Abstract:
A multiband ultra wideband (UWB) communication is presented to implement multichannel shaped-pulses in parallel for indoor and outdoor UWB operations. The multiband UWB communication has a flexibility to transmit and receive a scalability data rate on the multichannel with lower power consumption.

Description:
BACKGROUND 
   This invention is generally relative to multiband ultra wideband (UWB) communications for short-distance wireless broadband communications. 
   U.S. Federal Communications Commission (FCC) released the revision of Part 15 of the Commission&#39;s rules regarding UWB transmission systems to permit the marketing and operation of certain types of new products incorporating an UWB technology on Apr. 22, 2002. With an appropriate technology, UWB devices are able to operate using spectrum occupied by existing radio service without causing interference. This allows scarce spectrum resources to be used more efficiently. The UWB technology offers significant benefits not only for Government and public safety but also for businesses and consumers under an unlicensed basis of operation spectrum. 
   In general, FCC is adapting unwanted emission limits for the UWB devices that are significantly more stringent than those imposed on other Part 15 devices. This is to say that FCC limits an outdoor use of UWB devices to handheld devices for the short-distance wireless broadband communications. For an indoor operation of UWB communications FCC provides a wide variety of the UWB devices, such as high-speed home and business networking devices under the Part 15 of the Commission&#39;s rules subject to certain frequency and power limitations. In short, the UWB devices must operate in the frequency band from 3.1 GHz to 10.6 GHz. In addition, the UWB devices should satisfy the Part 15.209 limit for the frequency band below 960 MHz and must meet the FCC&#39;s emission masks for the frequency band above 960 MHz. 
   For the indoor operation of UWB communications, Table 1 lists the FCC restrictions of the emission masks (dBm) along with the frequencies (GHz). 
   
     
       
             
             
             
           
         
             
                 
               TABLE 1 
             
             
                 
                 
             
             
                 
               Frequency (MHz) 
               EIRP (dBm) 
             
             
                 
                 
             
           
           
             
                 
                0-960 
               −41.3 
             
             
                 
                960-1610 
               −75.3 
             
             
                 
               1610-1990 
               −53.3 
             
             
                 
               1990-3100 
               −51.3 
             
             
                 
                3100-10600 
               −41.3 
             
             
                 
               Above 10600 
               −51.3 
             
             
                 
                 
             
           
        
       
     
   
   Outdoor handheld UWB devices are intended to operate in a peer-to-peer mode without restrictions on a location. The outdoor handheld UWB devices have extremely conservative out of band emission masks to address interference with other communication devices. Table 2 shows UWB emission masks for outdoor operations: 
   
     
       
             
             
             
           
         
             
                 
               TABLE 2 
             
             
                 
                 
             
             
                 
               Frequency (MHz) 
               EIRP (dBm) 
             
             
                 
                 
             
           
           
             
                 
                0-960 
               −41.3 
             
             
                 
                960-1610 
               −75.3 
             
             
                 
               1610-1900 
               −63.3 
             
             
                 
               1900-3100 
               −61.3 
             
             
                 
                3100-10600 
               −41.3 
             
             
                 
               Above 10600 
               −61.3 
             
             
                 
                 
             
           
        
       
     
   
   FCC defines an UWB device where the fractional frequency bandwidth is greater than 0.25 based on the formula as follows: 
                   FB   =     2   ⁢     (         f   H     -     f   L           f   H     +     f   L         )         ,           (   1   )               
where f H  is the upper frequency of the −10 dB emission point and f L  is the lower frequency of the −10 dB emission point. The center frequency of UWB transmission is defined as the average of the upper and lower −10 dB points as follows:
 
                   F   C     =           f   H     +     f   L       2     .             (   2   )               
In addition, a minimum frequency bandwidth of 500 MHz must be used for indoor and outdoor UWB communication devices regardless of the center frequency.
 
