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A new UWB signaling technique based on dual pulse transmission is presented in this paper. The proposed technique is simple, robust, and based on an autocorrelation type of receiver structure. Several detection schemes with different implementation complexity are presented and their performances are studied by Monte-Carlo simulations. Comparison of...
Citations
... Recently, authors in [7] proposed a frequency-shifted reference (FSR) scheme to keep away from the use of delay lines within the conventional TR machine. In [41], a dual pulse (DP) scheme proposed which are used contiguous pulses to transmit data and also only desires Tp long delay lines. due to closely spaced reference and information pulses the major problem of ISI and hence low performance in comparison to the traditional TR systems. ...
... due to closely spaced reference and information pulses the major problem of ISI and hence low performance in comparison to the traditional TR systems. It became proposed in [41] to mitigate IPI by using analog averaging over a couple of obtained DP frames before autocorrelation, or to completely take away IPI by using the IDP scheme. However, either solution required long delay lines as in the conventional TR scheme, except that in DP the frame period may be half the frame duration in TR, i.e., Tf, DP > Tm. ...
Ultra-Wide Band (UWB) technology due to its high speed, data rate and multipath immune characteristics is one of the promising solutions for communication systems. There have been awesome studies efforts to apply extremely-huge bandwidth using Ultra Wide band (UWB) technology to the military and government sectors. In UWB technology challenging task is synchronization and fine timing performance for the specified application. This paper explores the different types of UWB receivers which are Transmitted Reference (TR) UWB Receivers and Frequency Shifted Reference (FSR) UWB Receiver focusing on the synchronization and timing performance of the specified application. In order to identify these issues, the existing researches carried out in the domain of synchronization and timing performance of UWB from existing literatures. Through the review of existing literatures certain research gap are identified which are all stated in the research gap.
... In TR, the data rate is low because reference signals and data are sent simultaneously and it must also provide sufficient intervals between pulses when sending signals in order to avoid inter pulse interferences (IPI). In dual pulse (DP) [9], the reception performance is improved by sending the reference signals and data signals twice [10] and by transmitting signals as variants of DP [11]. The transmit reference pulse cluster (TRPC) method was recently proposed as an expanded DP method [12]. ...
... The IT1-R1 scheme is better than M-TRPC (N p = 16) by about 5.34 dB in CM2. In Fig. 10, the performances for coded SW [7], coded IT-SRAKE (IT2-R4, IT4-R4), coded DP [9], uncoded TRPC (N p = 12) and coded M-TRPC (N p = 16) are compared for CM2. This shows the performance of coherent scheme (SW, IT-SRAKE) and non-coherent scheme (DP, TRPC, M-TRPC). ...
... The performance of the two receiver schemes, IT-SRAKE and M-TRPC, are compared by considering target coded BER re- Fig. 10. BER performance comparisons of conventional-RAKE (SW) [7], IT-SRAKE, DP [9], TRPC [12], and M-TRPC in CM2. sults. ...
... Since this is not always the case, some other solutions were suggested. In [7] a new method for IPI cancelation, where every second reference pulse is inverted before the transmission, was proposed. Although that results in higher data rates, the main disadvantage of this solution is the high receiver complexity which then leads to the higher system cost. ...
One of the main drawbacks of conventional transmitted reference (TR) ultrawideband
systems is the fact that time delay between the reference and the data pulse has
to be at least equal to channel delay spread, in order to avoid inter-pulse interference (IPI).
This requirement drastically limits the achievable data rate of conventional TR systems
based on M-ary pulse position modulation (PPM). In this paper, the new method for M-ary
TR PPM scheme bandwidth efficiency increasing is proposed. In the proposed method the
orthogonal codes are used such that only the pulses which can cause IPI are coded. Usage
of such type of coding allows the reduction of time delay between the reference and the
data pulse, whereas IPI is avoided. The proposed method achieves higher bandwidth
efficiency than the conventional TR PPM method for the similar BEP performance level.
Furthermore, the results show that an additional increase in bandwidth efficiency can be
achieved by using higher modulation levels. Additionally, the analysis on tradeoffs between
the BEP performance, bandwidth reduction and system costs is given in this paper.
... In TR, the data rate is low because reference signals and data are sent simultaneously and it must also provide sufficient intervals between pulses when sending signals in order to avoid inter pulse interferences (IPI). In dual pulse (DP) [9], the reception performance is improved by sending the reference signals and data signals twice [10] and by transmitting signals as variants of DP [11]. The transmit reference pulse cluster (TRPC) method was recently proposed as an expanded DP method [12]. ...
