Abstract:
Unitary transceiving units employ a multiple carrier, time-division-multiple-access (TDMA), time-division-duplex (TDD protocol to conduct concurrent wireless voice and data communications wherein a first transceiving base station unit tethered to a network interface wirelessly communicates to a second, mobile transceiving unit. The mobile transceiving unit wirelessly transmits and receives packetized voice and data information that is separated and routed to respective voice or data networks. The unitary mobile transceiving unit thus functions as a concurrent voice phone and data communications terminal/computer.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
   This application is related to commonly assigned and co-pending U.S. patent application Ser. No. 09/478,144 issued as U.S. Pat. No. 6,958,987 entitled “DECT-Like System and Method of Transceiving Information Over The Industrial-Scientific-Medical Spectrum” filed Jan. 5, 2000 and herein incorporated by reference. 
   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The invention relates generally to wireless communications and more specifically to a system and method of concurrent wireless voice and data communications. 
   2. Description of Related Art 
   The following background information is provided to aid in the understanding of the application of the present invention and is not meant to be limiting to the specific examples set forth herein. Reference is made to  FIG. 1  that depicts the prior art Digital Enhanced Cordless Telecommunications (DECT) standard protocol promulgated by the European Telecommunications Standards Institute (ESTI). The DECT standard defines a multiple carrier, time-division-multiple-access (TDMA), time-division-duplex (TDD) protocol with ten channels (carrier frequencies) between 1881.792 MHz and 1897.344 MHz spaced 1.728 MHz apart. Each of the ten channels supports a ten-millisecond frame comprised of twenty-four time slots. TDD is provided by allocating twelve of the twenty-four slots for base station to cordless handset communications and the other twelve slots for cordless handset to base station communications. Each time slot comprises 480 bits with a 32-bit preamble for synchronization, 388 bits for data and 60 bits for guard time. The 388 data bits are further divided into an A-field, a B-field and 4 parity bits for error detection. The A-field comprises an 8-bit header, 40 bits of control information and 16 cyclic redundancy check (CRC) bits while the B-field provides 320 bits of data. 
   For speech applications, analog signals are digitized and encoded using adaptive differential pulse code modulation (ADPCM). So-called “frequency hopping” is employed to avoid interference by periodically assigning a different one of the ten channel frequencies to each of the twenty-four time slots. A form of frequency shift keying known as Gaussian filtered, Minimum Shift Keying (GMSK) is used to modulate the transmitted signal to provide continuous phase transitions between two adjacent symbols. 
   By way of further background circa 1992, the Olivetti corporation released a DECT-based wireless local area network (LAN) data communication product known as “NET3”. Thereafter, the Siemens corporation introduced a voice communication DECT-based product known as the “Gigaset 900”. Subsequent to and on going, ETSI promulgated a range of Radio local loop Access Profiles (RAP) to designate DECT standard interoperability with products employing the so-called wireless local loop (WLL) a.k.a. radio local loop (RLL) such as ISDN and GSM networks. For example, DECT is being applied to cordless terminal mobility (CTM) in Italy wherein a cordless handset operates with both private and public DECT base stations. 
   By way of even further background, the IEEE promulgated in its 802.11 standard, inter alia, definitions for Frequency Hopping Spread Spectrum (FHSS) and Direct Sequence Spread Spectrum (DSSS) implementations of the physical layer of a WLAN. For FHSS in North America and most of Europe, IEEE 802.11 requires 79 channels in 1 MHz steps beginning at 2.402 GHz and ending at 2.480 GHz with a minimum frequency hop of 6 MHz.  FIG. 9  depicts the IEEE 802.11 protocol for packetizing information in a FHSS WLAN. One-hundred-twenty-eight (128) bits (a 96 bit preamble and 32 bit header) are sent to assist in synchronizing after a carrier hops from one frequency to the next. Payload data then follows in sizes ranging from 1 to 4095 bytes. The IEEE 802.11 standard however is devoid of any voice communication support. 
   Heretofore there has not been a product that supports both voice and data communications over a wireless transmission protocol such that voice conversations and data communications take place concurrently with unitary transceiving units for supporting both types of communications. 