   Thus, the UWB communication devices must be designed to ensure that the indoor operations can only occur in an indoor environment according to the indoor emission masks as shown in Table 1. The outdoor operations must be according to the outdoor emission masks in Table 2. The UWB communication devices are used for short-range high-speed data transmissions suitable for wireless broadband access to networks. 
   The UWB communication devices, which are to be developed, are digital radio communications that belong to a wireless broadband communication technology fundamentally. The UWB communication devices transmit a sequence of very short electrical pulses, billionths of a second long, which exist not only on any particular frequency but also on all frequencies simultaneously. The UWB communication devices employ modulated pulses with less one nanosecond in duration. The modulated pulses can be assigned by a digital representation of “0” or “1” according to the transmitted and received pulse based on where the pulses are place in time. In other words, turning the modulated pulses for the wireless broadband communications lies in the timing of the pulses. Therefore, in order to recognize the information in a digital pulse sequence, an UWB receiver has to know the exact pulse sequence used by a transmitter. 
   Each of the modulated pulses can exist simultaneously across an extensive frequency band if the distributed energy of the modulated pulses at any given frequency exists in the noise floor. Because of the above reason, the UWB devices can co-exist with other communication devices with no discernable interference. Therefore, this opens vast new communications providing tremendous wireless bandwidth to ease the growing bandwidth crunch. 
   Transmitting the modulated pulses with a very-high data rate over the frequency ranges from 3.1 GHz to 10.6 GHz requires an analog-to-digital (A/D) converter with a very-high sampling rate F S  in order to implement the UWB receiver in a digital domain directly. Furthermore, due to the FCC emission limitations of the indoor and outdoor operations, transmitting the modulated pulses should be shaped in such a way that the transmitted pulses must not validate the FCC emission limitation. This leads to high requirements for designing a digital-to-analog (D/A) converter and a transmitter filter in an UWB transmitter. However, it is difficult to design the A/D and D/A converters with such a very high sampling rate for an UWB communication transceiver. In addition, the UWB communication transceiver does not have a flexibility and scalability to transmit and receive the modulated pulses if the UWB communication transceiver is designed to use the entire frequency band from 3.1 GHz to 10.6 GHz as one single-band operation. 
   The present invention uses a multiband with a multicarrier solution to form 11 multichannels for the UWB communication transceiver. Each multichannel has a frequency bandwidth of 650 MHz, which allows transmitting a data rate at 650 Msps. Shaped pulses that meet the FCC requirements of emission limitations for the indoor or outdoor operation can be transmitted on all of the multichannels at the same time. This is to say that the UWB communication transceiver is able to transmit a total of data rate up to 7.15 Gsps. As a result, the UWB communication transceiver can transmit a data rate with flexibility and scalability. Moreover, the sampling rate of the A/D and D/A converters can be reduced because of using a multiband approach to substitute a single wideband approach. In addition, the present invention is a single device of the UWB communication transceiver, which can be used to deal with a dual-mode indoor and outdoor operation. This leads to saving cost for the UWB communication transceiver. 
   Thus, there is a continuing need for the UWB communication transceiver employing a new dual-mode shaped pulse architecture based on a multiband and multicarrier solution for the indoor and outdoor operations. 
   SUMMARY 
   In accordance with one aspect, a multiband UWB communication transmitter may include an encoder coupled to an interleaver the interleaver coupled to a polyphase-based multichannel, the polyphase-based multichannel coupled to a shaped pulse generator, the shaped pulse generator coupled to a multichannel-based multicarrier modulator, the multichannel-based multicarrier modulator coupled to a power amplifier (PA), a clock control coupled to the polyphase-based multichannel, the shaped pulse generator, and the multichannel-based multicarrier modulator. 
   Other aspects are set forth in the accompanying detailed description and claims. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  shows a block diagram of a multiband UWB communication transceiver for indoor and outdoor operations according to one embodiment. 
       FIG. 2  is a block diagram of a multiband UWB communication transmitter for the indoor and outdoor operations according to some embodiments. 
       FIG. 3  is a detailed block diagram of a polyphase-based multichannel and multicarrier of the UWB communication transmitter according to some embodiments. 
       FIG. 4  is a binary phase-shift keying (BPSK) modulation relationship between a shaped pulse sequence and a binary symbol sequence according to some embodiments. 
       FIG. 5  is a two-block diagram of a polyphase-based serial-to-parallel (S/P) multichannel according to some embodiments. 
       FIG. 6  is a quadrature phase-shift keying (QPSK) modulation relationship between the shaped pulse sequence and the binary symbol sequence according to some embodiments. 
       FIG. 7  is shaped digital pulses for an indoor UWB communication transmitter according to some embodiments. 
       FIG. 8  is a frequency spectrum of the shaped digital pulses for the indoor UWB communication transmitter according to some embodiments. 
       FIG. 9  is the shaped digital pulses for an outdoor UWB communication transmitter according to some embodiments. 
       FIG. 10  is a frequency response of the shaped digital pulses for the outdoor UWB communication transmitter according to one embodiment. 
       FIG. 11  is a block diagram of two pulse memory banks according to some embodiments. 
       FIG. 12  is a frequency response of a multiband solution for the indoor UWB communication transmitter according to one embodiment. 
       FIG. 13  is a frequency response of the multiband solution for the outdoor UWB communication transmitter according to one embodiment. 
       FIG. 14  is a block diagram of a multiband UWB receiver for the indoor and outdoor operation according to some embodiments. 
       FIG. 15  is a detailed block diagram of a polyphase-based multichannel and multicarrier down converter for the multiband UWB receiver according to one embodiment. 
       FIG. 16  is a detailed block diagram of a polyphase-based parallel-to-serial (P/S) according one embodiment. 
   

