Abstract:
This invention presents a system of a multiband MIMO-based W-CDMA and UWB communications for wireless and local area wireless communications. The system includes a W-CDMA base station, an UWB base station, and p-user dual-mode W-CDMA and UWB portable stations. This system allows p-user to transmit and receive a very high-speed multimedia information data based on W-CDMA and UWB communications to access both wireless phones and Internet.

Description:
BACKGROUND 
   This invention is generally relative to a multiband Multiple-Input-Multiple-Output (MIMO)-based Wideband Code Division Multiple Access (W-CDMA) and Ultra Wideband (UWB) Communications for wireless and/or local-area wireless communications. 
   A MIMO is a multiple-input-multiple-output as a wireless link and is also a space-time signal processing. In the space-time signal processing a natural dimensional of transmitting data is complemented with a spatial dimension inherent in the use of multiple spatially distributed antennas. Thus this leads that the MIMO is able to turn multipath propagation into benefit for a user. In a MIMO system, signals on the transmit antennas and the receiver antennas are integrated in such a way that a quality of bit error rate (BER) or a data rate of the communication for each user or a transmitting distance is improved, thereby increasing a communication network&#39;s quality of service. 
   The next-generation wireless communication is defined to allow a subscriber to access World Wide Web or to perform file transferring over packet data connections capable of providing 144 kbps and 384 kbps for a mobility, and 2 Mbps in an indoor environment. The W-CDMA is a wideband, spread spectrum radio interface that uses CDMA technology to meet the needs for the next-generation wireless communication. The W-CDMA (also known as CDMA2000) supports for a wide range of radio frequency (RF) channel bandwidths from 1.25 MHz to 15 MHz operating at 1.90 GHz band, where the channel sizes of 1, 3, 6, 9, and 12×1.25 MHz. A wide channel of the W-CDMA offers any combination of higher data rates, thereby enhancing total capacity. The W-CDMA also employs a single carrier and a multicarrier system, which can be deployed as an overlay over one or more existing the second generation of TIA/EIA-95B1.25 MHz channels. In a multicarrier system, modulation symbols are de-multiplexed onto N separate 1.25 MHz carriers. Each carrier is spread with a 1.2288 Mcps chip rate. 
   With regard to the UWB communications, U.S. Federal Communications Commission (FCC) released a revision of Part 15 of Commission&#39;s rules for UWB transmission systems on Apr. 22, 2002. FCC permitted the marketing and operation of certain types of new products, incorporating UWB technology. Thus, UWB communication devices can operate using spectrum occupied by existing radio service without causing interference. This results permitting scarce spectrum resources to be used more efficiently. The UWB communication devices can offer significant benefits for Government, public safety, businesses and consumers under an unlicensed basis of an operation spectrum. 
   FCC is adapting unwanted emission limits for the UWB communication devices that are significantly more stringent than those imposed on other Part 15 devices. For an indoor UWB operation, FCC provides a wide variety of the UWB communication 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. However, the UWB communication devices must operate in the frequency band ranges from 3.1 GHz to 10.6 GHz, and have an emission of −10 dBm for the indoor UWB operation. In addition, the UWB communication devices should also satisfy the Part 15.209 limit for the frequency band below 960 MHz. Table 1 lists the FCC restriction of the emission masks (dBm) along with the frequencies (GHz) for the UWB communication devices in an indoor environment. 
   
     
       
             
             
             
           
         
             
                 
               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 
             
             
                 
                 
             
           
        
       
     
   
   The UWB communication devices are defined as any devices where a fractional bandwidth (FB) is greater than 0.25 based on the following formula: 
                   FB   =     2   ⁢     (         f   H     -     f   L           f   H     +     f   L         )         ,           (   1   )               
where f h  is the upper frequency of −10 dBm emission point, and f L  is the lower frequency of −10 dBm emission point. A center transmission frequency F c  of the UWB communication devices is defined as an average of the upper and lower −10 dBm emission points as follows:
 
                   F   C     =           f   H     +     f   L       2     .             (   2   )               
Furthermore, a minimum frequency bandwidth of 500 MHz must be used for indoor UWB communication devices regardless of the center frequency.
 
