US 20050282493 A1
A high speed data transfer system includes a WAU (201) which is utilized to provide high speed data access to satellite transferred data. The system is configured such that a plurality of data utilization devices (205) may access the high speed data via wireless links to the WAU (201). Advantageously, high speed data services may be provided to users without the users requiring individual satellite antennas.
65. A wireless access unit (WAU) for use in a wireless communications system having a plurality of data utilization devices located within a first service area, said WAU comprising:
a satellite communication transceiver subsystem for communicating with a satellite via a first wireless channel;
a WAU transceiver subsystem for communicating, via a second wireless channel, with a selected data utilization device in the plurality of data utilization devices, wherein said WAU transceiver subsystem is coupled to said satellite communication transceiver subsystem for enabling communication therebetween; and
a chassis supporting both said satellite communication transceiver subsystem and said WAU transceiver subsystem, wherein said chassis is adapted for mounting within said first service area.
66. The WAU, as claimed in
said chassis includes means for use in mounting said WAU to a pole.
67. The WAU, as claimed in
said chassis includes means for use in mounting said WAU to a building.
68. The WAU, as claimed in
said WAU has a size and weight that allows said WAU to be mounted within said first service area by a single installer.
69. The WAU, as claimed in
an infrastructure interface for providing a connection between said WAU and at least one wired communications service, wherein said infrastructure interface is coupled to said WAU transceiver subsystem for communication with said selected data utilization device.
This invention relates to bi-directional communication systems and methods, and in particular, to an integrated satellite based data communication system.
Business, retail, medical, university, transportation center and residential customers have a need for high data rate media transfer systems that link or interface to data utilization devices, such as personal computers (PCs) and workstations. As used herein, PCs will be understood to include personal computers, workstations and other similar data acquisition and/or origination terminals. A need exists for providing low cost wireless and wired high data rate/low delay information exchange to customer data utilization devices. Currently, no wireless high data rate bi-directional service exists between consumers, satellites, and wireline services. One problem with existing terrestrial systems is that the data transfer rate is relatively slow or alternatively is expensive. With current methods, data transfer is typically slow, resulting in long data-download times. Furthermore, real-time, high fidelity audio/video is often impractical given the current state-of-the-art. To provide high data rate capability to all potential users requires a high cost in capital equipment and assets or fixed-site operation to provide a system with widespread accessibility. So called “wireless” systems can provide significant high data rate transfers and widespread accessibility. However, no system presently exists incorporating inexpensive wireless transfer of satellite, terrestrial backbones, cellular data services, and wireline data which will provide economic access to such wireless and wired data sources. It is also desirable to provide for accessing information by wireless methods thereby providing freedom of movement for users and elimination of the cost of wired infrastructure.
Satellite based systems are under construction or are proposed which will make high data rate/low delay information transfer widely available. However, as presently planned or proposed such satellite systems require an expensive satellite transceiver and directional antenna at each user. What is needed are low cost software configurable satellite interfaces that leverage existing consumer equipment (e.g., laptop, palmtop, and desktop computers). For instance, at least one proposed system requires that each business and each residence have a stationary direct satellite link for the exchange of high speed data including multimedia data. In addition, there are many terrestrial data sources or sites with which it is desirable to have high speed data access. Such sites vary in the number of data consumers over the course of time. Hence, data demand can vary as customers enter or leave service areas. Therefore, it is further desirable to provide a system which will permit mobile access to high speed data sources and not have high associated costs as are required for existing data transfer systems and apparatus. It is also desirable that these data services provide self forming network services, depending upon spatial proximity of mobile users and data and bandwidth demands of stationary customers. Further, data information sources each use specific protocols for data routing transfer, packetizing, and switching. Therefore, there is a further need for a wireless interface to multiple data sources that provides a seamless, transparent interface between user and data service.