   DETAILED DESCRIPTION 
   Some embodiments described herein are directed to a multiband UWB communication transceiver for the indoor and outdoor operations. The multiband UWB communication transceiver may be implemented in hardware, such as in an Application Specific Integrated Circuits (ASIC), digital signal processor, field programmable gate array (FPGA), software, and/or a combination of hardware and software. 
   A multiband UWB communication transceiver  100  for the indoor and outdoor operations is illustrated in  FIG. 1  in accordance with one embodiment of the present invention. The multiband UWB communication transceiver  100  includes a low noise amplifier (LNA) and power amplifier (PA) section  114  that receives and transmits multiband UWB signals from an antenna  112  and to an antenna  110 . The LNA and PA section  114  is coupled to a UWB multichannel-based multicarrier RF section  116 . The UWB multichannel-based multicarrier RF section  116  is connected to an analog and digital interface section of  118  that contains analog-to-digital (A/D) and digital-to-analog (D/A) converters. The analog and digital interface section  118  is coupled to an digital baseband processing section  120 , which performs polyphase multichannel digital transmission and receiver filtering, rake processing, shaped pulse generation, interleave/de-interleave, and code/de-code processing. The digital baseband processing section  120  has an interface with an UWB network interface section  122 , which is coupled to an UWB network  124 . In accordance with one embodiment of the present invention, the multiband UWB communication transceiver  100  is used for the indoor and outdoor operations. The multiband UWB communication transceiver  100  can transmit and receive speech, audio, images and video, and data information for indoor and outdoor wireless broadband communications. 
   The multiband UWB communication transceiver  100  has a flexibility to transmit and receive UWB signals by using one channel and/or up to 11 channels in parallel. Each channel of the UWB communication transceiver  100  has a frequency bandwidth of 650 MHz that can transmit a data rate of 650 Msps. As a result, the UWB communication transceiver  100  is able to transmit and receive the data rate up to 7.150 Gsps by using all of the channels in parallel. 
     FIG. 2  is the block diagram of a multiband UWB communication transmitter  200  for the indoor and outdoor operations according to some embodiments. The multiband UWB communication transmitter  200  receives user data bits  210  at a data rate of 3,575 Mbps. The user data bits  210  are passed through a ½-rate convolution encoder  212  that may produce a double data rate of 7.150 Msps by adding redundancy bits. A symbol data, which is an output sequence of the ½-rate convolution encoder  212 , is then interleaved by using an interleaver  214 . Thus, the output symbols of the interleaver  214  are formed into 11-multichannel by using a polyphase-based multichannel  216 . A symbol data rate of each channel is 650 Msps. The polyphase-based multichannel  216  is to perform a serial data into a parallel data by using a polyphase operation. The polyphase-based multichannel  216  is coupled to a shaped pulse generator  218  that generates the shaped digital pulses for the polyphase-based multichannel  216  based on an individual symbol. Each of the shaped digital pulses has a frequency bandwidth of 650 MHz at −10 dBm and −20 dBm for the indoor and outdoor operations, respectively. The output shaped digital pulses of the polyphase-based multichannel  216  are then modulated with multi-carrier frequencies by using a multichannel-based multi-carrier modulator  220 . A clock control  222  is used to control the polyphase-based multichannel  216 , the shaped pulse generator  218 , and the multichannel-based multicarrier modulator  220 . Thus, the output shaped digital pulses of the multichannel-based multi-carrier modulator  220  are passed a power amplifier (PA)  224  through an antenna into air. The entire subsystem section  226  is referred to as a polyphase multichannel-based multicarrier pulse generator. 