   From the foregoing it can be seen that there is a need for a system and method that supports concurrent voice and data communications over wireless radio access technology such as, but not limited to DECT, employing unitary transceiving units. 
   SUMMARY OF THE INVENTION 
   To overcome the limitations of the prior art described above, and to overcome other limitations that will become apparent upon reading and understanding the present specification, the present invention discloses a system and method wherein unitary transceiving units employ a multiple carrier, time-division-multiple-access (TDMA), time-division-duplex (TDD) protocol to conduct concurrent wireless voice and data communications. A first transceiving base station unit is tethered to a voice communications network such as, but not limited to, a Public switched telephone network (PSTN), and to a data communications network and wirelessly communicates to a second, mobile transceiving unit. The mobile transceiving unit wirelessly transmits and receives packetized combined voice and data information to and from the base station unit. The base station unit receives and separates voice and data information and routes the respective information to either the voice or data network. The data network may manifest itself as, but is not limited to, a V.90, ISDN, DSL, or cable modem connections to the PSTN or Ethernet or Gigabit-Ethernet networks. The mobile transceiving unit receives, separates and processes voice and data information and routes the voice information to either a speaker/audio outlet and/or to the processing unit for processing and storage (e.g. digital answering machine) and the data information to the processing unit for applications such as, but not limited to, web browsing. 
   A feature of the present invention is that an unitary transceiving unit supports combined voice and data communications. 
   Another feature of the present invention is that concurrent voice and data communications enhances collaborative computing efforts wherein plural, remote users can conduct real-time audio dialog while viewing the same computing screen. 
   These and various other objects, features, and advantages of novelty which characterize the invention are pointed out with particularity in the claims annexed hereto and forming a part hereof. However, for a better understanding of the invention, its advantages, and the objects obtained by its use, reference should be made to the drawings which form a further part hereof, and to the accompanying descriptive matter, in which there is illustrated and described a specific example of a concurrent wireless voice and data communications system and method in accordance with the principles of the present invention. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  depicts a prior art diagram of the Digital Enhanced Cordless Telecommunications (DECT) standard protocol promulgated by the European Telecommunications Standards Institute (ESTI); 
       FIG. 2  depicts an illustrative but not limiting block diagram of a concurrent wireless voice and data communications system practiced in accordance with the principles of the present invention; 
       FIG. 3  depicts an illustrative but not limiting block diagram of a preferred Personal Access Device (PAD) practiced in accordance with the principles of the present invention; 
       FIG. 4  depicts a first exemplary but not limiting block diagram of a first preferred base station practiced in accordance with the principles of the present invention; 
       FIG. 5  depicts a second exemplary but not limiting block diagram of a second preferred base station practiced in accordance with the principles of the present invention; 
       FIG. 6  depicts an exemplary but not limiting block diagram of a preferred transceiver module practiced in accordance with the principles of the present invention; 
       FIG. 7  depicts the preferred protocol for a concurrent wireless voice and data communications system practiced in accordance with the principles of the present invention; 
       FIG. 8  depicts the preferred TDMA protocol for a concurrent wireless voice and data communications system practiced in accordance with the principles of the present invention, and, 
       FIG. 9  depicts a prior art IEEE 802.11 protocol for packetizing information in a frequency hopping spread spectrum wireless local area network. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENT 
   The detailed description of the preferred embodiment for the present invention is organized as follows: 
   1.0 Exemplary System 
   2.0 Exemplary Personal Access Device (PAD) 
   3.0 Exemplary Base Station 
   4.0 Exemplary Transceiver Module 
   5.0 PAD to Base Station Synchronization 
   6.0 PAD-to-PAD Communications 
   7.0 Conclusion 
   This organizational table and the corresponding headings used in this detailed description are provided for the convenience of reference only and are not intended to limit the scope of the present invention. It is to be understood that while the preferred embodiment is described herein below with respect to DECT and DECT-like wireless protocols, it has general applicability to any digital wireless communications technology. Certain terminology known to practitioners in the field of wireless communications is not discussed in detail in order not to obscure the disclosure. Moreover, in order not to obscure the disclosure with structural details which will be readily apparent to those skilled in the art having the benefit of the description herein, the structure, control and arrangement of conventional circuits have been illustrated in the drawings by readily understandable block representations showing and describing details that are pertinent to the present invention. Thus, the block diagram illustrations in the figures do not necessarily represent the physical arrangement of the exemplary system, but are primarily intended to illustrate the major structural components in a convenient functional grouping, wherein the present invention may be more readily understood. 