The invention will be better understood from a reading of the following detailed description in conjunction with the drawing figures in which like reference designators are use to identify like elements, and in which:
In accordance with the principles of the invention, a system is provided in which high data rate, low delay wireless data communication is provided to pluralities of users. Each plurality of users is served from a single, central wireless access unit (WAU). The WAU, in accordance with the invention, provides centralized wireless access for a plurality of users to satellite data communications and in addition, provides access to other high data rate services which may be wireless or wired. The invention advantageously provides for wireless communication between each data utilization device or PC and the WAU thereby permitting users to access the high data rate, low delay data from substantially any location within the range of the WAU. Thus, a system in accordance with the invention provides that a plurality of users may access satellite transferred data and wired data services, via one or more WAU devices, thereby allowing wireless bi-directional interchange of data. In a system in accordance with the invention, a plurality of users of high data rate, low delay wireless data access a proximity WAU which in turn accesses a satellite link or another WAU, or one or more of a number of wired and wireless services available within proximity of the WAU. In addition to independent access to one or more WAU devices, each user may also transfer data in a distributed peer-to-peer fashion.
In accordance with the principles of the invention, a Wireless Information Technology System (WITS) is provided which interfaces to multiple information sources and extends these services via wireless links, to users while providing self-forming network adaptability, frequency adaptability, modulation adaptability, interference suppression adaptability, overlay adaptability, and bandwidth adaptability. The system performs a seamless protocol transformation of subscriber data, providing a near transparent interface between consumer and desired information sources. A system in accordance with the principles of the invention provides for high data rate wireless information exchange to a plurality of users from a satellite antenna and associated satellite communication system, other terrestrial wireless systems or wired bi-directional data systems and sources. As used herein, the term “high data rate” is typically used to refer to data rates exceeding, for example, 400 kilobits per second (kbps).
In accordance with a further aspect of the invention, the WAU provides the ability to access information by wireless methods, thereby providing freedom of movement for users and elimination of the cost of a wired infrastructure between each user and the data communication services. By permitting wireless access between each PC and the WAU, a plurality of users located within wireless range of the WAU can access the high speed satellite, terrestrial microwave and cellular data services via the WAU. Access to multiple information sources and extension of these services via wireless links to the PC users is possible with the system in accordance with the invention. Each WAU and its associated users forms a cell within which users have wireless access to data services via the WAU. Since users can be mobile, one embodiment of the invention includes self-forming network adaptability whereby mobile nodes are “affiliated” with a nearby WAU automatically. As users move into other WAU cells, the cells perform handoff and affiliation functions for seamless data access. Advantageously, a single WITS WAU satellite transceiver microwave and cellular data subsystem or interface can service multiple users whether the users are mobile or stationary. In addition, wired services may be provided to those same users without the expense or difficulty of providing a wired connection to each user.
Turning now to
Satellite 101 may be accessed by a plurality of cells 103 that performs seamless protocol transformation and multi-port distribution to a plurality of users 105. Although only six cells 103 are shown, it should be appreciated that a larger or smaller number of terrestrial cells may be accessible by the satellite constellation. What is needed are cell-specific applications, whereby each cell will have a different type of data service tailored to the user requirements of each cell population. For example, medical campus requirements will use the invention for data transfer services that include: patient records, outpatient data, X-rays, CAT scans, MRI scans, provider consult data, insurance data links, transcription data, telemedicine services, billing, medical order transfer, medical research, and real time audiovisual medivac data. University campus services can use the invention for: records maintenance (e.g., transcripts, billing, etc.), library access, internet access, virtual professorships, research, remote audiovisual class attendance, inter campus housing, and inter university LANs. Neighborhood applications for the invention include: DSS delivery, movies on demand, internet access, telephony services, video telephone services, high-definition television (HDTV) services, real time on-demand CD audio, home shopping, home banking, profile based information delivery, and remote home environment management. Industrial campus applications of the invention include: wireless LANs, shop assembly and parts coordination, paging services, inventory control and RF tag services, telecommuting services, and remote sensor applications for electric, oil, gas, water, and other similar utilities. Commercial and retail campus services provided by the invention include: billing services, real time inventory control, real time shopping services, advertisement applications, real time delivery tracking, audiovisual customer service, reservation services, staff management and tracking, and security applications. Mobile applications of the invention include: vehicle tracking, real time location information, real time map delivery, and high speed passenger internet access.
For any data service provided by the invention, custom software will be provided to an individual user via disks 210 or directly over the high speed wireless link, once subscription confirmation has been received. This software will provide user access to the type of data desired. Hence, data utilization device 205 is understood to be a general purpose, software configurable appliance which is uniquely and dynamically tailored to user data requirements and cell populations. Each cell 103 has a WAU 201 and a corresponding group of users 105. Accordingly, each of the users 105 are able to communicate with satellite 101, or other high data rate services that are processed through gateway 104, by transferring data to and from WAU 201. This avoids the need for each user 105 to communicate directly with satellite 101, which would require a separate high cost transceiver and associated satellite antenna with proper placement for satellite visibility.
