Showing papers on "Wireless published in 1998"

V-BLAST: an architecture for realizing very high data rates over the rich-scattering wireless channel

Abstract: Information theory research has shown that the rich-scattering wireless channel is capable of enormous theoretical capacities if the multipath is properly exploited In this paper, we describe a wireless communication architecture known as vertical BLAST (Bell Laboratories Layered Space-Time) or V-BLAST, which has been implemented in real-time in the laboratory Using our laboratory prototype, we have demonstrated spectral efficiencies of 20-40 bps/Hz in an indoor propagation environment at realistic SNRs and error rates To the best of our knowledge, wireless spectral efficiencies of this magnitude are unprecedented and are furthermore unattainable using traditional techniques

Spatio-temporal coding for wireless communication

Abstract: Multipath signal propagation has long been viewed as an impairment to reliable communication in wireless channels. This paper shows that the presence of multipath greatly improves achievable data rate if the appropriate communication structure is employed. A compact model is developed for the multiple-input multiple-output (MIMO) dispersive spatially selective wireless communication channel. The multivariate information capacity is analyzed. For high signal-to-noise ratio (SNR) conditions, the MIMO channel can exhibit a capacity slope in bits per decibel of power increase that is proportional to the minimum of the number multipath components, the number of input antennas, or the number of output antennas. This desirable result is contrasted with the lower capacity slope of the well-studied case with multiple antennas at only one side of the radio link. A spatio-temporal vector-coding (STVC) communication structure is suggested as a means for achieving MIMO channel capacity. The complexity of STVC motivates a more practical reduced-complexity discrete matrix multitone (DMMT) space-frequency coding approach. Both of these structures are shown to be asymptotically optimum. An adaptive-lattice trellis-coding technique is suggested as a method for coding across the space and frequency dimensions that exist in the DMMT channel. Experimental examples that support the theoretical results are presented.

Overview of spatial channel models for antenna array communication systems

Abstract: Spatial antenna diversity has been important in improving the radio link between wireless users. Historically, microscopic antenna diversity has been used to reduce the fading seen by a radio receiver, whereas macroscopic diversity provides multiple listening posts to ensure that mobile communication links remain intact over a wide geographic area. In later years, the concepts of spatial diversity have been expanded to build foundations for emerging technologies, such as smart (adaptive) antennas and position location systems. Smart antennas hold great promise for increasing the capacity of wireless communications because they radiate and receive energy only in the intended directions, thereby greatly reducing interference. To properly design, analyze, and implement smart antennas and to exploit spatial processing in emerging wireless systems, accurate radio channel models that incorporate spatial characteristics are necessary. In this tutorial, we review the key concepts in spatial channel modeling and present emerging approaches. We also review the research issues in developing and using spatial channel models for adaptive antennas.

Wideband DS-CDMA for next-generation mobile communications systems

Abstract: Wideband wireless access based on direct sequence code division multiple access aimed at third-generation mobile communications systems is reviewed. W-CDMA is designed to flexibly offer wideband services which cannot be provided by present cellular systems, with various data rates as high as 2 Mb/s. The important concept of W-CDMA is the introduction of intercell asynchronous operation and the pilot channel associated with individual data channels. Intercell asynchronous operation facilitates continuous system deployment from outdoors to indoors. Other technical features of W-CDMA include fast cell search under intercell asynchronous operation, fast transmit power control, coherent spreading code tracking, a coherent RAKE receiver, orthogonal multispreading factor forward link, and variable-rate transmission with blind rate detection. The introduction of the data-channel-associated pilot channel allows W-CDMA to support interference cancellation and adaptive antenna array techniques that can significantly increase the link capacity and coverage. This article presents the radio link performance evaluated by computer simulation. Field experiment radio link performance results are also presented.

Efficient use of side information in multiple-antenna data transmission over fading channels

Abstract: We derive performance limits for two closely related communication scenarios involving a wireless system with multiple-element transmitter antenna arrays: a point-to-point system with partial side information at the transmitter, and a broadcast system with multiple receivers. In both cases, ideal beamforming is impossible, leading to an inherently lower achievable performance as the quality of the side information degrades or as the number of receivers increases. Expected signal-to-noise ratio (SNR) and mutual information are both considered as performance measures. In the point-to-point case, we determine when the transmission strategy should use some form of beamforming and when it should not. We also show that, when properly chosen, even a small amount of side information can be quite valuable. For the broadcast scenario with an SNR criterion, we find the efficient frontier of operating points and show that even when the number of receivers is larger than the number of antenna array elements, significant performance improvements can be obtained by tailoring the transmission strategy to the realized channel.

