A hybrid approach for UWB pulse shaping

Abstract

Ultra-wideband (UWB) technology offers a promising solution to the RF spectrum drought by allowing new services to coexist with current radio systems with minimal or no interference. This coexistence brings the advantage of avoiding the expensive spectrum licensing fees that providers of all other radio services must pay. In Ultra Wide Band technology, the conventional analog waveform is a simple pulse which in general is directly radiated to the air. These short pulses have typical widths of less than 1 nanosecond and thus bandwidth of over 1 GHz. Due to this wide bandwidth, Federal Communication Commission(FCC) has imposed certain restrictions on the emission limits of UWB systems. Inorder to fit well to the FCC mask, the basic pulse shapes have to be modified.So pulse shaping is very much relevant in UWB domain. The immediate objective of this paper is to design an optimal pulse shaping technique.This paper proposes a hybrid approach for UWB pulse shaping which utilises ideas from existing two techniques.

Performance Improvement of Ultra Wideband Multiple Access Modulation System using a new Optimal Pulse Shape

“…The obtained optimal pulse shows better results as compared to results presented in paper [12] by linearly combining two first-order derivatives of Gaussian pulses using different pulse shaping values of 0.049ns and 0.048ns . Also, the emission matching attained by our proposed method shows an improvement using the optimal pulse factor values for the first five Gaussian derivatives as compared to the same pulse factor value of 0.7 ns for the derivatives given in [20].…”

“…Another article [19] presented the pulse design technique based on linear combination of Gaussian doublet pulses and found that their proposed pulse, showed better spectral power efficiency as compared to other conventional pulse shapes. A new UWB pulse shaping method was also presented in [20] that divided the entire spectrum of UWB into different regions, and in each region the Gaussian pulse and its derivatives were combined, using least square error combination technique with same pulse shaping values. IEEE 802.15.3a Channel Model described in [7] [16] for Ultra wideband Indoor Communication.…”

An Efficient Method of Power Spectral Density Estimation for On-Chip IR-UWB Transmitter Self-Calibration

“…Indeed, as seen before, the instantaneous frequency gives the distribution of the energy along the frequency axis. But according to (22), the values of the envelopes gives the amount of energy. Thus, in order to reduce the contribution of these instantaneous frequency values, it is also possible to act on the envelope values.…”

“…Pulse design methods also exist based on the linear combination of the above-mentioned signals [18]- [20]. The superposition of Gaussian sub-carriers used in [21] and [22] enables flexibility for the realization of time domain pulse shapes in order to generate spectra which fits on FCC masks. The use of analytical pulse shapes allows to have a good knowledge on the spectrum but places a lot of constraints in the design of electronic devices required for the generation of such waveforms.…”

Improving ultra wideband (UWB) system by modified random combination of pulses

“…A pulse design technique based on the linear combination of Gaussian doublet pulses is presented in [12] and it was found that the proposed pulse showed better spectral power efficiency as compared to the conventional pulse shapes. A new UWB pulse shaping method has been presented in [13] [14] that divides the entire spectrum into regions and in each region the Gaussian pulse and its derivatives are combined using least square error combination techniques having same shaping factors in order to improve the spectral mask fitting. Research paper [15] illustrates direct sequence impulse UWB radio modulation systems.…”