   Referring to  FIG. 3  is a detail block diagram of the polyphase multichannel-based multicarrier pulse generator  226  according to some embodiments. An input signal is assumed as x[n], where x[n] is an either “1” or “0” sequence for a serial-to-parallel (S/P) unit  310 , which is a polyphase structure downsampling by 11. The output of the S/P unit  310  contains 11 channels labeled from  311   a  to  311   k  in a parallel operation. Correspondingly, the output signals of the S/P unit  310  are x[11n], x[11n−1], . . . , x[11n−9] and x[11n−10], which are as the input signals for a set of parallel multichannel switch units  320   a ,  320   b , . . . ,  320   j ,  320   k , respectively. A software control unit  390  determines whether a symbol is 1 or 0 for all of the channels  311   a - 311   k . For example, channel  331   a , if the signal x[11n] is “1”, and then a switch  360   a  is connected to a position  330   a . Thus, a positive pulse bank  314  that contained an positive indoor shaped digital pulse or an positive outdoor shaped digital pulse is coupled to a D/A converter  318  to generate an analog shaped pulse y a (t) for the channel  331   a . The analog shaped pulse y a (t) is then multiplied by a carrier function of cos(2πf 1 t)  370   a  to produce the first bandpass signal for the channel  331   a . Otherwise, the switch  360   a  is connected to a position  330   b  if the signal x[n] is “0” symbol. A negative pulse bank  312 , which contained a negative indoor shaped digital pulse or a negative outdoor shaped digital pulse, is coupled to a D/A converter  316  to generate an analog shaped pulse y a (t) for the channel  331   a . Then, the analog shaped pulse y a (t) is multiplied by the carrier function of cos(2πf 1 t)  370   a  to produce the first bandpass signal for the channel  331   a . In a similar way, the polyphase multichannel-based multicarrier pulse generator  226  generates analog shaped pulses y a (t), . . . , y k (t) for all of the channels  311   a  to  311   k . Thus, the entire analog shaped pulses y a (t), . . . , y k (t) are coherently added together to pass a PA  224  through an antenna into air. 
   Referring to  FIG. 4  is a relationship  400  between a shaped digital pulse sequence and a binary symbol sequence based on a BPSK modulation for the multiband UWB communication transmitter according to some embodiments. A shaped digital pulse  410  represents “1” binary symbol while a shaped digital pulse  420  represents “0” binary symbol. The shaped digital pulse  410  is referred to as a “positive” pulse and the shaped digital pulse  420  is referred to as a “negative” pulse. A self-correlation of the shaped digital pulse  410  and  420  has a positive value close to “1”. On the other hand, a cross-correlation between the shaped digital pulse  410  and the shaped digital pulse  420  has a negative value close to “−1”. 
     FIG. 5  is a detailed block diagram  500  of a polyphase-based S/P multichannel based on a QPSK modulation for the indoor or outdoor operations according to some embodiments. In the detailed block diagram  550 , an input sequence x[n] with either 1 or 0 symbol sequence passes through the S/P unit  310  to generate 11 channel sequences  510   a - 510   k . Determining each channel of the sequences  510   a - 510   k  is based on the formula: {x[11n−1], x[11n]}; {x[11n−3], x[11n−2]}; {x[11n−5], x[11n−4]}; {x[11n−7], x[11n−6]}; {x[11n−9], x[11n−8]}; {x[11n−11], x[11n−10]}; {x[11n−13], x[11n−12]}; {x[11n−15], x[11n−14]}; {x[11n−17], x[11n−16]}; {x[11n−19], x[11n−18]}; and {x[11n−21], x[11n−20]}, for n=0, 2, 4, 6, . . . , respectively. On the other hand, using an alternative approach as shown in a block diagram  560  can also perform the polyphase-based S/P multichannel to achieve the same output as the block diagram  550  does. A switch  530  rotates connecting to one of the eleven positions  540   a - 540   k  at uniform speed. For example, the switch  530  is connected to the position  540   a  for the first channel when n=−1,0, 21, 22, . . . . The switch  530  is connected to the position  540   b  for the second channel when n=−3, −2, 19, 20, . . . , and so on. During the process, the switch  530  is controlled by a software control unit  390 . 
     FIG. 6  is a QPSK relationship  600  between the shaped digital pulse sequences and the binary symbol sequences based on every two symbols. A positive shaped digital pulse  610   a  represents two symbols “00”. The positive shaped digital pulse  610   b , with a delay time Δ, represents two symbols “01”. A negative shaped digital pulse  620   a  represents two symbols “11”. The negative shaped digital pulse  620   b  having the delay time Δ represents two symbols “10”. This expression uses one shaped digital pulse to represent two symbols for transmitting. 
   Referring to  FIG. 7  is impulse responses  700  of the positive indoor shaped digital pulse (h in [n])  710  and the negative indoor shaped digital pulse (−h in [n])  720 , with a linear phase. A difference between the positive indoor shaped digital pulse  710  and the negative indoor shaped digital pulse  720  is a phase difference. These two shaped digital pulses  710  and  720  are stored into the pulse banks  312  and  314 , where are ROM or RAM memory banks. The impulse response of the positive indoor shaped digital pulse  710  is listed in Table 3. 
   