Vertical handoffs in wireless overlay networks

Abstract: No single wireless network technology simultaneously provides a low latency, high bandwidth, wide area data service to a large number of mobile users. Wireless Overlay Networks – a hierarchical structure of room-size, building-size, and wide area data networks – solve the problem of providing network connectivity to a large number of mobile users in an efficient and scalable way. The specific topology of cells and the wide variety of network technologies that comprise wireless overlay networks present new problems that have not been encountered in previous cellular handoff systems. We have implemented a vertical handoff system that allows users to roam between cells in wireless overlay networks. Our goal is to provide a user with the best possible connectivity for as long as possible with a minimum of disruption during handoff. Results of our initial implementation show that the handoff latency is bounded by the discovery time, the amount of time before the mobile host discovers that it has moved into or out of a new wireless overlay. This discovery time is measured in seconds: large enough to disrupt reliable transport protocols such as TCP and introduce significant disruptions in continuous multimedia transmission. To efficiently support applications that cannot tolerate these disruptions, we present enhancements to the basic scheme that significantly reduce the discovery time without assuming any knowledge about specific channel characteristics. For handoffs between room-size and building-size overlays, these enhancements lead to a best-case handoff latency of approximately 170 ms with a 1.5% overhead in terms of network resources. For handoffs between building-size and wide-area data networks, the best-case handoff latency is approximately 800 ms with a similarly low overhead.

Wireless remote synchronization of data between PC & PDA

Abstract: The present invention utilizes wireless communication paths between a PC (600) and a Personal Digital Assistant (PDA) (602) to synchronize data files between the PC and the PDA. Example wireless communication paths include a one; way paging network, a two-way paging network (152), a Cellular Digital Packet Data (CDPD) network, and a cordless telephone network. Automated updating of remote files is accomplished by invisibly updating using a paging or CDPD network, e.g., either after each change to the data file, after a series of changes to the data file, after exiting the scheduling application program, at predetermined intervals and/or even on-demand. The invention provides a simple and efficient wireless way to synchronize data files on separate computers which do not require a fixed, direct connection to each other, such as a direct connection through the PSTN, infrared link, or wired or wireless LAN type connection. The synchronization of data files can be updated on a frequent, inconspicuous and convenient basis.

Space-time coded OFDM for high data-rate wireless communication over wideband channels

Abstract: There has been an increasing interest in providing high data-rate services such as video-conferencing, multimedia Internet access and wide area network over wideband wireless channels. Wideband wireless channels available in the PCS band (2 GHz) have been envisioned to be used by mobile (high Doppler) and stationary (low Doppler) units in a variety of delay spread profiles. This is a challenging task, given the limited link budget and severity of wireless environment, and calls for the development of novel robust bandwidth efficient techniques which work reliably at low SNRs. To this end, we design a space-time coded orthogonal frequency division multiplexing (OFDM) modulated physical layer. This combines coding and modulation. Space-time codes were previously proposed for narrowband wireless channels. These codes have high spectral efficiency and operate at very low SNR (within 2-3 dB of the capacity). On the other hand, OFDM has matured as a modulation scheme for wideband channels. We combine these two in a natural manner and propose a system achieving data rates of 1.5-3 Mbps over a 1 MHz bandwidth channel. This system requires 18-23 dB (resp. 9-14 dB) receive SNR at a frame error probability of 10/sup -2/ with two transmit and one receive antennas (resp. two transmit and two receive antennas). As space-time coding does not require any form of interleaving, the proposed system is attractive for delay-sensitive applications.

