The present invention relates to a localized installation of a gateway system, for private or limited public wireless telephone communication, with all telephone calls going into and coming out of the localized wireless gateway system utilizing a public packet switched data network such as the Internet.
The written description uses a large number of acronyms to refer to various services and system components. Although generally known, use of several of these acronyms is not strictly standardized in the art. For purposes of this discussion, acronyms therefore will be defined as follows:
ADPCMxe2x80x94Adaptive Differential Pulse Code Modulation
ARPAxe2x80x94Advanced Research Projects Agency
ARPANETxe2x80x94Advanced Research Projects Agency NETwork
ASxe2x80x94Autonomous Systems
ATMxe2x80x94Asynchronous Transfer Mode
CDMAxe2x80x94Code Division Multiple Access
CELPxe2x80x94Code Excited Linear Predictive coding
COxe2x80x94Central Office
CODECxe2x80x94digital CODer and DECoder
CRENxe2x80x94Corporation for Research and Educational Networking
CPUxe2x80x94Central Processing Unit
CT-2xe2x80x94Cordless Telephone two
DECTxe2x80x94Digital European Cordless Telecommunication System
DHCPxe2x80x94Dynamic Host Configuration Protocol
DNSxe2x80x94Domain Name Server
DTMFxe2x80x94Dual Tone Multi-Frequency
FDDIxe2x80x94Fiber Distributed Data Interface
FMxe2x80x94Frequency Modulation
GAOxe2x80x94Government Accounting Office
GSMxe2x80x94Global System for Mobile
HLRxe2x80x94Home Location Register
IPxe2x80x94Internet Protocol
ISDNxe2x80x94Integrated Services Digital Network
ISPxe2x80x94Internet Service Provider
LANxe2x80x94Local Area Network
MACxe2x80x94Media Access Control
MILNETxe2x80x94MILitary NETwork
NSFNETxe2x80x94National Science Foundation NETwork
PCxe2x80x94Personal Computer
PCSxe2x80x94Personal Communications Service
PABXxe2x80x94Private Automatic Branch Exchange
PBXxe2x80x94Private Branch Exchange
PPPxe2x80x94Point to Point Protocol
PRIxe2x80x94Primary Rate Interface (for ISDN)
PSTNxe2x80x94Public Switched Telephone Network
RAMxe2x80x94Random Access Memory
RFxe2x80x94Radio Frequency
ROMxe2x80x94Read Only Memory
TCPxe2x80x94Transmission Control Protocol
SONETxe2x80x94Synchronous Optical NETwork
SMDSxe2x80x94Switched Megabit Data Service
SMDIxe2x80x94Simplified Message Desk Interface
TDMAxe2x80x94Time Division Multiple Access
VLRxe2x80x94Visitor Location Register
VSELPxe2x80x94Vector-Sum Excited Linear Predictive coding
In our increasingly mobile society, there has been an ever increasing demand for mobile communications to allow a person to roam freely while making and receiving telephone calls from virtually any location. A wide range of wireless systems are in use today and more are now scheduled for near term future deployment, including cellular telephone systems (both analog and digital) and lower power portable handset type systems now commonly referred to as personal communications service (PCS) systems.
Public cellular telephone systems and the emerging low-power, digital cellular PCS systems provide a high degree of mobile communications, as subscribers roam over large geographic areas. However, such systems are expensive to deploy, and as a result, air time charges for use of such systems are high. A number of applications have been recognized where wireless communications are desirable, but implementation of a full public cellular telephone system is unnecessary. This specification refers to these more limited systems as xe2x80x98localizedxe2x80x99 wireless or cordless telephone type communications systems.
For example, U.S. Pat. No. 4,980,907 to Raith et al. discloses a wireless communication system with roaming capabilities. Each portable radio terminal can operate at a subscriber""s residence as part of residential equipment, or in a commercial subscriber""s business area as an extension to a private automatic branch exchange (PABX). When away from the normal residential or business location, however, the portable radio terminal can operate through public transceivers referred to as telepoint terminals. Each residential installation, PABX and telephone terminal connects through a telephone line or trunk to an exchange of a public switched telecommunication network (PSTN).
U.S. Pat. No. 4,875,231 to Hara et al. discloses a radio telephone system, which includes a base station connected to a telephone exchange and a plurality of mobile stations. The mobile stations communicate with the base station through a control channel and a number of communication channels.
Each of U.S. Pat. Nos. 4,965,849 and 5,014,295 to Kunihiro discloses a cordless telephone system, wherein the master station connects to two outgoing telephone lines. The master station includes a number of base transceiver units for simultaneously communicating with a number of portable wireless handsets.