... The IT1-R1 scheme is better than M-TRPC (N p = 16) by about 5.34 dB in CM2. In Fig. 10, the performances for coded SW [7], coded IT-SRAKE (IT2-R4, IT4-R4), coded DP [9], uncoded TRPC (N p = 12) and coded M-TRPC (N p = 16) are compared for CM2. This shows the performance of coherent scheme (SW, IT-SRAKE) and non-coherent scheme (DP, TRPC, M-TRPC). ...
... The performance of the two receiver schemes, IT-SRAKE and M-TRPC, are compared by considering target coded BER re- Fig. 10. BER performance comparisons of conventional-RAKE (SW) [7], IT-SRAKE, DP [9], TRPC [12], and M-TRPC in CM2. sults. ...
This paper presents new coherent and non-coherent detection methods for the IEEE 802.15.4a low-rate ultra-wideband physical layer with forward error correction (FEC) coding techniques. The coherent detection method involving channel estimation is based on the correlation characteristics of the preamble signal. A coherent receiver uses novel iterated selective-rake (IT-SRAKE) to detect 2-bit data in a non-line-of-sight channel. The non-coherent detection method that does not involve channel estimation employs a 2-bit data detection scheme using modified transmitted reference pulse cluster (M-TRPC) methods. To compare the two schemes, we have designed an IT-SRAKE receiver and a M-TRPC receiver using an IEEE 802.15.4a physical layer. Simulation results show the performance of IT-SRAKE is better than that of the M-TRPC by 3–9 dB.
... Mitigation techniques against CMI have been developed, for coherent and noncoherent receivers. TR schemes have been presented in [54], [55], which can cancel the IPI by combining two consecutive pulse pairs with so-called "balanced" data encoding. ...
The need for low-complexity devices with low-power consumption motivates the application of suboptimal noncoherent ultra-wideband (UWB) receivers. This article provides an overview of the state of the art of recent research activities in this field. It introduces energy detection and autocorrelation receiver front ends with a focus on architectures that perform the initial signal processing tasks in the analog domain, such that the receiver does not need to sample the UWB received signals at Nyquist rate. Common signaling and multiple access schemes are reviewed for both front ends. An elaborate section illustrates various performance tradeoffs to highlight preferred system choices. Practical issues are discussed, including, for low-data-rate schemes, the allowed power allocation per pulse according to the regulator's ruling and the estimated power consumption of a receiver chip. A large part is devoted to signal processing steps needed in a digital receiver. It starts with synchronization and time-of-arrival estimation schemes, introduces studies about the narrowband interference problem, and describes solutions for high-data-rate and multiple access communications. Drastic advantages concerning complexity and robustness justify the application of noncoherent UWB systems, particularly for low-data-rate systems.
... Besides , some of the proposals addressed the issue of inter-pulse interference (IPI) that arises when the separation between the pair of pulses is less than the delay spread [12]. To cancel out the IPI and also to increase the data rate with shorter inter-pulse distance, a dual pulse transmission scheme was proposed in [13]. Further, a balanced TR signaling scheme is designed that combines the dual pulse with M -ary orthogonal encoding [14], which aims to mitigate both the IPI and the multiple-access interference (MAI) by increasing the frame time without sacrificing the data rate. ...
A tractable and compact closed-form expression on the channel-averaged signal-to-interference-plus-noise ratio (SINR) is derived for M-ary orthogonal coded/balanced transmitted-reference (BTR) systems, taking into consideration both inter-pulse interference (IPI) and multiple-access interference (MAI) in dense multipath ultra-wideband (UWB) channels. The UWB channel here is a realistic and standard one with lognormal channel gain distribution and double independent Poisson arrival distribution of cluster and ray. Hence, the analytical framework developed here can be applied to typical UWB channel models, especially considering the channel sparseness and cluster overlapping observed in realistic UWB channels. Based on the channel-averaged SINR, the effect of inter-pulse distance (between the reference and data pulses in BTR) on the multiuser performance is fully investigated. A proper selection of user-specific inter-pulse distances in multiuser scenario is then determined to maximize the user capacity for a given UWB channel.
... For higher data rate, some literatures have been developed recently to permit small pulse spacing at the price of induced IPI at the receiver. A dual pulse detection technique is proposed in [5]. This technique is simple, robust, and based on a correlation type of receiver structure, but the detection performance still suffers from the IPI. ...
... This technique is simple, robust, and based on a correlation type of receiver structure, but the detection performance still suffers from the IPI. An improved technique is also introduced in [5] to obtain a clean template from interference-contaminated received signals by averaging signals over multiple symbol intervals. Nevertheless, it complicates the receiver much more compared to the previous one. ...