BLUETOOTH—The universal radio interface for ad hoc, wireless connectivity

Abstract: that is small enough to fit inside any electronic device or machine, that provides local connectivity, and that creates a (worldwide) micro-scale web. What applications might you use it in? In 1994, Ericsson Mobile Communications AB in Lund, Sweden, initiated a study to investigate the feasibility of a low-power, low-cost radio interface between mobile phones and their accessories. The intention was to eliminate cables between phones and PC cards, wireless headsets, and so forth. The study was part of a larger project that investigated multi-communicators connected to the cellular network via cellular telephones. The last link in the connection between a communicator and the cellular network was a short-range radio link to the phone—thus, the link was called the multicommunicator link or MC link. As the MC link project progressed, it became clear that there was no limit to the kinds of application that could use a short-range radio link. Cheap, short-range radios would make wireless communication between portable devices economically feasible. Current portable devices use infrared links (IrDA) to communicate with each other. Although infrared transceivers are inexpensive, they • have limited range (typically one to two meters); • are sensitive to direction and require direct line-of-sight; • can in principle only be used between two devices. By contrast, radios have much greater range, can propagate around objects and through various materials, and connect to many devices simultaneously. What is more, radio interfaces do not require user interaction. In the beginning of 1997, when designers had already begun work on an MC link

Global state routing: a new routing scheme for ad-hoc wireless networks

Abstract: In an ad-hoc environment with no wired communication infrastructure, it is necessary that mobile hosts operate as routers in order to maintain the information about connectivity. However with the presence of high mobility and low signal/interference ratio (SIR), traditional routing schemes for wired networks are not appropriate, as they either lack the ability to quickly reflect the changing topology, or may cause excessive overhead, which degrades network performance. Considering these restrictions, we propose a new scheme especially designed for routing in an ad-hoc wireless environments. We call this scheme "global state routing" (GSR), where nodes exchange vectors of link states among their neighbors during routing information exchange. Based on the link state vectors, nodes maintain a global knowledge of the network topology and optimize their routing decisions locally. The performance of the algorithm, studied in this paper through a series of simulations, reveals that this scheme provides a better solution than existing approaches in a truly mobile, ad-hoc environment.

IEEE 802.11-saturation throughput analysis

Abstract: To satisfy the emerging need of wireless data communications, the IEEE is currently standardizing the 802.11 protocol for wireless local area networks. This standard adopts a CSMA/CA medium access control protocol with exponential backoff. We present a simple analytical model to compute the saturation throughput performance in the presence of a finite number of terminals and in the assumption of ideal channel conditions. The model applies to both basic and request-to-send/clear-to-send (RTS/CTS) access mechanisms. Comparison with simulation results shows that the model is extremely accurate in predicting the system throughput.

Location-triggered reminder for mobile user devices

Abstract: A mobile user device, such as a personal digital assistant (PDA 100 ), a wireless telephone, a car phone, or any other programmable device that the user generally has with him or her, is equipped with a global positioning system (GPS) receiver ( 101 ) and is programmable ( 102 ) by the user to alert the user to when he or she arrives with the device at a predetermined location ( 252 ), as well as to disclose ( 101 ) to the user whatever information ( 263 ) the user chose to associate with that location (e.g., a “to-do” list). The user can program in the geographical coordinates ( 253 ) of locations and location names ( 252 ), and thereafter refer to the locations by name. The user can also program in a range ( 254 ) around each location, so that his or her arrival within that range will trigger the alert for the location.

Distributed satellite position system processing and application network

Abstract: A system and method for processing in a distributed manner satellite position system (SPS) information. In one example of the invention, a first mobile SPS receiver receives SPS signals from a plurality of SPS satellites and transmits a position information to a wireless cell based station which is coupled to a first communication network. The wireless cell based station is coupled to a first digital processing system which receives the position information from the wireless cell based station and calculates a location of the first mobile SPS receiver based upon the position information. The first digital processing transmits this location, usually without any presentation of this location on the first digital processing system, to a remotely located application digital processing system which presents the location to a user of the application digital processing system.

System for digital radio communication between a wireless LAN and a PBX

Abstract: A wireless local area network for digital radio communication between remote devices and a PBX telephone system, wherein the remote devices can access and use the voice message features in the PBX and the data bases on a host computer and servers. A wireless phone is provided for voice and data communication through the PBX or a CO telephone line with remote locations or the Internet using digital data packets and standard Internet Protocol. In a preferred embodiment of the invention, the remote device is a cash register comprising a bar code scanner and a phone. Radio communication between the register and a host computer is carried out over two channels, a first channel for data communication and a second channel for voice communication.