U.S. Pat. Nos. 4,878,238 and 5,020,094 to Rash et al. describe a cordless telephone network which allows each hand-held cordless telephone unit to be used with any of a number of strategically located base units, for example located at truck stops, rest areas along interstate highways, convention centers and the like. A base unit connects via a telephone line to a conventional commercial telephone network. The base unit includes an FM transmitter, FM receiver, CPU and a telephone line interface circuit. The Rash et al. Patents mention that it would be possible to have multiple base units at one location, each one being attached to a different land line and each one operating on a cordless telephone channel.
As shown by the above description, the localized cordless telephone systems utilized in the prior art have all relied on an existing public telephone network to transport communications outside of the cordless telephone systems themselves. In such a situation, for example, a long distance call typically would go through a local exchange carrier to the point of presence of an interexchange carrier for routing to the area of the called party. Although fees and billing arrangements vary widely, each carrier imposes some form of charge for its handling of a portion of such a call. The long distance and international charges by the interexchange carriers, in particular, can be quite high.
Concurrent with developments in wireless communications, outlined above, attention recently has been directed to implementing a variety of communication services, including voice telephone service, over the worldwide packet switched data network now commonly known as the Internet. The Internet had its genesis in U.S. Government programs funded by the Advanced Research Projects Agency (ARPA). That research made possible national internetworked data communication systems. This work resulted in the development of network standards as well as a set of conventions, known as protocols, for interconnecting data networks and routing information across the networks. These protocols are commonly referred to as TCP/IP (transmission control protocol/internet protocol). The TCP/IP protocols were originally developed for use only through ARPANET but have subsequently become widely used in the industry. TCP/IP is flexible and robust. TCP takes care of the integrity, and IP moves the data.
The Internet provides two broad types of services: connectionless packet delivery service and reliable stream transport service. The Internet basically comprises several large computer networks joined together over high-speed data links ranging from ISDN to T1, T3, FDDI, SONET, SMDS, ATM, OT1, etc. The most prominent of these national nets are MILNET (Military Network), NSFNET (National Science Foundation NETwork), and CREN (Corporation for Research and Educational Networking) In 1995, the Government Accounting Office (GAO) reported that the Internet linked 59,000 networks, 2.2 million computers and 15 million users in 92 countries. However, since then it is estimated that the number of Internet users continues to double approximately annually.
In simplified fashion the Internet may be viewed as a series of packet data switches or xe2x80x98routersxe2x80x99 connected together with computers connected to the routers. The information providers constitute the end systems which collect and market the information through their own servers. Access providers are companies such as UUNET, PSI, MCI and SPRINT which transport the information. Such companies market the usage of their networks to the actual end users.
FIG. 3 shows a simplified diagram of the Internet 349 and various types of systems typically connected thereto. Generally speaking the Internet consists of Autonomous Systems (AS) type packet data networks which may be owned and operated by Internet Service Providers (ISPs) such as PSI, UUNET, MCI, SPRINT, etc. Three such AS/ISP networks appear in FIG. 3 at 310, 312 and 314. The Autonomous Systems (ASs) are linked by high bandwidth Inter-AS Connections 311, 313 and 315. Information providers 316 and 318, such as America Online (AOL) and Compuserve, connect to the Internet via high speed lines 320 and 322, such as T1/T3 and the like. Information providers generally do not have their own Internet based Autonomous Systems but have or use Dial-Up Networks such as SprintNet (X.25), DATAPAC and TYMNET.
In some cases, the information provider 316 or 318 operates a host server or network of servers that their customers access by dial-up connection. If a customer wants information over and above that offered by the provider, the host server provides a tunnel connection through to the high speed link and the Internet 349. Other parties may connect into the network 349 at some other point and access information offered by provider 316 or 318 through the network 349.
By way of current illustration, MCI is both an ISP and an information provider, SPRINT is an ISP, and the MicroSoft Network is an information provider using UUNET as its ISP. Other information providers, such as universities, are indicated in exemplary fashion at 324 and are connected to the AS/ISPs via the same type connections here illustrated as T1 lines 326. Parties access information on servers of providers 324 via the Internet 349. Corporate Local Area Networks (LANs), such as those illustrated in 328 and 330, are connected through routers 332 and 334 and high speed data links such as T1 lines 336 and 338. Laptop computers 340 and 342 are representative of various personal computers and the like connected to the Internet via the public switched telephone network (PSTN) and are shown connected to the AS/ISPs via dial up links 344 and 346.
Recently, several companies have developed software for use on personal computers to permit two-way transfer of real-time voice information via an Internet data link between two personal computers, for example between PCs 340 and 342. In one of the directions, the sending computer converts voice signals from analog to digital format. The software facilitates data compression down to a rate compatible with modem communication via a POTS telephone line, in some cases as low as 2.4 kbits/s. The software also facilitates encapsulation of the digitized and compressed voice data into the TCP/IP protocol, with appropriate addressing to permit communication via the Internet 349. At the receiving end, the computer and software reverse the process to recover the analog voice information for presentation to the other party. These programs permit telephone-like communication between Internet users.
