Abstract:
A multi-mode mobile station comprising 1) reconfigurable transceiver circuitry for communicating with wireless networks operating under different air interface standards; 2) a memory for storing at least a download configuration file and a home configuration file; and 3) a main controller for configuring the reconfigurable transceiver circuitry to operate according to a home network wireless standard using home configuration data retrieved from the home configuration file. If the main controller determines that a network operating according to the home network wireless standard cannot be found, the main controller is further capable of configuring the reconfigurable transceiver circuitry to operate according to a download channel wireless standard using download configuration data retrieved from the download configuration file. The main controller then establishes a download channel with a local roaming wireless network and downloads a roaming network configuration file from the roaming wireless network over the download channel.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     The present invention is related to that disclosed in U.S. Provisional Patent Application Ser. No. 60/551,687, filed Mar. 10, 2004, entitled “Method for Remotely Modifying Reconfigurable Hardware for Software Defined Radio Signal Processing”. U.S. Provisional Patent Application Ser. No. 60/551,687 is assigned to the assignee of the present application. The subject matter disclosed in U.S. Provisional Patent Application Ser. No. 60/551,687 is hereby incorporated by reference into the present disclosure as if fully set forth herein. The present invention hereby claims priority under 35 U.S.C. §119(e) to U.S. Provisional Patent Application Ser. No. 60/551,687.  
     
    
     TECHNICAL FIELD OF THE INVENTION  
       [0002]     The present invention relates generally to wireless networks and, more specifically, to a multi-mode, reconfigurable digital transceiver for use in a multi-mode mobile station that communicates with wireless networks operating under different standards.  
       BACKGROUND OF THE INVENTION  
       [0003]     Recent years have seen the deployment of a variety of different access standards for use in wireless networks (e.g., GSM, CDMA, WCDMA, IEEE-801.16, etc.). However, the proliferation of wireless access standards has proven to be inconvenient and challenging for the manufacturers of wireless mobile stations (or terminal), such as cell phones, PDA devices, wireless laptops, and the like. End-user expectations of a ubiquitous network cannot be met with mobile stations that support only a subset of the possible standards.  
         [0004]     In response, wireless mobile stations are transitioning to software-defined radio (SDR) architectures to provide common hardware platforms for multiple air interface technologies. The continual improvement of semiconductor process technology has enabled an increasingly greater percentage of the signal processing functions in a mobile station (or wireless terminal) to be performed by reconfigurable hardware. The reconfigurable hardware may take one of several forms, including fixed functional blocks with customizable parameters and flexible interconnects. The reconfigurable hardware may be implemented, for example, in a field-programmable gate array (FPGA).  
         [0005]     While fully configurable devices such as field programmable gate arrays currently have issues related to power and cost, the evolution in process and architecture technology is likely to overcome these limitations in time. However, within a software-refined radio (SDR) system, it is expensive and wasteful to store in memory all of the possible configuration files that the mobile station is likely to need.  
         [0006]     To avoid such large memories, a user may transport the mobile station to a wireless service center and have the mobile station configuration software installed through cabling when needed. As users travel from one geographical region to another region that is served by a different wireless standard, a similar paradigm of reconfiguration for hardware is frustrating to the user and costly to wireless service providers.  
         [0007]     Therefore, there is a need in the art for a multi-mode mobile station that is capable of being reconfigured to operate according to a variety of air interface standards. More particularly, there is a need for a multi-mode mobile station that does not require a large memory of storing a large number of configuration files.  
       SUMMARY OF THE INVENTION  
       [0008]     The present invention provides a multi-mode mobile station capable of being remotely configured to communicate in diverse wireless networks operating under different air interface standards (e.g., CDMA, WCDMA, GSM, etc.). The present invention also provides a method of remotely delivering and verifying SDR configuration files and automatically executing a reconfiguration of the reconfigurable hardware of the multi-mode mobile station. The multi-mode mobile station receives its signal processing configuration from a centralized controller (i.e., a server) when needed. This eliminates the need for the mobile station to store and maintain the multiple radio configurations to which it may be set, but still allows the mobile station to support the many standards required by user demands. Advantageously, a mobile station according to the principles of the present invention may be reconfigured remotely with little or no user or service provider intervention.  