Cardiac simulation system having multiple stimulators for anti-arrhythmia therapy

Abstract: A medical system comprising a control device (referred to as a "planet") and a plurality of sensing and stimulating devices (referred to as "satellites") is disclosed. The satellites are relatively small devices that can be thoracoscopically attached to an exterior surface of the heart. The planet can be implanted if desired or, alternatively, externally retained. The planet is capable of wirelessly communicating (i.e., without a direct electrical connection) to each satellite. The planet individually commands each satellite to deliver pacing energy to the heart. Additionally, each satellite is capable of determining when a sense event has occurred at the site of that satellite and transmitting an encoded signal to the planet indicating that a sense event has occurred, along with an identifying code indicating to the planet which satellite detected the sense event. The planet processes the encoded signals received from the network of satellites, assigns time values to each satellite when that satellite detects a sense event, compares the time values to a template of normal values, and determines if an arrhythmia has occurred if the time values do not match the template. Further, the planet selects and implements an appropriate pacing protocol to terminate the arrhythmia. The satellites derive their needed power from signals received from the planet via the wireless communication path.

Adaptive frame length control for improving wireless link throughput, range, and energy efficiency

Abstract: Wireless network links are characterized by rapidly time varying channel conditions and battery energy limitations at the wireless mobile user nodes. Therefore static link control techniques that make sense in comparatively well behaved wired links do not necessarily apply to wireless links. New adaptive link layer control techniques are needed to provide robust and energy efficient operation even in the presence of orders of magnitude variations in bit error rates and other radio channel conditions. For example, research has advocated adaptive link layer techniques such as adaptive error control, channel state dependent protocols, and variable spreading gain. We explore dynamic sizing of the MAC layer frame, the atomic unit that is sent through the radio channel. A trade-off exists between the desire to reduce the header and physical layer overhead by making frames large, and the need to reduce frame error rates in the noisy channel by using small frame lengths. Clearly the optimum depends on the channel conditions. Through analysis supported by physical measurements with Lucent's WaveLAN radio we show that adaptive sizing of the MAC layer frame in the presence of varying channel noise indeed has a large impact on the user seen throughput (goodput). In addition, we show how that adaptive frame length control can be exploited to improve the energy efficiency for a desired level of goodput, and to extend the usable radio range with graceful throughput degradation. We describe the implementation of the adaptive MAC frame length control mechanism in combination with adaptive hybrid FEC/ARQ error control in a reconfigurable wireless link layer packet processing architecture for a low-power adaptive wireless multimedia node.

Wireless integrated network sensors: Low power systems on a chip

Abstract: Wireless Integrated Network Sensors (WINS) now provide a new monitoring and control capability for transportation, manufacturing, health care, environmental monitoring, and safety and security WINS combine sensing, signal processing, decision capability, and wireless networking capability in a compact, low power system WINS systems combine microsensor technology with low power sensor interface, signal processing, and RF communication circuits The need for low cost presents engineering challenges for implementation of these systems in conventional digital CMOS technology This paper describes micropower data converter, digital signal processing systems, and weak inversion CMOS RF circuits The digital signal processing system relies on a continuously operating spectrum analyzer Finally, the weak inversion CMOS RF systems are designed to exploit the properties of high-Q inductors to enable low power operation This paper reviews system architecture and low power circuits for WINS

IEEE 802.11 wireless LAN: capacity analysis and protocol enhancement

Abstract: In WLAN the medium access control (MAC) protocol is the main element for determining the efficiency in sharing the limited communication bandwidth of the wireless channel. This paper focuses on the efficiency of the IEEE 802.11 standard for wireless LANs. Specifically, we derive an analytical formula for the protocol capacity. From this analysis we found (i) the theoretical upper bound of the IEEE 802.11 protocol capacity; (ii) that the standard can operate very far from the theoretical limits depending on the network configuration; (iii) that an appropriate tuning of the backoff algorithm can drive the IEEE 802.11 protocol close to its theoretical limits. Hence we propose a distributed algorithm which enables each station to tune its backoff algorithm at run-time. The performances of the IEEE 802.11 protocol, enhanced with our algorithm, are investigated via simulation. The results indicate that the enhanced protocol is very close to the maximum theoretical efficiency.