   The UWB communication devices can be designed to use for wireless broadband communications within a short-distance range, particularly for a very high-speed data transmission suitable for broadband access to networks in the indoor environment. 
   A multiband MIMO-based W-CDMA and UWB communication transceiver system is disclosed herein according to some embodiments of the present invention. The invention system includes a W-CDMA base station, a UWB base station, and P-user dual-mode portable stations of W-CDMA and UWB communication devices. The W-CDMA base station has a multicarrier for 12 channels with a total of 15 MHz frequency bandwidth at the center of 1.9 GHz frequency band, and employs four antennas at the transmitter and receiver. The UWB communication base station uses a multicarrier for four frequency bands (referred to as a multiband) with a total of 2.048-GHz frequency bandwidth in the frequency range from 3.1 GHz to 5.15 GHz, and also employs four antennas at the transmitter and receiver. Each of the frequency bands in the UWB communications has a 512-MHz frequency bandwidth, using an Orthogonal Frequency Division Multiplexing (OFDM) modulation. On the other hand, each of the P-user dual-mode portable stations of the W-CDMA and UWB communication devices uses two antennas, and shares some of common components, such as analog-to-digital (A/D) and digital-to-analog (D/A) converters, memory, etc. The W-CDMA in the dual-mode portable stations uses 12 channels with each channel of 1.25 MHz, has a multicarrier, and is able to transmit a data rate more than 2 Mcps, while the UWB employs four frequency band-based multicarrier OFDM with each frequency band of 512 MHz, and can transmit a data rate up to 1.5872 Gbps. In addition, all of the dual-mode portable station use a direct sequence spread spectrum (DSSS), which is a pseudorandom (PN) sequence to spread a user signal. The DSSS is used to separate signals coming from multiuser. Thus, multiple access interference (MAI) among multiuser can be avoided when a set of PN sequences is designed with as low cross-correlation as possible. 
   An OFDM is an orthogonal multicarrier modulation technique that has its capability of multifold increasing symbol duration. Increasing the number of subcarriers in the OFDM modulation, the frequency selectivity of a channel may be reduced so that each subcarrier experiences flat fading for the UWB communications. Thus, an OFDM approach is a particular useful for the UWB communications over a short-range fading channel. 
   The present invention of the multiband MIMO-based W-CDMA and UWB communications utilizes both benefits of W-CDMA wireless phones and UWB wireless broadband communications. Such a dual-mode device not only can transmit the packet data in a form of wireless phone but also can use as a very-high speed wireless broadband Internet device to transmit and receive data, image, video, video game, music, and stock graph, etc., in a real-time. Thus, there is a continuing need of the multiband MIMO-based W-CDMA and UWB communication transceiver system for delivering a very-high data rate with a capability of flexibility and scalability in a combination form of the wireless and fixed wireless environment. 
   SUMMARY 
   In accordance with one aspect, a multiband MIMO-based dual-mode portable station of W-CDMA and UWB communication receiver comprises a MIMO-based dual-mode W-CDMA and UWB filtering and multicarrier Radio Frequency (RF) section, a W-CDMA baseband processor, an UWB OFDM multiband baseband processor, a W-CDMA and UWB OFDM multiband control processor, and a multiple antenna unit. 
   Other aspects are set forth in the accompanying detailed description and claims. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a block diagram of shewing a multiband MIMO-based W-CDMA and UWB communication transceiver system including P-user dual-mode portable stations of W-CDMA and UWB, and two different base stations of the W-CDMA and UWB communication according to some embodiments. 
       FIG. 2  is a block diagram of a MIMO-based W-CDMA base station employing four antennas according to some embodiments. 
       FIG. 3  is a detailed block diagram of a W-CDMA baseband processor of the base station according to some embodiments. 
       FIG. 4  is a detailed block of a MIMO-based W-CDMA filtering and multicarrier RF section according to some embodiments. 
       FIG. 5  is a detailed block diagram of a W-CDMA mapping, spreading, and filtering section according to some embodiments. 
       FIG. 6  is a detailed block diagram of a W-CDMA analog filtering and multicarrier modulation section according to some embodiments. 
       FIG. 7  is a block diagram of a MIMO-based UWB base station according to some embodiments. 
       FIG. 8  is a detailed block diagram of an UWB base station according to some embodiments. 
       FIG. 9  is a detailed block diagram of a MIMO-based UWB spreading and filtering section according to some embodiments. 
       FIG. 10  is a detailed block diagram of a MIMO-based UWB modulation and multicarrier RF section according to some embodiments. 
       FIG. 11  is a frequency spectrum output of the MIMO-based UWB base station transmitter for the indoor operation according to one embodiment. 
       FIG. 12  is a block diagram of a W-CDMA and UWB portable station for a single user according to some embodiments. 
       FIG. 13  is a detailed block diagram of a MIMO-based dual-mode 3G W-CDMA and UWB filtering and multicarrier RF section according to some embodiments. 
       FIG. 14  is a detailed block diagram of a W-CDMA down converter and demodulation according to some embodiments. 
       FIG. 15  is a detailed block diagram of an UWB multiband down converter and demodulation according to some embodiments. 
       FIG. 16  is a detailed block diagram of an analog-to-digital converter according to some embodiments. 
       FIG. 17  is a detailed block diagram of a W-CDMA baseband processor in the dual-mode portable station according to some embodiments. 
       FIG. 18  is a detailed block diagram of a W-CDMA multiband rake receiver and decoder unit according to some embodiments. 
       FIG. 19  is a detailed block diagram of a UWB OFDM multiband baseband processor according to some embodiments. 
       FIG. 20  is a detailed block diagram of a combination section of a digital receiver filter unit, a multiband despreading unit, and a time-domain equalizer (TEQ) unit according to some embodiments. 
       FIG. 21  is a detailed block diagram of a combination section of a fast Fourier transform (FFT) unit and a frequency-domain equalizer (FEQ) unit according to some embodiments. 
       FIG. 22  is a detailed block diagram of a despreading, deinterleaver, and decoding unit according to some embodiments. 
   