PCs having voice communication capabilities can conduct two-way, real-time audio communications with each other, in a manner directly analogous to a two-way telephone conversation. However, the actual signals exchanged between two such terminal devices go through the public packet data network. Typically, such communications at least bypass long distance interexchange carriers.
Internet based telephone programs have relied on servers (not separately shown) coupled to the Internet to establish voice communication links through the networks. Each person active on the network, who is willing to accept a voice call, must register with a server. A calling party can call only those persons registered on the voice communication server.
The development of the Internet, particularly voice telephone communication over the Internet, has been separate from efforts to develop and deploy localized wireless or cordless telephone type communications systems. For example, the PCs and server systems on the market today apparently have not permitted calling through the Internet to wireless telephone subscribers, particularly when roaming. As a result, a need still exists to find an effective cheaper alternative to the transport of calls to and from localized wireless systems via telephone carrier networks. More specifically, a need exists to provide a localized wireless or cordless telephone type communications system which can at least selectively provide voice traffic transport over a public packet switched data network, such as the Internet. A need further exists for systems and call processing methodologies to facilitate easy calling and efficient routing of calls to and from such a system, via the public packet data network.
The present invention meets the above stated needs by providing a localized wireless gateway offering cordless telephone service, including voice communication service, via a public packet network such as the Internet.
Thus, in one aspect, the present invention relates to a localized wireless gateway system. The inventive gateway system includes a plurality of base station transceivers. These transceivers provide two-way wireless voice frequency communication signals, in a standard compressed digital data format, to and from wireless telephone terminals within a local area. Each of the base station transceivers is built around a client computer, typically a client PC. The gateway system includes a local area data network coupled to the client computers, and a server computer interfaced to the local area data network. The server computer includes an interface to the public packet data network. The server computer processes the standard compressed digital data format signals for two-way packet communication via the public packet data network. The server computer also performs necessary signaling through the public packet data network to establish two-way voice communication sessions through the public packet data network.
In the preferred implementation, the base station transceivers each include a digital modulator, a digital demodulator, and an interface coupling the client computer to the local area data network. The wireless telephone terminals utilize a wireless telephone communication protocol for digitized and compressed voice communication, preferably code excited linear predictive (CELP) coding or vector-sum excited linear predictive (VSELP) coding. The base station transceivers and the server pass audio communication signals in this format to and receive similar signals from the public packet data network. If the public packet data network utilizes Internet Protocol (IP) packets, for example, the server may perform two-way IP packet processing and exchange signals with the base station in sequential order in the protocol utilized on the local area network, such as Ethernet or Asynchronous Transfer Mode (ATM).
The preferred implementation utilizing a local area network offers other types of communications. Data devices coupled to the local area network can exchange data messages and/or access the public packet data network via the server. Any such data devices having voice communication capabilities also can conduct various telephone-type communications, between two or more such devices, to and from wireless telephone terminal devices and to and from devices accessed via the server and the public packet data network.
Alternative implementations may utilize a direct connection of the public packet data network to one or more of the base station transceivers. In such a case, the data links to and from the transceivers would utilize IP packets.
Thus, in another aspect, the present invention contemplates a base station transceiver facilitating communication of cordless or wireless telephone signals over a public packet data network. The transceiver includes a central processing unit as well as a digital modulator and a digital demodulator. The central processing unit controls the modulator and demodulator to provide wireless communication of digitized and compressed audio signals for a plurality of wireless terminal devices over a predetermined air interface. The base station transceiver also includes a network interface to a data network carrying data packets in a predefined packet data protocol. The data network may be a local area network (LAN) coupled to the public packet data network, or the data network may itself be the public packet data network. A wireless gateway system may comprise one or more of these base station transceivers.
In each implementation, the wireless gateway system eliminates the need for switched telephone communication except for those cases where the distant party is accessible only via a public switched telephone connection. The public packet data network will include a PSTN gateway for establishing communications with such parties, and the link from the wireless terminal device to that gateway will still utilize the public packet switched data network.
The preferred implementation provides local data communications over the LAN as well as voice communication features analogous to those offered by a private branch exchange, in a single integrated communication system. That implementation also offers data access to the public packet switched data network, e.g. the Internet. The preferred implementation further offers telephone type calling capabilities, without calls to and from the system going through either a local telephone carrier or an interexchange carrier coupled directly to the particular wireless gateway system.
Additional objects, advantages and novel features of the invention will be set forth in part in the description which follows, and in part will become apparent to those skilled in the art upon examination of the following or may be learned by practice of the invention. The objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.