   Reference is now made to the accompanying drawings, which form a part hereof, and in which is shown by way of illustration specific embodiments in which the invention may be practiced. It is to be understood that other embodiments may be utilized and structural changes may be made without departing from the scope of the present invention. 
   1.0 Exemplary System 
   Reference is now made to  FIG. 2  that depicts an illustrative but not limiting block diagram of a concurrent wireless voice and data communications system practiced in accordance with the principles of the present invention. A Personal Access Device (PAD)  100  and base station  102  employ the present invention to provide RF connectivity therebetween. The PAD  100  preferably resides in a charging cradle  104  to keep rechargeable batteries (not shown) refreshed when not in use. When the PAD  100  is stationary and docked on the charging cradle  104 , commands may be entered with an optional keyboard  108  such as through the USB port  117 . When the PAD  100  is mobile, commands may be entered on the touch screen/touch keyboard (described in more detail herein below) of the PAD  100  with a detachable stylus  106  that resides within a storage cavity formed in case of the PAD  100 . The PAD  100  includes a microphone and speakers (described below) to support full duplex phone communications. 
   The base station  102  may manifest itself as an advanced set-top box  102   a  coupled to a television-like monitor (not shown), a stand-alone personal computer  102   b  or as a low cost stand alone device  102   c  with no display. The base station  102  is tethered to a voice network  109  that may manifest itself as but is not limited to a PSTN, and to a data network  110  that may manifest itself as but is not limited to, an Ethernet adapter, CATV, XDSL, ISDN or V.90 modems. 
   2.0 Exemplary Personal Access Device (PAD) 
   Reference is now made to  FIG. 3  that depicts an illustrative but not limiting block diagram of a preferred PAD  100  practiced in accordance with the principles of the present invention. A highly integrated processor  112  such as but not limited to, the Geode™ family of processors from National Semiconductor Corporation, Santa Clara, Calif., is coupled to DRAM  114  through an integrated DRAM controller (not shown) in the processor  112 . A so-called “south bridge” chipset  116  is coupled to the processor  112 , preferably through a PCI bus  113 . The south bridge chipset  116  preferably includes an integrated ISA bus controller coupled to an ISA bus  115 , a USB port  117  for supporting, inter alia, the keyboard  108  and FIFO buffers coupled to an audio CODEC  118 . A flash ROM  111  is connected to the ISA bus  115  for storing code (such as an operating system and application prograrns) that is shadowed into DRAM  114  for execution by processor  112 . The audio codec  118  converts digital signals to analog signals and drives speakers  121  and receives and converts analog signals from a monaural microphone  123  to digital signals for processing by processor  112 . The display  120 , which preferably is a DSTN or TFT LCD, is refreshed by a display adapter (not shown) that is integrated into either the processor  112  or chipset  116 . The display  120  includes an overlaid programmable touch control panel  101  controlled by microcontroller  127  for use with removable stylus  106 . The microcontroller  127  also provides charge profiling for rechargeable battery  129 . The transceiver module  125  (discussed in more detail hereinbelow) is preferably, although not exclusively, connected to the ISA bus  115  for providing a wireless link to the base station  102 . 