Wireless integrated sensor network using multiple relayed communications

Abstract: Wireless integrated miniature sensing stations which can be organized into a communicating network allow sensitive detection and analysis of vibration, infrared radiation, sound, or other physical signals indicative of an intruder or condition to be monitored over a wide area. The sensing stations operate on low power and include a sensor or sensors, a digital signal processor, a microprocessor, and a wireless transceiver for communication. Network communication is facilitated by multiple relayed transmissions from station to station.

Comparative performance evaluation of routing protocols for mobile, ad hoc networks

Abstract: We evaluate several routing protocols for mobile, wireless, ad hoc networks via packet level simulations. The protocol suite includes routing protocols specifically designed for ad hoc routing, as well as more traditional protocols, such as link state and distance vector used for dynamic networks. Performance is evaluated with respect to fraction of packets delivered, end-to-end delay and routing load for a given traffic and mobility model. It is observed that the new generation of on-demand routing protocols use a much lower routing load. However the traditional link state and distance vector protocols provide, in general, better packet delivery and delay performance.

Method and apparatus for monitoring environmental conditions in a communication system

Abstract: A method and apparatus for monitoring and processing environmental conditions within a wireless communication system is accomplished when a subscriber (22), or group of subscribers, sense an environmental condition or conditions. Upon sensing the particular environmental condition (28) or conditions, the subscriber (or communication device) provides the information about the sensed environmental condition to infrastructure equipment over the wireless communication path. Once the infrastructure equipment receives the information about the sensed environmental condition, it processes it. The processing includes storing the information, averaging the information, predicting future environmental conditions, generating warning signals based on the levels of the environmental condition, and providing feedback to an individual communication device or a group of communication devices. Once information about the sensed environmental condition has been processed, the infrastructure equipment provides at least a selected portion of the processed data to a communication device, based on a subscription of the communication device.

Practical space-time radio method for CDMA communication capacity enhancement

Abstract: A practical way to enhance signal quality (carrier to interference. C/I) in both up and downlink of wireless point to multi-point CDMA service implements basic radio direction finding techniques to allow for optimal diversity combining in an antenna array employing large number of elements. This approach is facilitated through the use of very small bit counts arithmetic and capitalizing on finite alphabet signal structure (Walsh symbols, for example in IS-95 CDMA) or a known training sequence. Alternate implementations can use floating point data representations. The method facilitates ASIC implementation, thereby enabling distributed processing to achieve the required computation practicality. The method utilizes the uplink channel data to determine the downlink spatial structure (array beams) to enhance downlink C/I and hence, increase downlink capacity. The preferred embodiment is optimized to IS-95 , however, any signal that has either a finite alphabet or a training sequence built in can utilize the same idea. The use of the known signal structure facilitates simple array response vector determination and eliminates the necessity for covariance matrix calculation and analysis. Hence, this approach can be utilized for GSM and TDMA wireless air-interfaces as well.

Wireless, radio-frequency communications using a handheld computer

Abstract: A communications device provides a user with a sensory cue that informs the user of certain characteristics of a subsequent action that includes data communications. By informing the user of the data communication characteristics before the user initiates the data communication action, the invention appropriately sets user expectations regarding the data communication characteristics. For example, one embodiment of the invention is implemented in a portable communications device with a screen. For subsequent actions that include wireless communications, the portable communications device simultaneously displays a wireless link icon sensory cue next to a user interface graphic element. The user interface element is used to initiate the subsequent action. The user interface element can be an operating system object having an embedded link type icon. The wireless link icon informs the user that the subsequent action corresponding to the user interface element requires wireless communication and the expense and time associated therewith. A method, a system and an apparatus for indicating characteristics of a subsequent action to a user before the user begins the subsequent action are provided.

Wireless game control units

Abstract: A wireless control unit includes a controller having wireless transmitter circuitry for transmitting game information, and a console interface/adapter for converting one of the communication ports of the game console into a wireless receiver/transmitter. The console interface/adapter also includes an additional communication port so as to provide the user with access to the used communication port while the interface/adapter is operably disposed within the communication port of the game console.

Method and apparatus for providing electronic mail services during network unavailability

Abstract: Improved techniques for providing electronic mail services across a network are disclosed. A mail server and its clients communicate through a network. Although the mail server centrally manages the electronic mail services, the clients are able to themselves locally perform certain electronic mail services when the network is unavailable. Accordingly, clients seeking to perform electronic mail services no longer endure significant delays when the network is unavailable. The network can be unavailable for a variety of reasons, including: congestion, out of range, network failure, etc. The network can be wired or wireless. The invention is particularly well suited for networks having sporadic connectivity, high latencies or excessive traffic.