         [0009]     To address the above-discussed deficiencies of the prior art, it is a primary object of the present invention to provide a multi-mode mobile station. According to an advantageous embodiment of the present invention, the multi-mode mobile station comprises: 1) reconfigurable transceiver circuitry capable of communicating with wireless networks operating under different air interface standards; 2) a memory for storing at least a download configuration file and a home configuration file; and 3) a main controller capable of configuring the reconfigurable transceiver circuitry to operate according to a home network wireless standard using home configuration data retrieved from the home configuration file. The main controller is further capable of determining that a network operating according to the home network wireless standard cannot be found. The main controller, in response to that determination, is further capable of configuring the reconfigurable transceiver circuitry to operate according to a download channel wireless standard using download configuration data retrieved from the download configuration file.  
         [0010]     According to one embodiment of the present invention, the main controller is capable of validating the download configuration data.  
         [0011]     According to another embodiment of the present invention, the main controller is further capable of establishing a download channel with a roaming wireless network capable of operating according to the download channel wireless standard.  
         [0012]     According to still another embodiment of the present invention, the main controller is further capable of downloading a roaming network configuration file over the download channel from the roaming wireless network.  
         [0013]     According to another embodiment of the present invention, the main controller is further capable of configuring the reconfigurable transceiver circuitry to operate according to a roaming wireless standard using roaming configuration data retrieved from the downloaded roaming network configuration file.  
         [0014]     According to a further embodiment of the present invention, the main controller is capable of validating the roaming configuration data.  
         [0015]     According to a still further embodiment of the present invention, the download channel wireless standard operates in unlicensed radio frequency spectrum.  
         [0016]     Before undertaking the DETAILED DESCRIPTION OF THE INVENTION below, it may be advantageous to set forth definitions of certain words and phrases used throughout this patent document: the terms “include” and “comprise,” as well as derivatives thereof, mean inclusion without limitation; the term “or,” is inclusive, meaning and/or; the phrases “associated with” and “associated therewith,” as well as derivatives thereof, may mean to include, be included within, interconnect with, contain, be contained within, connect to or with, couple to or with, be communicable with, cooperate with, interleave, juxtapose, be proximate to, be bound to or with, have, have a property of, or the like; and the term “controller” means any device, system or part thereof that controls at least one operation, such a device may be implemented in hardware, firmware or software, or some combination of at least two of the same. It should be noted that the functionality associated with any particular controller may be centralized or distributed, whether locally or remotely. Definitions for certain words and phrases are provided throughout this patent document, those of ordinary skill in the art should understand that in many, if not most instances, such definitions apply to prior, as well as future uses of such defined words and phrases.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0017]     For a more complete understanding of the present invention and its advantages, reference is now made to the following description taken in conjunction with the accompanying drawings, in which like reference numerals represent like parts:  
         [0018]      FIG. 1  illustrates a wireless network in which a multi-mode mobile station may be remotely configured to communicate with base stations operating under different air interface standards according to the principles of the present invention;  
         [0019]      FIG. 2  is a high-level block diagram illustrating a multi-mode mobile station according to an exemplary embodiment of the present invention; and  
         [0020]      FIGS. 3A and 3B  illustrate in greater detail selected portions of the reconfigurable signal processing block in the multi-mode mobile station in  FIG. 2  according to a first embodiment of the present invention;  
         [0021]      FIGS. 4A and 4B  illustrate in greater detail selected portions of the reconfigurable signal processing block in the multi-mode mobile station in  FIG. 2  according to a second embodiment of the present invention;  
         [0022]      FIGS. 5A and 5B  illustrate in greater detail selected portions of the reconfigurable signal processing block in the multi-mode mobile station in  FIG. 2  according to a third embodiment of the present invention;  
         [0023]      FIGS. 6A and 6B  illustrate in greater detail selected portions of the reconfigurable signal processing block in the multi-mode mobile station in  FIG. 2  according to a first embodiment of the present invention;  
         [0024]      FIG. 7  illustrates exemplary configuration files in the memory of the multi-mode mobile station in  FIG. 2 ; and  
         [0025]      FIG. 8  is flow diagram illustrating the remote configuration of the multi-mode mobile station according to the principles of the present invention.  