   3.0 Exemplary Base Station 
   Reference is now made to  FIG. 4  that depicts a block diagram of the first preferred base station  102  without the transceiver module  125  installed, practiced in accordance with the principles of the present invention. While the first exemplary embodiment of the base station  102  is depicted as having a V.90 modem  135 , those skilled in the art will readily recognize with the aid of the present disclosure, other forms of data network interfaces including but not limited to, ISDN, DSL and CATV modems and network adapters such as, but not limited to, Ethernet without departing from the scope of the present invention. The V.90 modem interface  135  of the base station  102  is coupled to a Public switched telephone network (PSTN) through RJ11 jack  130 . RJ11 jack  130  connects a first analog phone line through a first Digital Access Arrangement (DAA)  131  included within the V.90 modem  135 . A combined CODEC/hybrid circuit  136  separates transmitted signals from received signals from the PSTN and converts the received signals into digital form. The received digital signals are operated on by a digital signal processor (DSP)  138  that executes code out of flash ROM  140  and SRAM  142  and  144  to provide, inter alia, interface control, AT command processing, and processing functions needed to perform signal modulations. Through execution of the code, the DSP  138  provides a command line AT interpreter, error checking, re-transmission, compression and decompression functions as well as necessary signal modulation/demodulation, adaptive filtering and encoding/decoding required for a V.90 standard modem. 
   A second RJ11 jack  132  connects a second analog phone line from the PSTN to a second DAA  133  for voice reception/transmission. An optional third Rj11 jack  134  may be used to connect an external handset (not shown) to the base station  102 . Optional LED indicators  143  controlled by DSP  138  display status of device ready, data and voice transmission in progress. Optional page key  145  may be provided to signal the transceiver module  150  (depicted in  FIG. 5 ) through connector  149   a  to emit a page signal to the PAD  100 . A power on reset (POR) circuit  147  provides reset signals to circuitry on the base station  102  as well as through connector  149   a  to the transceiver module  125 , described in more detail herein below. 
   Reference is now made to  FIG. 5  that depicts a block diagram of a second preferred base station  102 ′ without the transceiver module  125  installed, practiced in accordance with the principles of the present invention. The second preferred base station  102 ′ is constructed similar to that of the first base station  102  except for the elimination of secondary DAA  133  and the addition of the relay  137 . In the second preferred version of the base station  102 ′, relay  137 , which is controlled via the baseband processor  180  in transceiver module  125 , switches the PSTN coupled through RJ11 jack  130  and DAA  131  to either the data network adapter (e.g. modem) or the ancillary analog voice channel (provided by the baseband processor  180  in transceiver module  125 ), all of which is discussed in more detail herein below. 
   Although while only one phone line is connected to the base station  102 ′, the user of a PAD  100  can utilize the data network (via modem) and still be made aware of an incoming call via the transceiver module  125  that provides call notification and caller ID to allow the user of the PAD  100  to switch from the data network to the voice network. For example, this may manifest itself through a pop-up window on the PAD  100  notifying a single phone line user of PAD  100  (who may be surfing the world-wide-web) of an incoming phone call thus permitting the user of PAD  100  to switch from surfing the web to answer the phone call. 
   4.0 Exemplary Transceiver Module 
   Reference is now made to  FIG. 6  that depicts by way of illustration an exemplary but not limiting block diagram of the preferred transceiver module  125  practiced in accordance with the principles of the present invention. The transceiver module  125  comprises an antenna  152  (multiple antennas for diversity), an RF sub-module  150  coupled to a baseband processor  180 , a flash ROM  182  and RAM  183  to store code for execution by the baseband processor  180  and a mating connector  149   b  for connecting to either the base station connector  149   a  or to the ISA bus  115  in the PAD  100 . 
   The RF sub-module  150  includes, inter alia, a band pass filter (BPF)  154  coupled to a transmit/receive switch  156 . Received data from the transmit/receive switch  156  is conditioned by a low noise amplifier (LNA)  158  and a BPF  160  prior to being sent to a mixer within single chip radio transceiver  162 . Transmitted data from the single chip radio transceiver  162  is passed through a LNA  164  and transmit power amplifier  166  prior to being sent to transmit/receive switch  156 . An exemplary but not limiting example of a single chip containing the BPFs  154  and  160 , LNAs  158  and  164 , transmit/receive switch  156  and power amplifier  166  is the AU2404T RF front-end integrated circuit from Alation Systems Inc. of Mountain View, Calif. Those skilled in the art, with the aid of the present disclosure, will recognize other forms and solutions for elements  154 ,  156 ,  158 ,  160 ,  164  and  166  without departing from the spirit and scope of the present invention. 