   DETAILED DESCRIPTION 
   Some embodiments described herein are directed to the multiband MIMO-based W-CDMA and UWB transceiver system for wireless and fixed wireless communications. Such a dual-mode transceiver system can be implemented in hardware, such as in an Application Specific Integrated Circuits (ASIC), digital signal processor, field programmable gate array (FPGA), software, or a combination of hardware and software. 
   Multiuser MIMO-Based 3G W-CDMA and UWB System 
   A multiuser MIMO-based W-CDMA and UWB system  100  for the wireless and fixed wireless communications is shown in  FIG. 1  in accordance with one embodiment of the present invention. Dual-mode W-CDMA and UWB portable stations from  110   a  to  110   p  can simultaneously communicate with either a MIMO-based W-CDMA base station  140  or a MIMO-based UWB base station  170  to transmit and receive information data. The dual-mode W-CDMA and UWB portable station  110   a  transmits and receives the W-CDMA or the UWB information data through its two antennas of  120   a   1  and  120   a   2 . The base station of the W-CDMA  140  or the UWB base station  170  communicates with the dual-mode W-CDMA and UWB portable station  110   a  through the W-CDMA&#39;s four antennas from  130   a  to  130   d  or through the UWB&#39;s four antennas from  160   a  to  160   d , respectively. In a similar way, other dual-mode W-CDMA and UWB portable stations from  110   b  to  110   p  also transmit and receive the information data through their antennas from  120   b   1  and  120   b   2  to  120   p   1  and  120   p   2 , respectively, and communicate with either the W-CDMA base station  140  through the antennas from  130   a  to  130   d  or the UWB base station  170  through the antennas from  160   a  to  160   d . The W-CDMA base station  140  is coupled to a W-CDMA network interface section  150 , which is connected with a W-CDMA network  152 . The UWB base station  170  is connected with an UWB network interface section  180  that is coupled to an UWB network  182 . 
   The MIMO-based W-CDMA base station  140  can transmit multiuser&#39;s information data at the same time. After scrambling with a long code corresponding to user p, the user data is de-multiplexed onto N carriers, where N equals to 3, 6, 9, or 12. On each carrier, the demultiplexed bits are mapped onto I and Q followed by using Walsh spreading. For reverse closed loop power control, power control bits may be punctured onto the forward link channel at a rate of 800 Hz. Then, a signal on each carrier is orthogonally spread by an appropriate Walsh code function in such a way that a fixed chip rate of 1.2288 Mcps can be maintained per carrier. Walsh codes may differ on each carrier. The signal on each carrier is then complex PN spread followed by using a baseband filtering and binary phase-shifted keying (BPSK) or quaternary phase-shifted keying (QPSK) modulation. The W-CDMA base station  140  can transmit and receive the data rate from 144 kbps to greater than 2 Mbps and supports a wide range of RF channel bandwidths, including 1.25 MHz, 3.75 MHz, 7.5 MHz, 11.25 MHz, and 15 MHz. 
   The MIMO-based UWB base station  170 , knowing all of the UWB PN sequences of the dual-mode W-CDMA and UWB portable stations from  110   a  to  110   p , can transmit and receive all of the UWB information data from all of the dual-mode W-CDMA and UWB portable stations from  110   a  to  110   p  by spreading and despreading of the user PN sequences on the multiband. The MIMO-based UWB base station  170  uses a BPSK or a QPSK modulation and a carrier for each of the multiband to transmit and receive the information data rate of 396.8 Mbps on one frequency band. As a result, the MIMO-based UWB base station  170  can simultaneously transmit and/or receive the maximum data rate up to 1.5872 Gbps by using all of the four frequency bands. In addition, the UWB base station  170  is able to transmit the data rate with an enhancement of a longer range due to use the multiple antennas. 
   3G W-CDMA Base Station Transmitter Architecture 
     FIG. 2  is a block diagram  200  of the MIMO-based W-CDMA base station  140  according to some embodiments. The MIMO-based W-CDMA base station  140  includes a W-CDMA baseband processor  210 , a MIMO-based W-CDMA filtering and multicarrier RF section  220  coupled to four antennas from  130   a  to  130   d , and a W-CDMA control processor  230 . The W-CDMA baseband processor  210  deals with a multiuser digital signal processing of a physical layer including turbo or convolution encoder and decoder, block interleaver and deinterleaver, spreading and dispreading. The MIMO-based W-CDMA filtering and multicarrier RF section  220  provides filtering, modulation, and transmits W-CDMA signal through the antennas from  130   a  to  130   d . The W-CDMA control processor  230  supports a data frame information, and controls the W-CDMA baseband processor  210  and the MIMO-based W-CDMA filtering and multicarrier RF section  220 . 
   The MIMO-based W-CDMA base station  140  is able to transmit and receive multiuser information data through multichannel with multicarrier simultaneously. There are a total of 12 multicarriers for a wide range of RF channel bandwidths of 1.25 MHz, 3.75 MHz, 7.5 MHz, 11.25 MHz, and 15 MHz. The signal on each carrier is orthogonally spread by the appropriate Walsh code at the chip rate of 1.2288 Mcps. Then, the signal on each carrier is filtered and modulated by using the baseband filtering and BPSK or QPSK modulation. The MIMO-based W-CDMA base station  140  can transmit and/or receive the data rate from 144 kbps to more than 2 Mbps. 
   Referring to  FIG. 3  is a detailed block diagram  300  of the W-CDMA baseband processor  210  according to some embodiments. A turbo or convolution encoder  310  that is used to encode the user information data is coupled to a symbol repetition  320 . The symbol repetition  320  can repeat a frame symbol data with 2-time, 4-time or 8-time. The output of the symbol repetition  320  is interleaved by using a block interleaver  330 . The output data of the block interleaver  330  is scrambled with a long code from a bit selector  360  by using an exclusive OR (XOR)  370 . A long code mask for user p  340  is coupled to a long code generator  350  that is connected with a bit selector  360 . The scrambled data of the XOR  370  output is demultiplexed onto 12 parallel data labeled from d 1  to d 12  by using a demultiplexer  380 . 