     
       
             
             
             
           
         
             
                 
               TABLE 3 
             
             
                 
                 
             
             
                 
               Pulse taps 
               Value 
             
             
                 
                 
             
           
           
             
                 
               h[0] 
                8.4011931856093516e−005 
             
             
                 
               h[−1],h[1] 
                6.6460293297797776e−005 
             
             
                 
               h[−2],h[2] 
                3.4899656505824461e−005 
             
             
                 
               h[−3],h[3] 
                4.3116710798781203e−006 
             
             
                 
               h[−4],h[4] 
               −1.1214285545543695e−005 
             
             
                 
               h[−5],h[5] 
               −1.1091966005094216e−005 
             
             
                 
               h[−6],h[6] 
               −4.0631985867674594e−006 
             
             
                 
               h[−7],h[7] 
                1.6925543297452028e−006 
             
             
                 
               h[−8],h[8] 
                3.7995683513152043e−006 
             
             
                 
               h[−9],h[9] 
                3.5715207002110990e−006 
             
             
                 
               h[−10],h[10] 
                2.1069446071156423e−006 
             
             
                 
               h[−11],h[11] 
               −3.6643652826194515e−007 
             
             
                 
               h[−12],h[12] 
               −2.8164861523475095e−006 
             
             
                 
               h[−13],h[13] 
               −3.3131485713709617e−006 
             
             
                 
               h[−14],h[14] 
               −1.1423931641665744e−006 
             
             
                 
               h[−15],h[15] 
                1.8766255546648780e−006 
             
             
                 
               h[−16],h[16] 
                3.0434874609545600e−006 
             
             
                 
               h[−17],h[17] 
                1.5335471709233686e−006 
             
             
                 
               h[−18],h[18] 
               −9.2517743205833720e−007 
             
             
                 
               h[−19],h[19] 
               −2.0795608829123639e−006 
             
             
                 
               h[−20],h[20] 
               −1.3294520798670319e−006 
             
             
                 
               h[−21],h[21] 
                1.5173609022831139e−007 
             
             
                 
               h[−22],h[22] 
                1.0025701140610793e−006 
             
             
                 
               h[−23],h[23] 
                8.8427894743416094e−007 
             
             
                 
               h[−24],h[24] 
                3.2126248293514667e−007 
             
             
                 
               h[−25],h[25] 
               −1.6257131448705735e−007 
             
             
                 
               h[−26],h[26] 
               −4.2373069355925035e−007 
             
             
                 
               h[−27],h[27] 
               −4.9081265774967211e−007 
             
             
                 
               h[−28],h[28] 
               −3.2008852157750218e−007 
             
             
                 
