm that includes network bandwidth as a variable.

13. The data transmission optimization system of claim 11 wherein the optimization algorithm evaluates network cost of data transmission as a variable.

14. The data transmission optimization system of claim 11 wherein the optimization algorithm evaluates network quality of data transmission as a variable.

15. The data transmission optimization system of claim 11 wherein the intelligent management entity selects one the communications networks for each data transmission session with the multi-network platform.

16. The data transmission optimization system of claim 11 wherein the intelligent management entity selects one of the communications networks for each data packet transmitted to the multi-network platform.

17. A method of optimizing data transmission between a portable platform and an intelligent content server by optimizing a communications network selection in a multi- network environment, comprising the steps of: determining which communications networks are connected to the portable platform; transmitting a communications network status report to the intelligent content server; causing a network management entity to evaluate characteristics of the communications networks connected to the portable platform; and causing the network management entity to select a communications network based on the evaluated characteristics; and transmitting data from the intelligent content server to the portable platform via the selected communications network.

18. The method of claim 17, further comprising the step of evaluating characteristics of the communications networks for each data transmission session.

19. The method of claim 17, further comprising the step of evaluating characteristics of the communications networks for each data packet to be transmitted.

20. The method of claim 17, wherein data is transmitted from the intelligent content server to the portable platform via a common internet protocol layer