Ultra-Wide Band Receiver

1. Ultra-Wide Band Receiver Outline Background Comparison with other wireless communication Architecture Blocks related to the corresponding digital communication theorem Development and application

2. Ultra-wide Band(UWB) Standards Bluetooth: 802.15 2.4 GHz 24 Mb/s WLAN: 802.11a 5 GHz 300 Mb/s UWB: 802.15.3a 3.1-10.6 GHz 1320 Mb/s • Federal Communications Commission(FCC)[1] opened the spectrum between 3.1 to 10.6 GHz for high data rate (1Gbps), short range (10m) with regulated a low power spectral density of -41.3dBm /MHz over the entire frequency range. • The proposed UWB system supports operation in two different bands: one band occupying the spectrum from 3.1 to 4.85 GHz (the low band), and the second band occupying the spectrum from 6.2 to 10.6 GHz (the high band). • The proposed UWB system employs direct sequence spreading of binary phase shift keying (BPSK) and quaternary bi-orthogonal keying (4BOK) UWB pulses.

3. Ultra-wide Band: MBOA standard • An UWB system has a fractional bandwidth greater than 20% or a minimum bandwidth greater than 500 MHz. According to the Shannon–Hartley theorem, the channel capacity of a properly encoded signal is proportional to the bandwidth of the channel. • MBOA (Multi-Band OFDM Alliance) UWB : The UWB signals are also based on orthogonal frequency division multiplexing (OFDM).

4. Ultra-wide Band • Conventional systems transmit information by varying the power level, frequency, and/or phase of a sinusoidal wave. UWB transmissions transmit information by generating radio energy at specific time intervals and occupying a large bandwidth, thus enabling pulse-position or time modulation • The pulses are very short, so most signal reflections do not overlap the original pulse and the multipath fading of narrowband signals does not exist. The short impulses less than 1ns are generated for wideband direct sequence spreading. (BPSK or 4BOK)

5. Hard ware Description A simplified transceiver block diagram employing a direct conversion Antenna Bandpass Filter and lowpass filter T/R Switch Low Noise Amplifier (LNA), Variable Gain Amplifier (VGA) and Power Amplifier (PA) Mixer and Synthesizer Analog Digital Converter (ADC) Digital Analog Converter (DAC) Processor (DSP-----digital signal processing)

6. Ultra-wide Band • Antenna (MIMO): • Coupling MIMO spatial multiplexing with UWB's high throughput gives the possibility of short-range networks with multi-gigabit rates. • The antenna must achieve almost a decade of impedance bandwidth, spanning 7.5 GHz. • The large group delay variation indicates large distortion and dispersion. • High radiation efficiency is imperative for an ultra wideband antenna . Any excessive loss incurred by the antenna could potentially compromise the functionality of the system.

7. Ultra-wide Band

8. Ultra-wide Band Bandpass Filter(BPF): Band Select Filter with a notched band in the UWB passband in order to avoid being interfered by the other radio signals. [4]

9. Ultra-wide Band Lowpass filter (LPF): A lowpass filter is required in wireless communication systems in order to suppress harmonics and spurious of power amplifiers and oscillators and to eliminate the outband noise T/R SW: Transmitter and receiver switch: High isolation, high linearity and power handling capacity

10. Ultra-wide Band Low Noise Amplifier (LNA) : The SNR required for a BER of 10−3for AWGN channel is over 10 dB. (Bit error rate (BER) corresponding to the bit error probability ) Variable Gain Amplifier (VGA): offer an adjustable gain and normalize the average amplitude of the signal to a reference value. Power Amplifier (PA): convert a low-power radio-frequency signal into a larger signal of significant power, typically for driving the antenna of a transmitter.

11. Ultra-wide Band • Mixer in direct conversion receiver (baseband to passband and pass band to baseband): • The multiple VCOs, which offers different carrier frequencies are needed for the multi-channel with wide band range. • Typically, keep the LO frequency = RF frequency + 5 MHz to achieve direct conversion, which is also different from other types of receiver.

12. Ultra-wide Band Mixer: Down/up convert the signal to the basband/passband.

13. Ultra-wide Band Analog Digital Converter (ADC): Sampling and Quantization (distortion) Digital Analog Converter (DAC): Modulation: (Converts digital data to a continuous waveform suitable for transmission)

14. Ultra-wide Band Mixer, synthesizer and VGA and ADC and DCA • IQ mixer are needed for the M-ray PSK modulation. (Quadraturesignal) • Synthesizer generates a stable center frequency by phase lock loop. • (Automatic Gain Control) Variable gain amplifier eliminates channel gain variations on selection of thresholds

15. Ultra-wide Band Processor (DSP): The most powerful part: all the digital stuff Source coding, channel coding and detection

16. Die photo • Filter, PA and T/R switch are off-chip component.

17. Development • When UWB was proposed, many big companies invest a lot of sources in this area. • UWB has a lot of advantages over the Bluetooth but it is proved failure. • Conflict between the Intel and Moto • High costs than what the market could accept • Application As the UWB is proved failure, the Intel proposed the WiGig for next generation and the frequency is over 60 GHz and data rate is 5 Gbps.

18. Reference • “First Report and Order, Revision of Part 15 of the Commission’s Rules Regarding Ultra Wideband Transmission Systems”, FCC, Washington, DC ET Docket 98-153, 2002. • “DS-UWB Physical Layer Submission to 802.15 Task Group3a”,http://www.uwbforum.org/ • “Multi-band OFDM Physical Layer Proposal for IEEE 802.15 Task Group 3a,” http://www.multibandofdm.org/ • G. M. Yang, R. Jin, C. Vittoria, V. G. Harris, and N. X. Sun, "Small ultra-wideband (UWB) bandpass filter with notched band," IEEE Microw. Wireless Compon. Lett., vol. 18, no. 3, pp. 176-178, Mar. 2008. • Q. Li and Y. P. Zhang, “CMOS T/R switch design: Towards ultra-wideband and higher frequency,” IEEE J. Solid-State Circuits, vol. 42, no.3, pp. 563–570, Mar. 2007.