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The paper investigates chirp pulse compression as a signal dimension reduction technique in non-coherent impulse-radio ultra-wideband (IR-UWB) communications. Two common types of non-coherent IR-UWB detection are considered, energy detection of IR-UWB pulse position modulated (PPM) symbols and sample-wise differential detection of differential phase shift keying (DPSK) IR-UWB symbols, as well as a newly introduced sample-wise differential detection of IR-UWB PPM symbols. A common problem with these low-complexity IR-UWB detection schemes is poor performance when the dimension of the symbol in detection is high, which is usually the case at low data rates and is especially pronounced in interference environments. Chirp pulse compression mitigates this problem by reducing the dimension of the symbol in detection along with very small fading factor, which also lowers the computational complexity in the case of digital implementation. In the analytic part of the paper, we develop a closed-form expression for the bandwidth and dimension of the signal after the chirp pulse compression, which was lacking before. Furthermore, a closed-form expression of the bit error probability in white noise with the above detection schemes is also given. In the numerical part of the paper, we compare the performance with and without chirp pulse compression of the above modulation/detection pairs in noise and interference environments.

The paper analyses performances of the two lowest data rates of impulse-radio ultra-wideband DPSK physical layer of recently published IEEE 802.15.6 Body Area Networks standard. Two receiver architectures suitable for the reception of symbols with signal structure described in specification of this physical layer, namely duty-cycled sampling receiver and chirp receiver, are introduced. Then, performance of these receiver architectures are analyzed through probabilities of error in different phases of packet reception. Analysis has been performed in the presence of different types of interference; namely frequency modulated ultra-wideband, WiMax and other co-located IEEE 802.15.6 impulse-radio ultra-wideband devices.

This paper describes the Impulse Radio Ultra-Wideband (IR-UWB) system using linear chirp UWB pulses as symbols. The novel method of coherent or differentially coherent detection of chirp pulses in multipath channels is introduced. The method divides detection in the receiver between its analog and digital part; in the analog part of the receiver, received signal is compressed in frequency by mixing with locally generated chirp pulse and low-pass filtering. In this way, the time-bandwidth (TB) product of the resulting signal is reduced compared to the received signal and made approximately independent of duration of the transmitted signal. This results in relatively low complexity digital back-end of the receiver that is able to capture a large portion of the multipath energy, regardless of duration of the transmitted waveform. The work includes derivation of analytical properties of the system, including derivation of loss parameters that quantify system multipath performance. Numerical results include discussion on the system multipath loss performance with varying chirp duration. As well, a comparison is made with error performance of sampling receivers featuring the same computational complexity. Analysis of the robustness of the system's performance to different chirp pulse implementation errors is also provided.

In this paper, a method for the design of nonlinear phase, full-band, ultra-wideband (UWB) pulses that satisfy the Federal Communications Commission's effective isotropic radiation power spectrum mask, or more generally, any other given mask, is introduced. The method uses convex programming in each step of the iterative procedure that updates the phase distribution of the goal function. Thanks to its mathematical structure, this method can be easily modified in order to be applied, in sequential fashion, to several different orthogonal UWB pulse-design problems, addressed later in the paper. The first among them is a problem considered in literature-design of multiple pulses, orthogonal when radiated. When employed for solving this problem, the method proposed here produces a considerably larger number of orthogonal pulses with high energy compared to the methods introduced before. As a novelty, the problem of designing pulses which are orthogonal in reception is considered. Then, a modification of our method is presented that can be used to solve this problem. We also introduce statistical criteria of robustness of pulses' orthogonality in reception, to the variation of the pulses' shape caused by the channel transfer function. After that, a modification of the proposed method is presented that is capable of producing a set of pulses with predefined maximum value of this criteria. Furthermore, it is shown that the method proposed can be used to efficiently design orthogonal pulses using a suboptimal value of the sample rate. All the concepts introduced are illustrated by design examples

The paper presents methodology for analyzing compliance of Impulse Radio Ultra-Wideband (IR-UWB) communications systems with regulatory limits specified by US Federal Communications Commission (FCC). First, discrete spectral component that reduce Effective Isotropic Radiated Power (EIRP) in IR-UWB spectrum are analyzed in an exemplary IRUWB system. After that, a minimal Pulse Repetition Frequency (PRF) in an IR-UWB system at which EIRP spectrum level does not have to be reduced in order to meet peek power regulatory constrain is derived for two different modulations; namely, On-Off Keying (OOK) and Binary Phase Shift Keying (BPSK).

The paper analyses several modulation and detection pairs for Impulse-Radio Ultra-Wideband (IR-UWB) Body Area Networks (BANs). First, transceiver architectures with and without chirp pulse compression are described. After that, exact expressions for the bit error probabilities in noise are given. At the end, numerical analysis is performed that includes performances in noise and performances in multiple access interference, which are especially critical for medical IR-UWB BANs.

The paper introduces an efficiency factor useful for the pattern synthesis of the transmitting antenna arrays with each array element being fed by its own power amplifier, active power of which is limited. The factor is based on the L ∞ norm of the active powers at the elements' feeds with mutual coupling between elements taken into account. Two Second Order Cone Programming (SOCP) based methods of the array radiation pattern synthesis that maximize this factor are formulated. After that, minimax array radiation pattern synthesis method with this factor constrained is described. As an illustration of its features, the method is applied on the pattern synthesis of a 15-element antenna array model obtained from the method of moments EM simulation.