     FIG. 4  is a block diagram  400  of the MIMO-based W-CDMA filtering and multicarrier RF section  220  according to some embodiments. The MIMO-based 3G W-CDMA filtering and multicarrier RF section  220  includes a W-CDMA mapping spreading and filtering  410  and a W-CDMA analog filtering and multicarrier modulation  420 . The W-CDMA mapping spreading and filtering  410  is coupled to the W-CDMA analog filtering and multicarrier modulation  420 . The 12 parallel signals from d 1  to d 12  are passed through the W-CDMA mapping spreading and filtering  410  to produce 12 parallel output signals, which are used as the input signals for the W-CDMA analog filtering and multicarrier modulation  420 . Then the W-CDMA analog filtering and multicarrier modulation  420  produces four parallel signals for the transmitter through four antennas from  130   a  to  130   d.    
   Referring to  FIG. 5  is a detailed block diagram  500  of the W-CDMA mapping, spreading and filtering  410  according to some embodiments. The 12 parallel input signals from d 1  to d 12  are passed through  12  MUX and IQ mapping units from  510   a  to  510   m . The output I and Q signals of the MUX and IQ mapping units from  510   a  to  510   m  are spread by using Walsh codes from W m1  to W m12 , respectively. Then signals are complex PN spread by using complex PN spreading units from  530   a  to  530   m , followed by baseband filters from  540   a   1  and  540   a   2  to  540   m   1  and  540   m   2 . Analog-to-digital (A/D) converter units from  550   a   1  and  550   a   2  to  550   m   1  to  550   m   2  convert all of the digital signals of the baseband filter outputs from  540   a   1  and  540   a   2  to  540   m   1  and  540   m   2  into parallel analog signals from a 11  and a 12  to a 121  and a 122 . 
   Referring to  FIG. 6  is a detailed block diagram  600  of the W-CDMA analog filtering and multicarrier modulation  420  according to some embodiments. The input signals from a 11  and a 12  to a 121  and a 122  are in parallel passed through analog filters from  610   a   1  and  610   a   2  to  610   m   1  and  610   m   2  to produce reconstructed analog signals. Each pair of the output signals of the analog filters from  610   a   1  and  610   a   2  to  610   m   1  and  610   m   2  is performed QPSK modulation with multicarrier by using each pair of multipliers  620   a   1  and  620   a   2  and one addition  630   a   1  to multipliers  620   m   1  and  620   m   2  and one addition  630   m , respectively. The 12 QPSK signals with multicarriers are grouped together into four signals by using four additions from  640   a  to  640   d , respectively, followed by four baseband filters (BPF) from  650   a  to  650   d  to produce signals for power amplifier and antennas. 
     FIG. 7  is a block diagram  700  of the MIMO-based UWB base station  170  according to some embodiments. An UWB baseband processor  710 , which performs convolution encoder and decoder, interleaver and deinterleaver, and inverse fast Fourier transform (IFFT) and fast Fourier transform (FFT) functions, is coupled to a MIMO-based UWB spreading and filtering  720 , followed by a MIMO-based UWB modulation and multicarrier RF section  730 . The MIMO-based UWB modulation and multicarrier RF section  730  is connected with four antennas from  160   a  to  160   d . An UWB control processor  740  is used to control a frame information and entire process among the units of the MIMO-based UWB base station  170 , the MIMO-based UWB spreading and filtering  720 , and MIMO-based UWB modulation and multicarrier RF section  730 . 
   Referring to  FIG. 8  is a detailed block diagram  800  of the UWB baseband processor  710  according to some embodiments. There are a number of p users from a user-1 bitstream  810   a  to a users bitstream  810   p , respectively. The user-1 bitstream  810   a  is coupled to a ½-rate convolution encoder  812   a  that is connected to an interleaver  814   a . Using a unique PN sequence of a user-1 key  822   a  spreads the output sequence of the interleaver  814   a . In a similar way, the user-p bitstream  810   p  is coupled to the ½-rate convolution encoder  812   p  that is connected to the interleaver  814   p . Using the unique PN sequence of the user-p key  822   p  spreads the output sequences of the interleaver  814   p . All of the PN sequences of the user-1 key  822   a  to the users key  822   p  are orthogonal each other. This means that a cross-correlation between one PN sequence and other PN sequences is almost zero, while a self-correlation of a user PN sequence is almost equal to one. Then, the p output sequences from the interleaver  814   a  to the interleaver  814   p  in a parallel operation are added together to form a serial sequence output by using a sum over block duration  830 . The serial output of the sum over block duration  830  is converted into four parallel sequences by using a polyphase-based multiband  840 . Thus, the first of the output sequence from the polyphase-based multiband  840  is converted into a 512-parallel sequence by using a serial-to-parallel (S/P)  850   a . The 512-parallel sequence is formed to a 512-parallel complex sequence with symmetric conjugates. The 512-parallel complex sequence is passed through an IFFT  852   a  to produce a 1024-parallel real sequence. The IFFT  852   a  is coupled to a guard  854   a  to insert 256 samples as a guard interval for the output sequence of the IFFT  852   a . As a result, the output of the guard  854   a  is a 1280-parallel real sequence. Then, the outputs of the guard  854   a  are used to form a serial signal p 1  by using a parallel-to-serial (P/S)  856   a . In the same way, the fourth of the output sequence from the polyphase-based multiband  840  is converted into a 512-parallel sequence by using a S/P  850   k . The 512-parallel sequence is formed to a 512-parallel complex sequence with symmetric conjugates. The 512-parallel complex sequence is passed through an IFFT  852   d  to produce a 1024-parallel real sequence. The IFFT  852   d  is coupled to a guard  854   d  to insert 256 samples as a guard interval for the output sequence of the IFFT  852   d . Thus, the output of the guard  854   d  is a 1280-parallel real sequence. The guard interval is used to avoid an intersymbol interference (ISI) between IFFT frames. Finally, the outputs of the guard  854   d  are used to form a serial signalp 4  by using a P/S  856   d.    
   The data rate-dependent parameters of the 1024-point IFFT operation  852  is listed in Table 2 for each of the frequency bands as follows: 
   