               h[−29],h[29] 
                7.1976640681523624e−008 
             
             
                 
               h[−30],h[30] 
                4.4865425611366231e−007 
             
             
                 
               h[−31],h[31] 
                4.8145760999611724e−007 
             
             
                 
               h[−32],h[32] 
                1.1716686662078990e−007 
             
             
                 
               h[−33],h[33] 
               −3.2175597663148811e−007 
             
             
                 
               h[−34],h[34] 
               −4.3124038368895124e−007 
             
             
                 
               h[−35],h[35] 
               −1.5028657655143136e−007 
             
             
                 
               h[−36],h[36] 
                2.0356981673707622e−007 
             
             
                 
               h[−37],h[37] 
                2.8036698051837603e−007 
             
             
                 
               h[−38],h[38] 
                7.1364948530875849e−008 
             
             
                 
               h[−39],h[39] 
               −1.4582779654249872e−007 
             
             
                 
                 
             
           
        
       
     
   
   Referring to  FIG. 8  is a frequency response  800  of the positive and negative indoor shaped digital pulses  710  and  720 , respectively, according to some embodiments. The frequency response  800  is symmetric at the center frequency and is used for the use in the indoor UWB operations. 
   Now referring to  FIG. 9  are impulse responses  900  of the positive outdoor shaped digital pulse (h out [n])  910  and the negative outdoor shaped digital pulse (−h out [n])  920 , with a linear phase. A difference between the outdoor shaped digital pulse  910  and  920  is a 180-degree in phase. These two shaped digital pulses  910  and  920  are stored into the pulse banks  312  and  314 , where are ROM or RAM memory banks. The impulse response of the positive outdoor shaped digital pulse  910  is listed in Table 4. 
   
     
       
             
             
             
             
           
         
             
               TABLE 4 
             
             
                 
             
             
               Pulse Taps 
               Value 
               Coefficients 
               Pulse Taps 
             
             
                 
             
           
           
             
               h[0] 
                7.6488735705936605e−005 
               h[−21,],h[21] 
               −9.9696474129624093e−007 
             
             
               h[−1],h[1] 
                6.2636205884599369e−005 
               h[−22],h[22] 
                6.8001098631267257e−007 
             
             
               h[−2],h[2] 
                3.8360738472336015e−005 
               h[−23],h[23] 
                1.6055470083229580e−006 
             
             
               h[−3],h[3] 
                1.1315222826039952e−005 
               h[−24],h[24] 
                1.3544197859980424e−006 
             
             
               h[−4],h[4] 
               −7.5438087863256088e−006 
               h[−25],h[25] 
                2.8906713844065611e−007 
             
             
               h[−5],h[5] 
               −1.3715350107903802e−005 
               h[−26],h[26] 
               −7.7640460252440758e−007 
             
             
               h[−6],h[6] 
               −9.6549464333329795e−006 
               h[−27],h[27] 
               −1.1590268443143087e−006 
             
             
               h[−7],h[7] 
               −1.4025569435129311e−006 
               h[−28],h[28] 
               −7.2082016980864959e−007 
             
             
               h[−8],h[8] 
                5.3003810907673923e−006 
               h[−29],h[29] 
                1.0449113646872343e−007 
             
             
               h[−9],h[9] 
                7.2459334117828691e−006 
               h[−30],h[30] 
                7.0581527869524552e−007 
             
             
               h[−10],h[10] 
                4.3825454945279616e−006 
               h[−31],h[31] 
                7.2894825863413297e−007 
             
             
               h[−11],h[11] 
               −7.3762240948801741e−007 
               h[−32],h[32] 
                2.7772069871654161e−007 
             
             
               h[−12],h[12] 
               −4.5458747488001017e−006 
               h[−33],h[33] 
               −2.5824128353050490e−007 
             
             
               h[−13],h[13] 
               −4.7131566336279298e−006 
               h[−34],h[34] 
               −5.0913724964550914e−007 
             
             
               h[−14],h[14] 
               −1.6403017957724223e−006 
               h[−35],h[35] 
               −3.7669532172385286e−007 
             
             
               h[−15],h[15] 
                2.0411082705529443e−006 
               h[−36],h[36] 
               −3.2564239303970273e−008 
             