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0026]      FIGS. 1 through 8 , discussed below, and the various embodiments used to describe the principles of the present invention in this patent document are by way of illustration only and should not be construed in any way to limit the scope of the invention. Those skilled in the art will understand that the principles of the present invention may be implemented in any suitably arranged wireless mobile station.  
         [0027]      FIG. 1  illustrates wireless network  100 , in which multi-mode mobile station (MS)  111  may be remotely configured to communicate with base stations  101  and  102  operating under different air interface standards (or wireless network standards) according to the principles of the present invention. In  FIG. 1 , it is assumed multi-mode MS  111  is roaming in wireless network  100 . Multi-mode MS  111  normally operates in a home network (not shown) under a first air interface standard (or a “home” network wireless standard). In this example, it is assumed that multi-mode MS  111  operates under the CDMA standard in its home network. In its home network, multi-mode MS  111  uses a home configuration file to set-up the re-configurable hardware within multi-mode MS  111  to communicate under the CDMA standard with its home network.  
         [0028]     However, when multi-mode MS  111  enters wireless network  100 , multi-mode MS  111  is roaming and cannot use its home configuration file. In this example, it is assumed that wireless network  100  normally operates under a second air interface standard (or a “roaming” network wireless standard) that is different than the first air interface standard in the home network of multi-mode MS  111 . In particular, it shall be assumed that wireless network  100  operates under the GSM standard.  
         [0029]     However, it is further assumed that at least some of the base stations (e.g., BS  101 ) of wireless network  100  are also capable of communicating with mobile stations using a third air interface standard (or a “download channel” wireless standard). In particular, it shall be assumed that BS  101  of wireless network  100  is also capable of operating under the IEEE-802.11b standard or a similar unlicensed standard. The IEEE-802.11b standard is a common technology that is well-known and low cost. Advantageously, since the IEEE-802.11b standard operates in unlicensed radio frequency (RF) spectrum, the service provider operating wireless network  100  can download hardware configurations to multi-mode MS  111  without using the expensive, licensed spectrum of the GSM standard.  
         [0030]     In order to communicate with wireless network  100 , multi-mode MS  111  must obtain a roaming configuration file that can be used to reconfigure multi-mode MS  111  to communicate with wireless network  100  according to the GSM standard. According to the principles of the present invention, multi-mode MS  111  accomplishes this by communicating with BS  101  of wireless network using the unlicensed download channel wireless standard, in this case the IEEE-802.11b standard. Multi-mode MS  111  accesses a central server via BS  101  using the IEEE-802.11b channel(s) and then downloads a roaming configuration file. Once downloaded, the roaming configuration file is used to reconfigure multi-mode MS  111  so that multi-mode MS  111  is able to communicate under the GSM standard with any base station of wireless network  100 .  
         [0031]     The present invention is not limited to use with truly mobile devices. The present invention also encompasses other types of wireless access terminals, including fixed wireless terminals. For the sake of simplicity, only mobile stations are shown and discussed hereafter. However, it should be understood that the use of the term “mobile station” in the claims and in the description below is intended to encompass both truly mobile devices (e.g., cell phones, wireless laptops) and a stationary wireless terminal (e.g., a machine monitor with wireless capability) that may be moved and then turned on (or activated) for the first time in a new area that is covered by a wireless network that uses a different air interface standard than the wireless network in which the stationary wireless terminal previously operated.  