     
       
             
             
             
             
             
             
             
           
         
             
               TABLE 2 
             
             
                 
             
             
               Four band 
               One 
                 
                 
                 
                 
                 
             
             
               frequency 
               frequency 
                 
                 
               Coded bits 
               Coded bits 
               Data bits per 
             
             
               data rate 
               band data rate 
                 
               Coding 
               per sub- 
               per OFDM 
               OFDM 
             
             
               (Gbits/s) 
               (Mbits/s) 
               Modulation 
               rate 
               carrier 
               symbol 
               symbol 
             
             
                 
             
           
           
             
               0.7936 
               198.4 
               BPSK 
               1/2 
               1 
                992 
               496 
             
             
               1.5872 
               396.8 
               QPSK 
               1/2 
               2 
               1984 
               992 
             
             
                 
             
           
        
       
     
   
   The corresponding 1024-point IFFT of detailed timing-related parameters for each of the frequency bands is listed in Table 3: 
   
     
       
             
             
             
           
         
             
               TABLE 3 
             
             
                 
             
             
               Parameters 
               Descriptions 
               Value 
             
             
                 
             
           
           
             
               N ds   
               Number of data subcarriers 
               992 
             
             
               N ps   
               Number of pilot subcarriers 
               8 
             
             
               N ts   
               Number of total subcarriers 
               1000 
             
             
               D fs   
               Frequency spacing for subcarrier (512 
               0.5 MHz 
             
             
                 
               MHz/1024) 
             
             
               T FFT   
               IFFT/FFT period (1/D fs ) 
               2.0 μs 
             
             
               T gd   
               Guard duration (T FFT /4) 
               0.5 μs 
             
             
               T signal   
               Duration of the signal BPSK-OFDM symbol 
               2.5 μs 
             
             
                 
               (T FFT  + T gd ) 
             
             
               T sym   
               Symbol interval (T FFT  + T gd ) 
               2.5 μs 
             
             
               T short   
               Short duration of training sequence (10 × 
               5.0 μs 
             
             
                 
               T FFT /4) 
             
             
               T gd2   
               Training symbol guard duration 
               1.0 μs 
             
             
                 
               (T FFT /2) 
             
             
               T long   
               Long duration of training sequence (2 × T FFT  + 
               5.0 μs 
             
             
                 
               T gd2 ) 
             
             
               T preamble   
               Physical layer convergence procedure preamble 
               10.0 μs 
             
             
                 
               duration (T short  + T long ) 
             
             
                 
             
           
        
       
     
   