Turning now to
The position of WAU 201 within the cell 103 is a factor in determining the area or range of operation in which users may access WAU 201. In general, the higher the WAU 201 is mounted within the cell, the greater the possible range of coverage. In one approach, relatively small cells having relatively few users per cell are used. Using this approach, the WAU 201 can be mounted lower in the cell 103, such as on the top of a street light post 210. In the preferred embodiment, the nominal range of each WAU 201 will be in excess of one mile.
High density dwelling conditions, such as in high rise office and apartment buildings, typically prevent use of satellite tracking antennas by each resident. The use of a WITS WAU 201 in accordance with the invention addresses this limitation by allowing users to access data from satellites via the WITS WAU 201 which is located in a position for tracking and communicating with the satellites. The satellite access antenna may be of dish type, or, for more flexible satellite access, a phased array antenna.
Each user in the cell 103 typically has a data utilization device 205 which, for example, can take the form of a personal computer (PC) 203. WITS WAU 201 provides wireless access and distribution of high speed data services from satellites, for example, to a plurality of data utilization devices 205, typically including PC units 203 in a high density complex, and eliminates the need for wiring each building unit with satellite antenna capability. In a preferred embodiment, WITS WAU 201 will also incorporate an omnidirectional antenna for data transfer to/from user terminals, although other antenna configurations may also be appropriate.
Each PC 203 is a platform that accepts software files designed to program and interact with a subscriber interface module (SIM) 204. SIM 204 may take the form of, or be included within, a PCMCIA type card. In an alternate embodiment, SIM 204 may be a separate portable device that connects using a PCMCIA bus slot of PC 203. SIM 204 includes a transceiver 207 to provide the wireless connection to WITS WAU 201 for data services. SIM 204 includes (or can be connected to) an antenna 206 of conventional design for the frequency band of interest and desired polarization (e.g., circular polarization) or sectored antennas. Transceiver 207 performs all modulation and demodulation functions for transmit and receive communications to the WITS WAU 201. In this regard, SIM 204 can, in one embodiment, receive commands and/or configuration data from the PC 203 for use in processing any of a number of different waveforms.
In the illustrated embodiment of the invention, data transfers between the WITS WAU 201 and transceiver 207 provide minimum interference to existing terrestrial voice and data services by utilizing spread spectrum transmission and/or by utilizing portions of the spectrum that are not currently occupied. Accordingly, in a preferred embodiment, transceiver 207 is a spread spectrum transceiver or high data rate transceiver, both with multiple access capability.
PC 203 may also include drive 208 for receiving one or more disks 210 having specific wireless application software stored thereon. This allows the PC 203 to be upgraded to higher capacity and more bandwidth efficient waveforms. In addition to link-specific software, drive 208 and disks 210 also provide functionality specific to the type of data service being utilized by the consumer.
Turning now to
A seamless protocol transformation processor 307 is utilized to provide for protocol transformations between data protocols from: (i) satcom transceiver subsystem 303, (ii) wired services 212, (iii) terrestrial wireless services, (iv) terrestrial microwave services, and (v) cellular/land mobile services and the data protocols used to link to user PCs 203 with wireless signals.
A wireless modem distribution processor (WDP) 309 is coupled between protocol transformation processor 307 and RF modules 317 and 319 which are in turn coupled to antenna 321. A processor 325 is coupled via bus 323 to satcom wired infrastructure interface 305, seamless protocol transformation processor 307, wireless modem distribution processor 309, and RF modules 317 and 319. Processor 325 includes associated memory which is not shown, but which is familiar to those skilled in the art. As will also be understood by those skilled in the art, although the block diagram of
Satellite antenna 200 is used to establish and maintain the link to a satellite 101. Antenna 200 is coupled in conventional fashion to the satcom transceiver subsystem 303. Satcom transceiver 303 is of conventional design and provides a high data rate bi-directional link to satellite constellation 101 via antenna 200.