         [0032]      FIG. 2  is a high-level block diagram illustrating multi-mode mobile station (MS)  111  according to an exemplary embodiment of the present invention. Multi-mode MS  111  comprises antenna  205 , duplexer  210 , transmit (TX) radio-frequency (RF) block  215 , receive (RX) radio-frequency (RF) block  220 , reconfigurable signal processing block  225 , reconfigurable modem  230 , main controller  235 , non-volatile (i.e., Flash) memory  240 , ENET/USB interface  245 , keypad  250  and display  255 . According to an exemplary embodiment of the present invention, modem  230  may be implemented by software-defined radio SSDR) device that is reconfigured by means of a new software load. Moreover, main controller  235  may be implemented by means of a general-purpose processor that executes a control program (not shown) stored in memory  240 .  
         [0033]     According to the principles of the present invention, reconfigurable signal processing block  225  is capable of operating under multiple air interface standards through the use of configuration data retrieved from configuration files stored in memory  240 . In an exemplary embodiment of the present invention, reconfigurable signal processing block  225  may be implemented by a field-programmable gate array (FPGA). Alternatively, an application-specific integrated circuit (ASIC) may be used.  
         [0034]     Main controller  235  controls the overall operation of multi-mode MS  111 . Main controller  235  is capable of executing end-user applications stored in memory  240 , such as web-browser applications, e-mail applications, voice data, and the like. Main controller  235  receives user input from keypad  250  and displays graphics and data on display  255 . If required, main controller  235  may communicate over a wireline with external devices via ENET/USB interface  245 . This may include downloading configuration files into memory  240  using ENET/USB interface  245 .  
         [0035]     In the forward channel (or downlink), incoming RF signals received by antenna  205  are transferred by duplexer  210  to receive RF block  220 . Receive RF block  220  down-converts the received RF signal to produce an intermediate frequency (IF) signal. Reconfigurable signal processing block  225  then down-converts the IF signal according to the selected air interface standard to produce a baseband signal. Modem  230  then demodulates the baseband signal to produce the user data (including voice data) for the end-user application.  
         [0036]     In the reverse channel (or uplink), modem  230  modulates outgoing user data to produce a baseband signal. Reconfigurable signal processing block  225  then up-converts the baseband signal according to the selected air interface standard to produce an outgoing intermediate frequency (IF) signal. Transmit RF block  215  then up-converts the outgoing IF signal to produce an outgoing RF signal. Duplexer  210  then directs the outgoing RF signal to antenna  205 .  
         [0037]      FIGS. 3-6  below illustrate exemplary configurations of reconfigurable signal processing block  225  according to several common air interface standards. These common air interface standards include wideband WCDMA, CDMA, IEEE-802.11b, and GSM.  
         [0038]      FIGS. 3A and 3B  illustrate in greater detail selected portions of reconfigurable signal processing block  225  in multi-mode mobile station (MS)  111  according to a first embodiment of the present invention.  FIG. 3A  illustrates selected portions of the receive path of reconfigurable signal processing block  225  during WCDMA operation.  FIG. 3B  illustrates selected portions of the transmit path of reconfigurable signal processing block  225  during WCDMA operation.  
         [0039]     The receive path of reconfigurable signal processing block  225  comprises analog-to-digital converter (ADC)  305 , in-phase (I) mixer  310 , quadrature (Q) mixer  315 , numerically-controlled oscillator (NCO)  320 , cascaded integrator/comb (CIC) filter stage  325 , finite impulse response (FIR 1 ) filter stage  330 , finite impulse response (FIR 2 ) filter stage  335 , interpolation half-band filter  340 , and resampler  345 . The receive path of reconfigurable signal processing block  225  in  FIG. 3A  receives the IF signal, A(in), from receive RF block  220  and produces the digital baseband I and Q signals.  
         [0040]     The transmit path of reconfigurable signal processing block  225  comprises finite impulse response (FIR 2 ) filter stage  350  and finite impulse response (FIR 1 ) filter stage  360 . The transmit path of reconfigurable signal processing block  225  in  FIG. 3B  receives digital baseband I and Q signals from modem  230  and produces digital filtered I and Q signals according to the channel filter specification of the standard. The WCDMA operation of both the receive path and the transmit path of reconfigurable signal processing block  225  is controlled by configuration data retrieved from memory  240  that configures the hardware of reconfigurable signal processing block  225 .  