             
               h[−16],h[16] 
                3.6642171169389545e−006 
               h[−37],h[37] 
                2.4370835675220430e−007 
             
             
               h[−17],h[17] 
                2.4832733363889074e−006 
               h[−38],h[38] 
                2.9201867311458947e−007 
             
             
               h[−18],h[18] 
               −1.2626402560439206e−007 
               h[−39],h[39] 
                1.4137476178313894e−007 
             
             
               h[−19],h[19] 
               −2.1121354877069656e−006 
               h[−40],h[40] 
               −5.5504489846808052e−008 
             
             
               h[−20],h[20] 
               −2.3106300667210457e−006 
               h[−41],h[41] 
               −1.7766983155229356e−007 
             
             
                 
             
           
        
       
     
   
   Referring to  FIG. 10  is a frequency response  1000  of the outdoor shaped digital pulses  1010  and  1020  according to some embodiments. The frequency response  1010  is also symmetric about the center frequency and is used for outdoor UWB operations. 
   Referring to  FIG. 11  is a detailed block diagram  1100  of the negative pulse bank  312  and the positive pulse bank  314  according to some embodiments. The memory banks of  1120 ,  1122 ,  1170  and  1172  are RAMs or ROMs for storing the indoor shaped digital pulses  710  and  720 , and the outdoor shaped digital pulses  910  and  920 . The memory bank  1120  contains the positive indoor shaped digital pulse  710  while the memory bank  1170  includes the negative indoor shaped digital pulse  720 . The memory bank  1122  consists of the positive outdoor shaped digital pulse  910  while the memory bank  1172  has the negative outdoor shaped digital pulse  920 . The memory banks  1120  and  1122  are referred to as positive memory banks, and the memory banks  1170  and  1172  are called negative memory banks. There are two switch units  1124  and  1174 . The switch  1124  is called a positive pulse switch unit and the switch  1174  is referred to as a negative pulse switch unit. Switches  1124  and  1174  are controlled by using a software control  390 . The software control  390  can determine which one of positions should be connected to generate the shaped digital pulses for the BPSK or QPSK modulation during the indoor or outdoor UWB operations. 
     FIG. 12  is an output frequency spectrum  1200  of the polyphase multichannel-based multicarrier pulse generator for the indoor UWB operation, including 11 transmitter channel spectrums  1220 A- 1220 K according to some embodiments. An indoor FCC emission limitation  1210  is also shown in  FIG. 12 . Each channel has a frequency bandwidth of 650 MHz. As can be seen, all of the channels are fitted under the indoor FCC emission limitation  1210  with different carrier frequencies. The detail positions of each transmitter channel spectrum (dBm) along with the center, lower and upper frequencies (GHz) as well as channel frequency bandwidth (MHz) are listed in Table 5. 
   
     
       
             
             
             
             
             
           
         
             
               TABLE 5 
             
             
                 
             
             
                 
               Center 
               Lower 
               Upper 
                 
             
             
               Multichannel 
               Frequency 
               Frequency 
               Frequency 
               Frequency 
             
             
               Label 
               (GHz) 
               (GHz) 
               (GHz) 
               Bandwidth (MHz) 
             
             
                 
             
           
           
             
               1220A 
               3.45 
               3.125 
               3.775 
               650 
             
             
               1220B 
               4.10 
               3.775 
               4.425 
               650 
             
             
               1220C 
               4.75 
               4.425 
               5.075 
               650 
             
             
               1220D 
               5.40 
               5.075 
               5.725 
               650 
             
             
               1220E 
               6.05 
               5.725 
               6.375 
               650 
             
             
               1220F 
               6.70 
               6.375 
               7.025 
               650 
             
             
               1220G 
               7.35 
               7.025 
               7.675 
               650 
             
             
               1220H 
               8.00 
               7.675 
               8.325 
               650 
             
             
               1220I 
               8.65 
               8.325 
               8.975 
               650 
             
             
               1220J 
               9.30 
               8.975 
               9.625 
               650 
             
             
               1220K 
               9.95 
               9.625 
               10.275  
               650 
             
             
                 
             
           
        
       
     
   