   The single chip radio transceiver  162  in combination with BPFs  168  and  170  and voltage controlled oscillator (VCO)  172  and loop filter  174  down convert (receive) or up convert (transmit) data to/from baseband processor  180 . The preferred although not exclusive embodiment for the single chip radio transceiver  162  is the LMX3162 transceiver from National Semiconductor Corporation of Santa Clara, Calif., described in the  National Analog and Interface Products Databook  (and accompanying CD-ROM), 1999, which is herein incorporated by reference. The RF sub-module  150  is available from ALPS Electric Co, Ltd. of Tokyo, Japan under the model numbers UGSA4-402A (without antenna diversity) and UGSA4-502A (with antenna diversity) for 2.4 GHz operation and under the model numbers UGSE2-402A (without antenna diversity) and UGSE2-502A (with antenna diversity) for 1.8 GHz (DECT) operation. 
   The baseband processor  180  preferably comprises a CODEC and at least one sub-processor that executes code stored in flash ROM  182  and RAM  183  to handle, inter alia, audio, signal and data processing for tone generation, echo canceling and to program slot and frame timing for the RF sub-module  150 . In general, the code executed by the baseband processor  180  in the transceiver module  125  is preferably layered in adherence with the Open Systems Interconnection (OSI) model, the details of which are known to one skilled in the art. The preferred although not exclusive embodiment for the baseband processor  180  is the SC14424 baseband processor from National Semiconductor Corporation of Santa Clara, Calif., described in detail in Appendix A hereto. 
   Reference is now made to  FIG. 7  that depicts the preferred protocol for a concurrent wireless voice and data communications system practiced in accordance with the principles of the present invention. The preferred protocol is a multiple carrier, Time-division-multiple-access (TDMA), Time-division-duplex (TDD) system. The preferred programmable, although not exclusive number of carrier frequencies is seventy-five ranging between 2401.122 MHz to 2479.813 MHz and spaced 1.063 MHz apart. Those skilled in the art having the benefit of the description herein will appreciate other numbers of carrier frequencies (e.g. ten), frequency spectrums (e.g. 1881.792 MHz to 1897.344 MHz) and spacings (e.g. 1.728 MHz apart) without departing from the scope the present invention. Each of the seventy-five channels supports a ten-millisecond frame preferably comprised of sixteen time slots. Those skilled in the art having the benefit of the description herein will appreciate other numbers of time slots without departing from the scope the present invention. Symmetrical TDD is provided by allocating half (i.e. eight of the sixteen slots) for base station to PAD communications and the other half (i.e. eight slots) for PAD to base station communications. Asymmetrical TDD is contemplated as well wherein base station to PAD communications consume more slots (e.g. twelve slots) than PAD to base station communications (i.e. four slots) or vice versa. Those skilled in the art having the benefit of the description herein will appreciate other asymmetric numbers of slot allocations for base station to PAD communications and vice versa without departing from the scope the present invention. 
   Each time slot preferably comprises a 32-bit preamble for synchronization, a 64 bit A-field for signaling and a B-field comprising 320 bits and 4 bits for CRC. Each of the sixteen time slots receives/transmits on one of the seventy-five carrier channels that preferably changes in a pseudo-random fashion, to one of the other seventy-four carrier channels after two consecutive frames thus providing fifty (50) hops/second. Those skilled in the art having the benefit of the description herein will appreciate other number of frequency carriers, hopping patterns and frequency hop periods without departing from the scope the present invention. 
   Reference is now made to  FIG. 8  that depicts the preferred TDMA protocol in more detail. In the preferred embodiment, symmetric TDMA (with respect to both voice/data and base station/PAD communications) is provided by allocating time slots  1 ,  2 ,  3  and  9 ,  10 ,  11  for data communication between base station and PAD and PAD and base station, respectively, and time slots  4 ,  5 ,  6  and  12 ,  13 ,  14  for voice communication between base station and PAD and PAD and base station, respectively. Time slots  7  and  15  are reserved, time slot  8  is allocated to program the transmit carrier frequency in the single chip radio transceiver  162  and slot  16  is allocated to program the receive carrier frequency. 