   Referring to  FIG. 9  is a detailed block diagram  900  of the MIMO-based spreading and filtering section  720  according to some embodiments. There are four input signals from p 1  to P 4 . The input signal of p 1  is demultiplexed by using a demultiplexer  910   a  to produce I and Q signals. The I and Q signals are spread with an output sequence of a multiband spreading  930   a  by using XORs of  920   a  and  920   b  to produce spread I and Q signals, followed by two transmitter shaped filters of  940   a , and  940   a   2 , respectively. Then, the output signals of the transmitter shaped filters of  940   a   1  and  940   a   2  are passed through two D/A converters of  950   a   1  and  950   a   2 , followed by two analog filters of  960   a   1  and  960   a   2  to smooth the analog signals, respectively. In the same way, the input signal of p 4  is demultiplexed by using a demultiplexer  910   d  to produce I and Q signals. The I and Q signals are spread with an output sequence of a multiband spreading  930   d  by using XORs  920   d   1  and  920   d   2  to produce spread I and Q signals, followed by two transmitter shaped filters of  940   d   1  and  940   d   2 , respectively. Then, the output signals of the transmitter shaped filters of  940   d   1  and  940   d   2  are passed through two D/A converters of  950   d   1  and  950   d   2 , followed by two analog filters of  960   d   1  and  960   d   2  to smooth the analog signals, respectively. Thus, the MIMO-based spreading and filtering section of 720 converts four digital sequences onto four I and four Q spread analog signals with multicarrier for transmitter section. 
   Referring to  FIG. 10  is a detailed block diagram  1000  of the MIMO-based UWB modulation and multicarrier RF section  730  according to some embodiments. The input signals from I 1  and Q 1  to I 4  and Q 4  are modulated in a QPSK format with multicarriers by using multipliers of  1010   a   1  and  1010   a   2  and an addition from  1012   a  to  1010   d   1  and  1101   d   2  and an addition  1012   d  to produce RF signals from o 1  to o 2 . Then, the signals from o 1  to o 2  are summed together to form four RF signals with multicarriers by using additions from  1020   a  to  1020   d , followed by using analog bandpass filters from  1030   a  to  1030   d . The output RF signals of the analog bandpass filters from  1030   a  to  1030   d  are passed through the power amplifier (PA) from  1040   a  to  1040   d  onto antennas. 
   Spectrums of MIMO-Based UWB Base Station Transmitter 
     FIG. 11  is an output frequency spectrum  1100  of the MIMO-based UWB base station communication transmitter, including four frequency band spectrums of  1120 ,  1130 ,  1140  and  1150  according to some embodiments. A FCC emission limitation  1110  for the indoor UWB operation is also shown in  FIG. 11 . Each transmitter frequency bandwidth of all the frequency band spectrums of  1120 ,  1130 ,  1140  and  1150  is 512 MHz and is fitted under the indoor FCC emission limitation  1110  with different carrier frequencies. The detail positions of each frequency band spectrums (dBm) along with the center, lower and upper frequencies (GHz) as well as the channel frequency bandwidth (MHz) are listed in Table 4: 
   
     
       
             
             
             
             
             
           
         
             
               TABLE 4 
             
             
                 
             
             
                 
               Center 
               Lower 
                 
               Frequency 
             
             
               Multichannel 
               Frequency 
               Frequency 
               Upper Frequency 
               Bandwidth 
             
             
               Label 
               (GHz) 
               (GHz) 
               (GHz) 
               (MHz) 
             
             
                 
             
           
           
             
               1120 
               3.357 
               3.101 
               3.613 
               512 
             
             
               1130 
               3.869 
               3.613 
               4.125 
               512 
             
             
               1140 
               4.381 
               4.125 
               4.637 
               512 
             
             
               1150 
               4.893 
               4.637 
               5.149 
               512 
             
             
                 
             
           
        
       
     
   