WITS WAU 201 is interfaced with wired services 212 via satcom wired infrastructure interface 305 and wireless WAU link 213. Processor 325 includes selection capability to select a data route via satellite, terrestrial microwave, cellular data, WAU peer-to-peer, or the various wired services 212 based on cost, information content, and delay profiles selected and transferred to the WITS WAU 201 by means of automatic user node affiliation, and maintained in WITS WAU memory. Alternatively, software in the WITS WAU 201 can automatically select one service from multiple choices based upon predetermined parameters or algorithms. The software can also provide adaptive functionality for waveforms transmitted via antenna 321 and wireless WAU link 213 including, but not limited to, frequency, modulation and bandwidth.
WITS WAU 201 supports software configurable modem technology that provides a family of wireless signals such as DSPN/CDMA, QAM/TDMA, PSK/OFDM, FH/CDMA, and other wireless multiple access techniques that are compatible with the local data utilization devices. Further, various wireless interfaces may be provided through the use of programmable modem modules 311, 313, 315, and 316. Modem modules 311-315 are typical examples of how WDP 309 may be programmed (i.e., to support, for example, code division multiple access (CDMA), time division multiple access (TDMA), and frequency division multiple access (FDMA)). It should be understood that other wireless multiple access schemes are also possible as needed. In a preferred embodiment, hybrid spread spectrum modulation is used via hybrid SS module 316. In this preferred embodiment, hybrid modulation includes both frequency hop (FH) and direct sequence (DS) methods in order to minimize WITS service impact on existing wireless services, while simultaneously reducing the interference impact of these existing services on the WITS-delivered data.
Satcom transceiver subsystem (STS) 303 has the capability to acquire, track, demodulate, and maintain contact to LEO and HEO satellites, and/or other platforms, which may include Geosynchronous Earth Orbiting (GEO) satellite up/downlinks. STS 303 is of conventional design. Interface 305 comprises conventional interfaces to STS 303, terrestrial microwave and cellular data services, and to the ISDN, cable and fiber networks. By providing connection to these services at WITS WAU 201, the data services provided by these various high data rate services are provided to all users of the WITS WAU 201 without the necessity of providing connections directly from each satellite antenna or terrestrial wireless systems to each individual user.
WITS WAU 201 may operate with a variety of service-dependent protocols. Accordingly, to facilitate the flexibility of operating with the various protocols, WITS WAU 201 includes a seamless protocol transformation (SPT) processor 307 for providing a seamless protocol transformation such that whatever signal protocol is received from the sources coupled to interface 305 is transformed to the proper data link layer format for wireless transmission to the users 105 of WAU 201. SPT processor 307 receives a satcom, microwave, cellular, or wired signal from the appropriate transceiver interfaces 305 and 307 and transforms it up the open signaling interface (OSI) protocol stack layer to provide a multiple access system that allows connectivity to many users. SPT processor 307 performs bi-directional physical and upper layer mapping and transformations to provide compatibility with the final stage media transmission with appropriate mobile identification. The functionality of SPT processor 307 includes ATM (asynchronous transfer mode)-to-wireless, ISDN-to-wireless, Cable-to-wireless, fiber optic-to-wireless, terrestrial wireless-to-wireless, and other protocol transformations. SPT processor 307 provides transformation between the WDP 309 and interface 305.
WDP 309 is a software configurable modem for providing a family of wireless signals, such as frequency hop (FH)/CDMA, DSPN/CDMA 311, QAM/TDMA 313, PSK/OFDM 315 and other multiple access techniques. The various signals are utilized to provide modulation signals information to a transceiver comprising RF modules 317, 319 which are operable in various modulation arrangements, such as PSK-OFDM, SSPN, SSFH, and other high data rate modes. Spread spectrum techniques allow operation in areas of the spectrum that are already occupied by other systems, without interfering with the other systems. Modulation formats are software selectable within WITS WAU 201 and are remotely programmable as well as field programmable.
WITS WAU 201 provides high data rate satellite signals and information to its local area with minimum interference to existing terrestrial voice and data services. WDP 309 and RF modules 317 and 319 facilitate spread spectrum signals, including for example, frequency hopped signals, direct sequence signals, or hybrid signals, whereby spread spectrum signal technology is utilized to allow existing narrowband signals for cellular and land mobile radio (LMR) traffic, among others, to occupy the same frequency bands without impact on these services. Spread spectrum signals support multiple access schemes to increase user density on each channel and improve spectrum reuse. Spread spectrum signals are especially effective in overcoming frequency selective fading, common to urban mobile environments. A high data rate capability facilitates transfer of video and other large files with low delay to the end user.