Singlecast interactive radio system

Abstract: A singlecast interactive radio system of the invention delivers digitized audio-based content to subscribers, upon their request, economically and with human voice quality. The system includes personal radio station servers, and a plurality of user terminals, and exploits one of the existing wireless communication networks as a transmission medium. A highly compressed voice-based information content is stored on data network servers, such as Internet World Wide Web servers. The personal radio station server stores multiple subscriber's profiles with topics of individual interest, assembles a content material from various Web sites according to the topics, and transmits the content to a subscriber's user terminal on subscriber's request over the wireless digital network. The user terminal restores voice-based material with at least AM-radio voice quality and transmission costs of such a material is very low in comparison to existing methods of voice communication, at least as a result of chosen compression algorithms. The user terminal optionally integrates, electrically and mechanically, a conventional radio and with a cellular phone equipment. The user can control system functions hands-free by issuing voice commands only. Such functions include, but are not limited to, cellular telephony voice dialing and control, secure network log-on based on voice identification, hands-free tuning to conventional radio-stations, changing audio playback level, and switching between functions. The user terminal also retrieves text material from the Internet or other data depositories, plays the material back as a computer-generated speech, digitizes a voice response from the user, and delivers the response to other e-mail addresses over related networks, including wired networks.

Dynamic bandwidth allocation to transmit a wireless protocol across a code division multiple access (cdma) radio link

Abstract: A technique for transmission of wireless signals across CDMA radio links. Bandwidth is allocated dynamically within a session to specific CDMA subscriber unit based upon data rate determinations. Specifically, a dynamic bandwidth allocation algorithm operates from limits calculated based upon available ports per subscriber, expected user bandwidth, and parallel user bandwidth versus throughput. Provisions for priority service, unbalanced forward and reverse spectrum utilization, voice prioritization, and band switching are also made.

Defibrillator with wireless communications

Abstract: A defibrillator having infrared communication capability is provided. The wireless communications capability is implemented using infrared light or RF communications and standardized communications protocols such as the IrDA protocol to allow for ready communication between defibrillators such as during handoffs of patient along the Chain of Survival. The wireless communications network also allows for communications between a defibrillator and a host computer such as a palmtop for incident report generation after each handoff. Another embodiment of the present invention provides for a defibrillator having an infrared mode switch to allow for restricted access to advanced cardiac life support (ACLS) features of the defibrillator. A further embodiment of the present invention provides for a defibrillator having a remote training mode that is implemented via wireless communications. Another embodiment of the present invention provides for a defibrillator test system that is implemented via wireless communications. A further embodiment of the present invention provides for a live ECG telemetry data link using the wireless communications system.

Communications network having adaptive network link optimization using wireless terrain awareness and method for use therein

Abstract: A communications network (10) having a plurality of wireless nodes (12-28) distributed within a region of interest makes routing decisions based on terrain information for the region of interest. A link quality determination unit (54) determines the quality of individual node-to-node links within the network (10), based on the location of the nodes (12-28) and the terrain about the nodes (12-28). A path selection unit 58 then determines an optimal path through the network 10 based on the link quality information. In one embodiment, communications corridors (102) are defined as preferred subpaths within a network for use in connecting remote nodes.

Prepayment method utilizing credit information stored in mobile terminals for accessing wireless telecommunication network

Abstract: A method of providing prepaid access to wireless telecommunication networks by utilizing a mechanism to store subscriber credit information within a mobile terminal is disclosed. The method is especially suitable for subscribers that roam into visiting networks that have the capability of accessing the credit information. In an embodiment of the invention, the method includes transmitting the previously stored subscriber credit information from the mobile terminal to a network's prepayment node during registration. The subscriber credit information, which may include a prepaid credit balance in dollars, is transmitted via the Over-the-Air-Teleservice (OATS) function as specified in the IS-136 standard. When a call is placed, the cost of the call, based on the current tariff rate, is calculated by the prepayment node and deducted from the initially received credit balance to determine an updated credit balance. The updated credit balance is transmitted via OATS to the mobile terminal for storage therein. The updated credit balance then becomes available to be retrieved by any compatible network that has the capability of utilizing the credit information.