         [0041]      FIGS. 4A and 4B  illustrate in greater detail selected portions of reconfigurable signal processing block  225  in multi-mode mobile station (MS)  111  according to a second embodiment of the present invention.  FIG. 4A  illustrates selected portions of the receive path of reconfigurable signal processing block  225  during CDMA operation.  FIG. 4B  illustrates selected portions of the transmit path of reconfigurable signal processing block  225  during CDMA operation.  
         [0042]     The receive path of reconfigurable signal processing block  225  comprises analog-to-digital converter (ADC)  405 , in-phase (I) mixer  410 , quadrature (Q) mixer  415 , numerically-controlled oscillator (NCO)  420 , cascaded integrator/comb (CIC) filter stage  425 , finite impulse response (FIR 1 ) filter stage  430 , finite impulse response (FIR 2 ) filter stage  435 , and interpolation half-band filter  440 . The receive path of reconfigurable signal processing block  225  in  FIG. 4A  receives the IF signal, A(in), from receive RF block  220  and produces the digital baseband I and Q signals.  
         [0043]     The transmit path of reconfigurable signal processing block  225  comprises finite impulse response (FIR 2 ) filter stage  450  and finite impulse response (FIR 1 ) filter stage  460 . The transmit path of reconfigurable signal processing block  225  in  FIG. 4B  receives digital baseband I and Q signals from modem  230  and produces digital filtered I and Q signals according to the channel filter specification of the standard. The CDMA operation of both the receive path and the transmit path of reconfigurable signal processing block  225  is controlled by configuration data retrieved from memory  240  that configures the hardware of reconfigurable signal processing block  225 .  
         [0044]      FIGS. 5A and 5B  illustrate in greater detail selected portions of reconfigurable signal processing block  225  in multi-mode mobile station (MS)  111  according to a third embodiment of the present invention.  FIG. 5A  illustrates selected portions of the receive path of reconfigurable signal processing block  225  during IEEE-802.11b operation.  FIG. 5B  illustrates selected portions of the transmit path of reconfigurable signal processing block  225  during IEEE-802.11b operation.  
         [0045]     The receive path of reconfigurable signal processing block  225  comprises analog-to-digital converter (ADC)  505 , in-phase (I) mixer  510 , quadrature (Q) mixer  515 , numerically-controlled oscillator (NCO)  520 , finite impulse response (FIR 1 ) filter stage  525 , finite impulse response (FIR 2 ) filter stage  530 , and resampler  535 . The receive path of reconfigurable signal processing block  225  in  FIG. 5A  receives the IF signal, A(in), from receive RF block  220  and produces the digital baseband I and Q signals.  
         [0046]     The transmit path of reconfigurable signal processing block  225  comprises finite impulse response (FIR 1 ) filter stage  550 . The transmit path of reconfigurable signal processing block  225  in  FIG. 5B  receives digital baseband I and Q signals from modem  230  and produces digital filtered I and Q signals according to the channel filter specification of the standard. The IEEE-802.11b operation of both the receive path and the transmit path of reconfigurable signal processing block  225  is controlled by configuration data retrieved from memory  240  that configures the hardware of reconfigurable signal processing block  225 .  
         [0047]      FIGS. 6A and 6B  illustrate in greater detail selected portions of reconfigurable signal processing block  225  in multi-mode mobile station (MS)  111  according to a first embodiment of the present invention.  FIG. 6A  illustrates selected portions of the receive path of reconfigurable signal processing block  225  during GSM operation.  FIG. 6B  illustrates selected portions of the transmit path of reconfigurable signal processing block  225  during GSM operation.  