   During the indoor UWB operation, the MIMO-based UWB base station transmitters can avoid interference with wireless local area network (WLAN) 802.11a lower U-NII frequency band in the frequency range of 5.15 GHz to 5.35 GHz since the highest spectrum of the MIMO-based UWB base station transmitter is at 5.149 GHz, which is lower than 5.15 GHz in WLAN 802.11a lower band. 
   Dual-Mode MIMO-based Receiver of 3G W-CDMA and UWB Portable Station 
     FIG. 12  is a block diagram  1200  of a dual-mode MIMO-based receiver of the W-CDMA and UWB portable station  110   a  according to some embodiments. A dual-mode MIMO-based W-CDMA, UWB filtering and multicarrier RF section  1210  receives RF signals from two antennas of  120   a   1  and  120   a   2  and converts RF signals to either W-CDMA digital signals or UWB digital signals. The dual-mode MIMO-based W-CDMA, UWB filtering and multicarrier RF section  1210  is coupled to a W-CDMA baseband processor  1220  and an UWB OFDM multiband baseband processor  1230 . During the W-CDMA mode, the W-CDMA baseband processor  1220  receives the W-CDMA digital signals from the dual-mode MIMO-based W-CDMA, UWB filtering and multicarrier RF section  1210  to perform digital filtering, demultiplexer, rake receiver, dispreading, deinterleaver, and decoding processes. During the UWB mode, the UWB OFDM multiband baseband processor  1230  receives the UWB digital signals from the dual-mode MIMO-based W-CDMA, UWB filtering and multicarrier RF section  1210  to deal with digital filtering, multiband dispreading, time-domain equalizer (TEQ), FFT, frequency-domain equalizer (FEQ), dispreading, deinterleaver, and decoding. A W-CDMA and UWB OFDM multiband control processor  1240  is used to control data flow among blocks of the dual-mode MIMO-based W-CDMA, UWB filtering and multicarrier RF section  1210 , the W-CDMA baseband processor  1220 , the UWB OFDM multiband baseband processor  1230 , and a sharing memory bank  1250 . 
   Referring to  FIG. 13  is a detailed block diagram  1300  of showing the dual-mode MIMO-based W-CDMA, UWB filtering and multicarrier RF section  1210  according to some embodiments. Two low noise amplifiers (LNA) of  1310   a  and  1310   b  receive RF signals from two antennas, respectively, and amplify RF signals. The LNA of  1310   a  and  1310   b  respectively connect with two automatic gain controls (AGC) of  1320   a  and  1320   b , followed by two analog baseband filters of  1330   a  and  1330   b . Two outputs of the analog baseband filter  1330   a  are passed to two switch units of  1340  and  1344 . In the same way, two outputs of the analog baseband filter  1330   b  are passed to the switch units of  1340  and  1344 . During the W-CDMA mode, two switches of  1342   a  and  1342   b  in the switch unit  1340  connect with the outputs from the analog baseband filters of  1330   a  and  1330   b . The output signals, a and b, of the switch unit  1340  are passed into a W-CDMA down converter and demodulation  1350 , which produces two analog baseband signals, g 1  and g 2 , for an A/D unit  1370 . During the UWB mode, two switches of  1346   a  and  1346   b  in the switch unit  1344  connect with the outputs from the analog baseband filters of  1330   a  and  1330   b . The output signals, c and d, of the switch unit  1344  are passed into an UWB multiband down converter and demodulation  1360  that generates eight analog baseband signals, u 1 , u 2 , u 3 , u 4 , u 5 , u 6 , u 7 , and u 8 , for an A/D unit  1370 . 
   Referring to  FIG. 14  is a detailed block diagram  1400  of the W-CDMA down converter and demodulation  1350  according to some embodiments. The input signals of a and b are summed together by using a W-CDMA sum over a block duration  1410 . The output signals of the W-CDMA sum over the block duration  1410  convert into two parallel signals that are demodulated with the multicarrier of  1420   a  and  1420   b , followed by two channel select filters of  1430   a  and  1430   b  to produce desired signals of g 1  and g 2 , respectively. 
   Referring to  FIG. 15  is a detailed block diagram  1500  of the UWB multiband down converter and demodulation  1360  according to some embodiments. The input signals of c and d are summed together by using an UWB sum over the block duration  1510  to produce four parallel signals for four multiband down converters and demodulations from  1520   a  to  1520   d . The multiband down converters and demodulations from  1520   a  to  1520   d  perform down converter and demodulation, and produce eight analog baseband signals from u 1  to u 8 . 
   Referring to  FIG. 16  is a detailed block diagram  1600  of the A/D unit  1370  according to some embodiments. There are two switch units of  1620  and  1640  and eight A/D converters from  1650   a  to  1650   h , with a sampling rate at 540 MHz. During the W-CDMA mode, two switches of  1620  and  1640  connect to the input signals of g 1  and g 2 , respectively. The outputs of the switches of  1610  and  1630  are passed into two A/D converters of  1650   a  and  1650   b , with the sampling rate at 540 MHz. This is 36 times oversampling for the W-CDMA signals. Other A/D converters from  1650   c  to  1650   h  are rest. The output signals au 1  and au 2  of the A/D converters of  1650   a  and  1650   b  will be used in the W-CDMA baseband processor. During the UWB mode, the switches of  1620  and  1640  connect to the input signals of u 1  and u 2 , respectively. The outputs of the switches of  1610  and  1630 , and input signals of u 3  to u 8  are in parallel passed onto eight A/D converters from  1650   a  to  1650   h , where the sampling rate is 540 MHz for all the A/D converters. The output signals of the A/D converters from  1650   a  to  1650   h  are referred to as au 1  to au 8 , which will be used in the UWB baseband processor. 
     FIG. 17  is a detailed block diagram  1700  of the W-CDMA baseband processor  1220  according to some embodiments. The input signals of au 1  and au 2  are passed through two digital filters of  1710   a  and  1710   b , followed by two down samplings of  1720   a  and  1720   b , respectively. The output signals of the down samplings of  1720   a  and  1720   b  are multiplexed by using a multiplexer (MUX)  1730 . Then, the output signal of the MUX  1730  is passed to a multiband rake receiver and decoder unit  1740  to produce a user data stream. 
   Referring to  FIG. 18  is a detailed block diagram  1800  of the multiband rake receiver and decoder unit  1740  according to some embodiments. The input signal is digitally demodulated to form  12  multiband baseband signals by using multipliers from  1810   a  to  1810   m . The 12 multiband baseband signals are passed through  12  digital filters from  1820   a  to  1820   m  to produce the desired signals, followed by using 12 despreader and rake units from  1830   a  to  1830   m . Then 12 parallel output signals of the despreader and rake units from  1830   a  to  1830   m  are multiplexed together by a MUX  1840  to produce a serial signal. The serial signal is thus despread by using a long code sequence that is generated by using a long code generator  1852  based on a long code users mask  1850 . The output signal of the despreader  1854  is deinterleaved by using a deinterleaver  1860 , followed by using a desymbol repetition  1870  and a decoder  1880  to produce the users data stream. 