     FIG. 13  is an output frequency spectrum  1300  of the polyphase multichannel-based multicarrier pulse generator for the outdoor UWB operation, including 11 transmitter channel spectrums  1320 A- 1320 K along with the outdoor FCC emission limitation  1310  according to some embodiments. Each channel also has a frequency bandwidth of 650 MHz. It is also clear that all of the channels at different carrier frequencies are fitted under the outdoor FCC emission limitation  1310 . 
     FIG. 14  is a block diagram of a multiband UWB communication receiver  1400  for the indoor and outdoor operations according to some embodiments. A low noise amplifier (LNA)  1410 , which is coupled to an automatic gain control (AGC)  1420 , receives the UWB signals from an antenna. The output of LNA  1410  is passed through the AGC  1420  to adjust amplitude of the UWB signals for a multichannel-based multicarrier down converter  1430 . A software and time control  1440  is use to control the AGC  1420  and the multichannel-based multicarrier down converter  1430 . The bandlimited UWB analog signals of the output multichannel-based multicarrier down converter  1430  are then sampled and quantized by using an A/D converter  1432  at a sampling rate of 720 MHz. The output digital signals of the A/D converter  1432  are filtered by using an indoor or outdoor digital receiver lowpass filter  1434  to remove the out of band signals. The indoor or outdoor digital receiver lowpass filter  1434  is controlled by a software and time control  1440 . The output data of the digital receiver lowpass filter  1434  is used for a rake receiver  1436 . A channel estimator  1442  is used to estimate a channel phase and frequency. The channel phase and frequency information are then passed into the rake receiver  1436 . The rake receiver  1436  calculates a correlation between the received UWB pulse signals and template pulses, which are provided by using a template pulse generator  1450 , and performs a coherent combination. The output of the rake receiver  1436  is passed to an equalizer  1444 , which also receives the channel phase and frequency information from the channel estimator  1442 , to eliminate inter-symbol interference (ISI), inter-channel interference (ICI), and inter-pulse interference (IPI). Then, the output symbol data of the equalizer  1444  is passed to a de-interleaver  1446 . Thus, the symbol data is de-interleaved by using the de-interleaver  1446 . The output symbol data of the de-interleaver  1446  is used for Viterbi decoder  1448  to decode the encoded data and to produce the user data bits at 3,575 Mbps. The entire section unit  1460  is referred to as a polyphase multichannel combiner of the multicarrier down converter. 
   Referring to  FIG. 15  is a detailed block diagram  1500  of the polyphase multichannel combiner of the multicarrier down converter  1460  according to the present invention. The received signals r(t) are formed 11 channel signals labeled with  1502   a - 1502   k , which are multiplied by carrier frequency functions of cos(2πf 1 t), . . . , cos(2πf 11 t), to produce the output signals r 1 (t), . . . , r 11 (t), respectively. In a parallel form, all of the signals r 1 (t), . . . , r 11 (t) are then passed to a set of parallel anti-aliasing analog filters  1520   a - 1520   k , which produce the bandlimited signals for a set of parallel A/D converters  1530   a - 1530   k  followed by digital receiver lowpass filters  1540   a - 1540   k . Then, the output signals of the digital receiver filters  1540   a - 1540   k  are used for a set of rake receivers  1550   a - 1550   k  to perform correlation measures between the received pulses and the template pulses, which are generated from the template pulse generator  1450 . Thus, the output channel signals r[11n+10], . . . , rs[11n] of the rake receiver  1550   a - 1550   k  are combined by using a polyphase upsampling structure to generate the output sequence. 
   Referring to  FIG. 16  is a detailed block diagram  1600  of a polyphase-based parallel-to-serial (P/S)  1560  according to one embodiment. The input sequence, including 11 channels  1620   a - 1620   k  in parallel, has a length of symbol M. A switch  1630  rotates from a position  1620   k  to a position  1620   a  with a uniform speed at every two symbols to produce an output sequence with a symbol length of 11M. A software and time control  1440  controls the switch  1630  during the operation. The speed of the switch  1630  is adjustable at a uniform speed for a different number of symbols. 
   While the present invention has been described with respect to a limited number of embodiments, those skilled in the art will appreciate numerous modifications and variations therefrom. It is intended that the appended claims cover all such modifications and variations as fall within the true spirit and scope of the present invention.