... Unfortunately, these filters might be hard to realize since they require estimation of the received waveform and long analog delay lines with high accuracy. Besides the analog approach to restrain the IPI, a digital signal processing model for TR system is put forward in [5]. The operation of template construction and complex detection requires a highsample-frequency analog-to-digital converter (ADC) and the receiver is no longer " simple " [4]. ...
A novel transmit-reference (TR) signaling scheme for UWB systems is proposed in this paper, where by invoking m-sequence codes the reference and data pulses are transmitted side by side to increase the data rate. This structure enables demodulation with a conventional correlation receiver despite existing server inter-pulse interference (IPI). For higher output SNR, an improved demodulation scheme is also introduced while adding little to the receiver complexity. Moreover, the proposed scheme can be extended to M-ary systems to further improve the data rate and power efficiency. Both analysis and simulations are performed to demonstrate the promising performance of the proposed scheme.
... Under the general block transmission framework which includes TR, ED, 1536-1276/08$25.00 c 2008 IEEE and differential UWB systems, the " dual pulse technique " of [1] can be thought of as a special case of block TR system with orthogonal codes of length two namely (+1,+1) and (+1,- 1). For clarity of exposition, we will consider the differential UWB system in detail. ...
... In this case, the data pulse is placed arbitrarily close to the reference one to increase the data rate. This approach was advocated in [1] under the term " dual pulse technique " and can be viewed as a special case of orthogonal codes we introduce later in this section. Before beginning the exposition, recall that Walsh-Hadamard spreading codes are rows of the Hadamard matrix [10, page 424] ...
Differential, transmitted reference (TR) and energy detection (ED) based ultra-wideband impulse radios (UWBIR) can collect the rich multipath energy offered by UWB channels with a low-complexity receiver. However, they perform satisfactorily only when the channel induced inter-pulse interference (IPI) is negligible. This can be achieved by appending a guard interval with duration greater than or equal to the channel's delay spread to each frame an operation limiting the maximum achievable data rate. As a remedy, this Letter advocates block transmissions in conjunction with orthogonal spreading sequences to remove the introduced IPI. The resultant scheme requires no channel knowledge besides timing offset and incurs slightly more complexity than non-block alternatives, while it increases the data rate at no cost in error performance. Given a fixed data rate of 25 Mbps, the novel block scheme exhibits about 1.8 dB gain relative to its non-block counterpart in single-user simulated tests.
... In [15], a dual pulse (DP) scheme that uses two contiguous pulses to transmit data was proposed. The delay between the reference and data pulses is then only a pulse width. ...
... In a TR or DP [15], [16] system, information is carried by a pulse pair in a frame: a reference pulse and a data pulse separated by T d seconds. To increase the signal-to-noise ratio (SNR) of the system, the same pulse pair is re-transmitted over N f frames. ...
... Large T d and T f lead to large delay lines which pose serious implementation challenges in practical UWB systems. The DP scheme proposed in [15] and [16] can be represented by (1) with T d = T p . Hence, the DP structure only requires short delay lines, but at the same time, suffers from IPI due to the compactly spaced pulses. ...
To meet the implementation constraint posed by ultra- wideband (UWB) delay lines, a new transmitted reference pulse cluster (TRPC) structure is proposed where a group of reference and data pulses with short uniform spacing is used for transmission. This structure enables a simple, robust, and practical autocorrelation detector to be implemented in the receiver. It overcomes the major hurdle to the practical implementation of conventional transmitted reference (TR) systems, i.e., the long-wideband-delay-line requirement. TRPC is also compatible with the signal format proposed within the IEEE 802.15.4a Working Group for coherent and noncoherent systems. The performance of the proposed TRPC receiver and noncoherent pulse-position modulation (NC-PPM) with energy detection are analyzed and compared. Simulation results show that TRPC outperforms the conventional TR, NC-PPM, the recently proposed dual-pulse scheme, and the frequency-shifted reference system. In particular, it achieves power saving over NC-PPM by about 1.3-1.9 dB for IEEE 802.15.4a channel model 1 and 1.3-2.3 dB for channel model 8.
... In [7], [8], the authors proposed a dual-pulse and an improved dual-pulse scheme for TR systems that essentially transmit a reference sub-pulse followed by a data sub-pulse as one pulse unit, which doubles the transmission rate when compared with the conventional TR UWB system. ...
This paper studies the performance of dual-pulse transmitted-reference (TR) ultra wideband (UWB) systems in presence of multi-access interference (MAI). We derive an analytical expression of the channel-averaged signal-to-interference ratio (SIR) for a TR UWB receiver in two asynchronous scenarios, based on random time-hopping (TH) codes. The analytical results and numerical results are presented for illustration. We further show the impact of the chosen system parameters (e.g. symbol duration and delay hopping code) to better understand their influence on the multi-user performance.