     FIG. 19  is a detailed block diagram  1900  of the UWB OFDM multiband baseband processor  1230  according to some embodiments. The eight input signals from au 1  to au 8  are passed through a digital receiver filter unit  1910 , followed by a multiband dispreading unit  1920  and a TEQ unit  1930  to produce four parallel signals. The TEQ unit  1930  is used to reduce the length of cyclic prefix to a more manageable number without reducing performance significantly. In other words, the TEQ unit  1930  can produce a new target channel with a much smaller effective constraint length when concatenated with the channel. Thus, the outputs of the TEQ unit  1930  in parallel are passed through four S/Ps from  1940   a  to  1940   d  to produce parallel digital sequences. Each of the S/Ps from  1940   a  to  1940   d  produces 1280 parallel digital sequences for each of guard removing units from  1942   a  to  1942   d . The guard removing units from  1942   a  to  1942   d  remove 256 samples from the 1280 parallel digital sequences of the S/Ps of  1940   a  to  1940   d  to produce 1024 parallel digital sequences, which are used as inputs for FFT units from  1944   a  to  1944   d . Each of the FFT units from  1944   a  to  1944   d  produces 512 frequency-domain signals that are used for frequency-domain equalizer (FEQ) units from  1946   a  to  1946   d . The FEQ units from  1946   a  to  1946   d  are used to compensate for phase distortions, which are a result of phase offsets between the sampling clocks in the transmitter and the receiver of the MIMO-based multiband of the UWB communication transceiver. This is because the phases of the received outputs of the multiband FFT units from  1944   a  to  1944   d  are unlikely to be exactly the same as the phases of the transmitter symbols at the input to the IFFT units from  852   a  to  852   d  of the MIMO-based multiband of UWB base station transmitter as shown in  FIG. 8 . Thus, the outputs of the FEQ units from  1946   a  to  1946   d  are passed through a set of P/S units from  1948   a  to  1948   d  and a P/S  1950  to produce a serial sequence for all of the four frequency bands. Thus, the output sequence of the P/S  1950  is used for a despreading, deinterleaver, and decoding unit  1960 , which performs despreading, deinterleaving, and decoding for the MIMO-based multiband of the UWB mobile communication receiver. 
   Referring to  FIG. 20  is a detailed block diagram  2000  of a combination  1970  of the digital receiver filter unit  1910 , the multiband dispreading unit  1920 , and the TEQ unit  1930  according to some embodiments. The eight input signals from au 1  to au 8  are in parallel passed through the digital receiver filters from  2010   a   1  and  2010   a   2  to  2010   d   1  and  2010   d   2 , respectively. The output signals of the digital receiver filters from  2010   a   1  and  2010   a   2  to  2010   d   1  and  2010   d   2  are despread by using XORs from  2020   a   1  and  2020   a   2  to  2020   d   1  and  2020   d   2  with the output sequences of multiband dispreading from  2030   a  to  2030   d . Then, every pair of the output signals of the XOR from  2020   a   1  and  2020   a   2  to  2020   d   1  and  2020   d   2  are multiplexed together by using MUXs from  2040   a  to  2040   d , followed by using TEQ from  2050   a  to  2050   d.    
     FIG. 21  is a detailed block diagram  2100  of a combination  1980  including the FFT  1944  and the FEQ  1946  according to some embodiments. The FFT  1944  has a 1024-point input of real-value and produces a 512-point complex data labeled from 0 to 511, while a 512-point complex data with labels of labeled from 511 to 1023 is disable. The FFT  1944  labeled from 0 to 511 also contains 12 Nulls. So, the FFT  1944  produces a 500-point complex data for the FEQ  1946 . The FEQ  1946  contains 500 equalizers from  2110   a   1  to  2110   a   500  decision detectors from  2120   a   1  to  2120   a   500 , and 500 subtractions from  2130   a   1  to  2130   a   500  that operate in parallel. Each of the equalizers from  2110   a   1  to  2110   a   500  has N-tap with adaptive capability. Each of the decision detectors from  2120   a   1  to  2120   a   500  is a multi-level threshold decision. Each of the subtractions from  2130   a   1  to  2130   a   500  performs subtracting between the output of each of the equalizers from  2110   a   1  to  2110   a   500  and the output of each of the decision detectors from  2120   a   1  to  2120   a   500 . The output of each of the subtraction from  2130   a   1  to  2130   a   500  is referred to an error signal, which is used to adjust the N-tap coefficients of the each of the equalizers from  2110   a   1  to  2110   a   500  by using an adaptive algorithm  2130 . 
   The phases of the received outputs of the FFT  1944  do not have exactly the same as the phases of the transmitter symbols at the input to the IFFT units from  852   a  to  852   d  of the MIMO-based multiband of UWB base station transmitter as shown in  FIG. 8 . In addition, the phase responses have to consider the channel in which is coped with the TEQ  1930  as shown in  FIG. 19 . Thus, the FEQ  1946  in  FIG. 21  is used to compensate for the phase distortion that is a result of a phase offset between the sampling clocks in the transmitter and the receiver of the MIMO-based multiband of the UWB communication transceiver. The FEQ  1946  also offers the additional benefit of received signal scaling before decoding since the FEQ  1946  can be used to adjust the gain of the FFT  1944  output so that the decision detectors from  2120   a   1  to  2120   a   500  can be set the same parameters for all subchannels regardless of the different subchannel attenuations. 
     FIG. 22  is a detailed block diagram  2200  of the despreading, deinterleaver, and decoding unit  1960  according to some embodiments. This unit  1960  includes a despreading  2210 , a user-1 key  2220 , a deinterleaver  2230 , a Viterbi decoding  2240 , and a user-1 bitstream  2250 . The input signal is despread with a spreading sequence of the user-1 key  2220 , which provides a unique key sequence, by using the despreading  2210 . The despreading  2210  is a XOR operation to produce an encoded user-1 data bitstream. This encoded user-1 data bitstream is then deinterleaved by using the deinterleaver  2230  that is also coupled to the Viterbi decoding  2240 . The Viterbi decoding  2240  decodes the encoded user-1 data bitstream to produce an original transmitted user-1 data bitstream that is stored into the user-1 bitstream  2250 . 
   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. The following claims cover all such modifications and variations as fall within the true spirit and scope of the present invention.