         [0048]     The receive path of reconfigurable signal processing block  225  comprises analog-to-digital converter (ADC)  605 , in-phase (I) mixer  610 , quadrature (Q) mixer  615 , numerically-controlled oscillator (NCO)  620 , cascaded integrator/comb (CIC) filter stage  625 , finite impulse response (FIR 1 ) filter stage  630 , finite impulse response (FIR 2 ) filter stage  635 , interpolation half-band filter  645 , and resampler  640 . The receive path of reconfigurable signal processing block  225  in  FIG. 6A  receives the IF signal, A(in), from receive RF block  220  and produces the digital baseband I and Q signals.  
         [0049]     The transmit path of reconfigurable signal processing block  225  comprises finite impulse response (FIR 1 ) filter stage  650 . The transmit path of reconfigurable signal processing block  225  in  FIG. 6B  receives digital baseband I and Q signals from modem  230  and produces filtered I and Q signals according to the channel filter specification of the standard. The GSM operation of both the receive path and the transmit path of reconfigurable signal processing block  225  is controlled by configuration data retrieved from memory  240  that configures the hardware of reconfigurable signal processing block  225 .  
         [0050]      FIG. 7  illustrates exemplary configuration files in memory  240  of multi-mode mobile station (MS)  111 . Memory  240  comprises download configuration file  710 , download configuration cyclic redundancy check (CRC) value  711 , home configuration file  720 , home configuration cyclic redundancy check (CRC) value  721 , roaming configuration file  730 , and roaming configuration cyclic redundancy check (CRC) value  731 . Download configuration CRC value  711  is used to verify the configuration data in download configuration file  710 . Home configuration CRC value  721  is used to verify the configuration data in home configuration file  720 . Finally, roaming configuration CRC value  731  is used to verify the configuration data in roaming configuration file  730 .  
         [0051]      FIG. 8  depicts flow diagram  800 , which illustrating the remote configuration of multi-mode mobile station (MS)  111  according to the principles of the present invention. Initially, multi-mode MS  111 , operating on its home configuration load (i.e., CDMA), roams into wireless network  100 , which is operating under the GSM standard in this example (process step  805 ). Multi-mode MS  111  determines that no CDMA network is available (process step  810 ). In response to that determination, multi-mode MS  111  validates and loads the configuration data from download configuration file  710 . Multi-mode MS  111  then reboots (process step  815 ).  
         [0052]     After reboot, multi-mode MS  111  searches for a download configuration channel (i.e., an IEEE-802.11b channel in this example) and accesses wireless network  100  (process step  820 ). Once an IEEE-802.11b download channel is established with wireless network  100 , multi-mode MS  111  downloads roaming configuration file  730  (i.e., a GSM configuration file) from a central server associated with wireless network  100  (process step  825 ). When the download operation is complete, multi-mode MS  111  validates and loads roaming configuration file  730 . Multi-mode MS  111  then reboots (process step  830 ). After reboot, multi-mode MS  111  searches for a roaming configuration channel (i.e., a GSM channel in this example) and accesses wireless network  100  (process step  835 ).  
         [0053]     It is worth noting that the operator of wireless network  100  does not need to deploy the download channel technology (i.e., IEEE-802.11b access points) with the same probability of coverage as the GSM base stations. Multi-mode mobile station  111  only needs a reasonable probability of encountering the download channel deployment within a reasonable period of time given a general travel profile. Thus, while all base stations of wireless network  100  communicate according to the roaming network wireless standard (i.e., GSM), only some of the base stations of wireless network  100  need to be capable of communicating according to the download channel wireless standard (i.e., IEEE-802.11b).  
         [0054]     After loading the roaming configuration file, multi-mode MS  111  contains a download configuration file (i.e., an IEEE-802.11b software load), a home configuration file (i.e., a CDMA software load), and a roaming configuration file (i.e., a GSM load). This enables multi-mode MS  111  to return rapidly to CDMA configuration when multi-mode MS  111  returns to its home network. It also provides for further configuration downloads if multi-mode MS  111  travels to a new region requiring a new air interface standard.  
         [0055]     Although the present invention has been described with an exemplary embodiment, various changes and modifications may be suggested to one skilled in the art. It is intended that the present invention encompass such changes and modifications as fall within the scope of the appended claims.