Turning now to
In operation, WITS WAU 201 is capable of automatic spectral awareness and management for the frequency channels used in the wireless distribution of information to each user. Processor 325 operates in cooperation with RF modules 317 and 319 to search for the unoccupied spectrum when operating in areas that will not allow fixed or preassigned operating bands and channels. The designated operating bands are scanned and spectral activity estimates of this possible channel space are developed. Decision criteria are applied by processor 325 to select the proper operating center frequencies and to periodically assess and reallocate to new bands as the background wireless systems dictate.
The unique spectral awareness capabilities of the WITS WAU 201 allow selection of the operating bands within the coverage of the SIM 204. This reduces interference on the existing wireless systems not related to WITS WAU 201. Dynamic spectrum awareness knowledge of transmission activity occurring simultaneously on other channels is used to prevent interference.
The above-described capabilities facilitate automatic spectrum planning and co-site contention resolution during system setup and service initiation. In this scenario, throughput preservation and system overlay capability is at odds with fixed-frequency paradigms. Growing spectral clutter is evidenced by increasing commercial services, such as PCS, AMPS-IS136, IS-95, GSM, DSS, Iridium, Celestri, and Teledesic. Historically, spectrum utilization has tended toward the lower frequencies occupying a tiny fraction (i.e., ˜1%) of available bandwidth. As commercial spectral usage increases into the next century, communication systems will inevitably face constricting limits on information capacity. Without a means and method for signal coexistence, communication systems will be forced to move to ever higher bands of operation. In a cluttered environment, anywhere from 100 MHz to 2 GHz of bandwidth will be needed to ensure high multimedia throughput and multi-access performance. What is needed are new technologies that overcome the bandwidth limitation problem by adaptively increasing data throughput without adding bandwidth. The system of the present invention solves the bandwidth/throughput problem via adaptive spectrum exploitation (ASE). ASE will enable automatic time sharing of intermittently used or unused spectral regions. Methods used by ASE are well within the capabilities of software programmable radios.
In a preferred embodiment, adaptive spectrum exploitation is performed using transform domain methods on a joint time frequency (JTF) basis.
Surveillance and monitoring is gained via analysis of the spectrum using feature plane transformations, such as amplitude projections, phase projections, time projections, detection information, and signal correlation data. These transformations are analyzed to provide information specific to each discrete signal within the analysis bandwidth, such as type, frequency range, transmit probabilities, and signal strength. The feature plane transformations are computed from the JTF matrix H of order n, m, where n represents a contiguous time index and m represents a contiguous spectral index, as is indicated by Equation 1.
Parameter extraction algorithms well within the capabilities of programmable radios are used to compute a snapshot of spectral activity corresponding to H. The following structure comprises a candidate parameter set for one embodiment of the invention:
In addition to the adaptive exploitation of spectral “holes”, it may also be desirable to employ the spectrum scanning and analysis in, a tagging mode. In this manner, signals within the band of interest may be identified and tagged such as military, cellular, satcom, broadcast, global positioning system (GPS), and pager. Data of interest may also include TDOA estimates and network identification tags. This emitter analysis mode will provide network managers with expanded spectral awareness for each cell in the network. This information is communicated via the satellite/platform or wireline links shown in
At sufficiently high frequencies with wide bandwidths of operation, the spectral planning may allow the WITS WAU in the cell to access the spectrum in a uniform distribution. In this straightforward mode, the MAI characteristics will depend primarily on the number of users accessing the selected bandwidth. Naturally, higher frequency propagation loss characteristics will result in smaller cells with fewer users per cell, while increased bandwidths will enhance system robustness to interference. In this mode of operation, the transmission characteristics will include both frequency hopping and pulse concealment methods in order to avoid interference with fixed communication systems.
WITS WAU 201 solves the difficult problem of interpreting one protocol down to a critical OSI layer and inserting another protocol layer for the new transmission format without affecting the message information content. WITS WAU 201 combines the signal processing and signal protocols associated with STS 303, WDP 309, and the SPT processor 307 with a common bus and hardware/software platform to reduce delay, maintain the high data rates and multiple access capability, and choose the proper cost method.
WITS WAU 201 collects and maps the user profile information for best “information contouring.” This feature filters information to reduce the amount of bandwidth or transmission time allocated to a wireless user. This also reduces the information load on the user.