   Asymmetrical TDMA is contemplated as well wherein data communications consume more slots (e.g. twelve slots) than voice communications (i.e. four slots) or vice versa. As mentioned above, asymmetry with respect to base station/PAD communications is contemplated and it is further contemplated that asymmetric base station/PAD communications may be used in combination with asymmetric data/voice TDMA. Those skilled in the art having the benefit of the description herein will appreciate other asymmetric numbers of slot allocations for base station/PAD communications and/or data/voice communications without departing from the scope the present invention. 
   To achieve frequency hopping, the transmit and receive carrier frequencies are changed by the baseband processor  180  reprogramming a phase locked loop (PLL) in the single chip radio transceiver  162 . The transmit and receive carrier frequencies are changed by the baseband processor  180  in a pseudo-random fashion, to one of the other seventy-four carrier channels after two consecutive frames thus providing fifty (50) hops/second. 
   Referring to  FIG. 8   b , a time slot dedicated to data allocates 80 bits in the B field to a Forward Error Correction Code (FECC). The remaining 240 bits are payload data for processing by the PAD  100 . A time slot dedicated to voice allocates the entire 320 bits in the B field to voice information since voice is tolerant to dropouts in bit patterns. 
   So-called “multi-slot” operation (e.g. double slot) is further contemplated wherein adjacent slots share a single set of sync, signaling, CRC bits and optionally, FECC bits. In a single data slot, the sync, signaling, CRC and FECC bits consume  180  out of the 420 bits allocated to a slot. By way of illustration and not of limitation, a double data slot shares one 32-bit preamble for synchronization, one 64 bit A-field for signaling, one set of 80 FECC bits and one set of four CRC bits, thus providing 660 payload data bits over two slots instead of the standard 480 bits—a 37.5% increase in bandwidth. Those skilled in the art having the benefit of the description herein will appreciate other multi-slot configurations (e.g. quad slots) and allocation of overhead bits without departing from the scope the present invention. 
   5.0 PAD to Base Station Synchronization 
   On power up, the baseband processor  180  in the transceiver module  125  of the PAD  100  executes code to set the received carrier frequency to a reference channel and to scan for incoming data during a time period of two frames (e.g. 20 milliseconds). If an A-Field with a correct CRC is detected, the baseband processor  180  continues to sample and decode A-Fields every frame (e.g. 10 milliseconds) for the expected ID of the base station  102 . If a timeout occurs, the baseband processor  180  code restarts with the next carrier frequency channel. If the correct ID for the base station  102  is received, the A-field decoding continues until the current slot number, frame number, multi-frame number, and carrier channel in which the base station  102  is scanning are received. The base band processor  180  updates its corresponding internal variables and enters into a locked state when this information is received. 
   The baseband processor  180  in the transceiver module  125  of the base station  102  executes code to fix the transmit carrier frequency to a reference channel until the PAD  100  synchronizes. Thereafter, the baseband processor  180  executes code to change the transmit carrier frequency in the transceiver module  125  of the base station  102  every two frames (e.g. 20 milliseconds) in a pseudo-random sequence so long as correct A-Fields are found in two consecutive frames. The PAD  100  continues to receive A-Fields until the expected ID of the base station  102  is received or a timeout occurs. If a timeout occurs, the process is restarted with the reference channel frequency. 
   6.0 PAD-to-PAD Communications 
   PAD-to-PAD communications is further contemplated wherein multiple PADs communicate with one another through a common base station  102 . By way of illustration and not of limitation, a second PAD  100 ′ is added to  FIG. 2  wherein PADs  100  and  100 ′ communicate with one another via the base station  102 . Each PAD  100  and base station have a unique ID associated with it that can be embedded in the A-field (64 bits of signaling) of the intended target. The baseband processor  180  in the transceiving module  125  of the base station  102  detects whether the received ID in the A-field is intended for the base station  102 . If so, the voice/data information associated with that A-field is processed and routed to the respective voice/data network tethered to the base station  102 . If not, the base station  102  relays the voice/data information associated with that A-field onto the intended PAD  100 ′. 
   7.0 Conclusion 
   Although the Detailed Description of the invention has been directed to certain exemplary embodiments, various modifications of these embodiments, as well as alternative embodiments, will be suggested to those skilled in the art. The invention encompasses any modifications or alternative embodiments that fall within the scope of the Claims.