The paper proposes a novel Trellis Coded Modulation (TCM) scheme for coherent Impulse-Radio Ultra-Wideband (IR-UWB) IEEE 802.15.4a communications that, in comparison with the current IEEE 802.15.4a IR-UWB communications scheme, is able to reduce energy per bit consumed in the receiver two times with approximately 2 dB performance loss. Furthermore, changed in the IEEE 802.15.4a coherent IR-UWB radio required to implement proposed TCM are minimal. Downside is that the proposed TCM scheme cannot be detected by non-coherent receivers. Discussion starts by looking at the current IEEE 802.15.4a IR-UWB coding and modulation scheme as a rudimentary TCM. After that, a transition is made through the TCM framework from the current IEEE 802.15.4a IR-UWB coding and modulation scheme to the proposed one.

In this paper, we propose a novel type of Impulse Radio Ultra-Wideband (IR-UWB) beamforming structure that we named a chirp beamformer. It represents an alternative to the well-known correlation beamforming paradigm. The chirp beamformer uses a chirp pulse as a symbol waveform. In comparison with a correlation beamformer, the chirp beamformer requires considerably lower timing resolution in cases where the IR-UWB symbol consists of a relatively long single uninterrupted waveform, as in the mandatory modes of two of the IEEE 802.15 IR-UWB standards, namely IEEE 802.15.4a-2007 and IEEE 802.15.6-2012. Furthermore, the bandwidth of the signal that the chirp beamformer generates in the baseband is considerably lower than in the case of the correlation beamformer. Hence, in the case of digital baseband signal generation, the chirp beamformer requires a considerably lower sampling rate than the correlation beamformer. A method for shaping the beam pattern of the chirp beamformer is also described. All concepts introduced are illustrated by numerical examples.

In this paper we present analysis of the physical layer performance of an system with the On-Off Keying (OOK) modulation. We begin with developing a system model with describing three different receiver architectures; namely, coherent quadrature sampling receiver, envelope sampling receiver and energy detection receiver. Performances of these receiver architectures are compared in noise and Multiple Access Interference (MAI). Furthermore, the performance comparison is made in three different phases of the packet reception: preamble synchronization, Synchronization Frame Delimiter (SFD) detection and payload detection.

This paper investigates possible amendment of the IEEE 802.15.6 standard for Body Area Network (BAN). Particularly, we study amending the IEEE 802.15.6 Impulse-Radio Ultra-Wideband (IR-UWB) DPSK Physical Layer (PHY) through adding data rates lower than what is currently both the lowest and mandatory data rate of this PHY. The motivation for this study is enhancing link margin and, more importantly, enhancing PHY's multi-BAN interference resistivity, crucial in medical applications of IEEE 802.15.6 BAN. Three different possibilities of adding lower data rates are considered. The first is increasing transmitted waveform duration and thus symbol rate; the second is introducing a spreading sequence and using current mandatory data rate symbols as chips; the third is introducing an inner convolution code for concatenation with the existing BCH(63,51) block code. Performances of these communication schemes are studied in multi-BAN interference.

The paper describes technique for differential detection of Impulse Radio Ultra-Wideband (IR-UWB) Pulse Position Modulated (PPM) symbols. An expression for probability of error in noise is derived. The numerical results show the method's performance enhancement compared to the energy detection in noise and considerable performance enhancement in multiuser interference. The method is applicable to the mandatory mode of the IEEE 802.15.6 Body Area Network (BAN) IR-UWB standard.

The paper analyses performances of the mandatory mode of Body Area Network IEEE 802.15.6 Impulse-Radio Ultra-Wideband DPSK physical layer in different types of interference; namely Frequency Modulated Ultra-Wideband, WiMax and other co-located IEEE 802.15.6 Impulse-Radio Ultra-Wideband devices. Interference performance of two receiver architectures suitable for the specification of this physical layer: duty-cycled sampling receiver and chirp receiver are analyzed through probabilities of error in different phases of packet reception.

In this work differentially coherent communication schemes for Impulse Radio Ultra-Wideband (IR-UWB) that transmit single uninterrupted package of energy per symbol, expected to be included in the IR-UWB IEEE 802.15.6 wireless Body Area Networks (BAN) standard are considered. Models for two receiver architectures, suitable for such communication schemes and feasible to implement in current CMOS technology — duty-cycled sampling receiver and chirp receiver are derived. After that, two differential detection techniques for employed receiver architectures — ordinary DPSK and Sample-wise DPSK (S-DPSK) are described. Theoretical analysis of probability of error for S-DPSK is also provided. Performances of the sampling and the chirp receiver architectures with DPSK and S-DPSK detection methods employed are analyzed under narrowband and Frequency-Modulated UWB (FM-UWB) types of interference.

In this paper, several aspects of IEEE 802.15.6 DPSK IR-UWB physical layer for usage in the medical BAN are examined. First, the types of the waveforms used in the standard are given. After that we describe the packet structure. We also provide mathematical analysis of two receiver structures: the duty-cycled sampling receiver and the chirp receiver is provided with suitable digital detection methods definitions and analysis. The paper continues with developing a method of synchronisation for preamble structure described in the standard draft together with the synchronisation frame delimiter (SFD) detection method. Preamble structure itself is discussed together with offering an alternative that has better performance with less computational complexity. The performances of receivers designed according to specifications given in the paper are simulated in multi-BAN environments in order to verify robustness of such BAN devices to interference from co-located BANs, essential for the application of this physical layer in the medical BAN.

A novel approach to arbitrary array pattern synthesis is proposed. It is based on the minimax algorithm originally developed for mismatched filter design for radars with pulse compression. The proposed approach allows the user to define the pattern mainlobe beam width and the sidelobe envelope shape.