A Rural Next Generation Network (R-NGN) and Its Testbed

Rural Next Generation Networks (R-NGN) technology allows Internet protocol (IP) based systems to be used in rural areas. This paper reports a testbed of R-NGN that uses low cost Ethernet radio links, combined with media gateways and a softswitch. The network consists of point-to-point IP Ethernet 2.4 GHz wireless link, IP switches and gateways in each community, standard copper wires and telephone sets for users. It uses low power consumption, and suitable for low density users. This combination allows low cost systems as well as multiservices (voice, data, and multimedia) for rural communications. An infrastructure has been deployed in two communities in Cipicung Girang, a village 10 km outside Bandung city, Indonesia. Two towers link the communities with a network of Institut Teknologi Bandung (ITB) campus. In addition, local wirelines connect community houses to the network. Currently there are four houses connected to each community node (for a total of eight house), upon which we can perform various tests and measurements

STUDI EKSPERIMEN UNJUK-KERJA MODULASI DBPSK PADA PLATFORM SOFTWARE-DEFINED RADIO (SDR)

ABTRACT This paper addresses Differential Binary Phase Shift Keying (DBPSK) modulation implemented on SDR platform for the development of digital data communications based on SDR. DBPSK modulation performance perceived at Packet Error Rate (PER) is evaluated in terms of Eb/No or S/N ratio, carrier frequency, bit rate, gain, roll-off factor of root Nyquist filter or root raised cosine filter, and of size of payload from delivered data. Based on this results, the smallest PER could be obtained by setting Eb/No value which is greater than 13 dB, carrier frequency of at least 0,3 MHz, optimum bit rate of 256 kbps, optimum range payload size of 2000 up to 4000 bytes, and roll-off factor of Nyquist or root-raised cosine filter of 0.1 < alfa < 0.9. INTISARI Makalah ini membahas pengujian unjuk-kerja modulasi Differential Binary Phase Shift Keying (DBPSK) yang diimplementasikan pada platform Software-Defined Radio (SDR) dalam rangka pengembangan sistem komunikasi digital berbasis SDR. Unjuk-kerja modulasi DBPSK diamati dalam bentuk Packet Error Rate (PER) dengan berbagai variasi nilai perbandingan Eb/No atau S/N, frekuensi pembawa, bit rate, gain, roll-off factor pada filter root Nyquist atau filter root raised cosine, dan ukuran payload data yang dikirimkan. Berdasarkan hasil penelitian ini, nilai PER terendah dapat diperoleh dengan mengatur nilai Eb/No lebih besar dari 13 dB, frekuensi pembawa minimal 0,3 MHz, bit rate optimum 256 kbps, ukuran payload optimum berkisar 2000 sampai dengan 4000 bytes, dan nilai roll-off factor pada filter Nyquist atau filter root-raised cosine adalah 0.1 < alfa < 0.9

Optimizing Low Speed VoIP Network for Rural Next Generation Network (R-NGN)

In this paper, we identify some impairments in the Voice over Internet Protocol (VoIP) networks and quantify the levels of voice quality. We propose an optimization model to maximize number of calls in low speed network for Rural Next Generation Network (R-NGN) while maintaining a minimum level of voice quality. The model is based-on Extended E-model to select parameters like voice coder, packet loss level, jitter buffer size, and network utilization. The optimum VoIP access network is achieved by applying G.723.1 5.3 kbps voice coder, packet loss level less than 1%, jitter buffer 50 ms, and network utilization less than 85%

UnoHop: Efficient Distributed Hash Table with O(1) Lookup Performance

Distributed Hash Tables (DHTs) with O(1) lookup performance strive to minimize the maintenance traffic required for disseminating membership changes information (events). These events dissemination allows each node in the peertopeer network maintains accurate routing tables with complete membership information. We present UnoHop, a novel DHT protocol with O(1) lookup performance. The protocol uses an efficient mechanism to distribute events through a dissemination tree that is constructed dynamically rooted at the node that detects the events. Our protocol produces symmetric bandwidth usage at all nodes while decreasing the events propagation delay

Empirical Mode Decomposition (EMD) Based Denoising Method for Heart Sound Signal and Its Performance Analysis

In this paper, a denoising method for heart sound signal based on empirical mode decomposition (EMD) is proposed. To evaluate the performance of the proposed method, extensive simulations are performed using synthetic normal and abnormal heart sound data corrupted with white, colored, exponential and alpha-stable noise under different SNR input values. The performance is evaluated in terms of signal-to-noise ratio (SNR), root mean square error (RMSE), and percent root mean square difference (PRD), and compared with wavelet transform (WT) and total variation (TV) denoising methods. The simulation results show that the proposed method outperforms two other methods in removing three types of noises

Experimental Study of DQPSK Modulation on SDR Platform

This Paper addresses Differential Quadriphase Shift Keying (DQPSK) modulation implemented on SDR platform for the development of digital data  communications based on Software-Defined Radio (SDR). DQPSK modulation performance perceived at Packet Error Rate (PER) is evaluated in terms of Eb/No or S/N ratio, carrier frequency, bit rate, gain, roll-off factor of root Nyquist filter or root raised cosine filter, and payload size from delivered data. Based on these results, the smallest PER could be obtained by setting Eb/No value greater than 20 dB, carrier frequency of at least 0,3 MHz, optimum bit rate of 200 kbps, optimum range payload size of 2000 up to 4000 bytes, and roll-off factor of Nyquist or root-raised cosine filter of 0.4

A Rural Next Generation Network (R-NGN) and Its Testbed

Rural Next Generation Networks (R-NGN) technology allows Internet protocol (IP) based systems to be used in rural areas. This paper reports a testbed of R-NGN that uses low cost Ethernet radio links, combined with media gateways and a softswitch. The network consists of point-to-point IP Ethernet 2.4 GHz wireless link, IP switches and gateways in each community, standard copper wires and telephone sets for users. It uses low power consumption, and suitable for low density users. This combination allows low cost systems as well as multiservices (voice, data, and multimedia) for rural communications. An infrastructure has been deployed in two communities in Cipicung Girang, a village 10 km outside Bandung city, Indonesia. Two towers link the communities with a network of Institut Teknologi Bandung (ITB) campus. In addition, local wirelines connect community houses to the network. Currently there are four houses connected to each community node (for a total of eight house), upon which we can perform various tests and measurements

An LPC Excitation Model using Wavelets

This paper presents a new model of linear predictive coding (LPC) excitation using wavelets for speech signals. The LPC excitation becomes a linear combination of a set of self- similar, orthonormal, band-pass signals with time localization and constant bandwidth in a logarithmic scale. Thus, the set of the coefficients in the linear combination represents the LPC excitation. The discrete wavelet transform (DWT) obtains the coefficients, having several asymmetrical and non-uniform distribution properties that are attractive for speech processing and compression. The properties include magnitude dependent sensitivity, scale dependent sensitivity, and limited frame length, which can be used for having low bit-rate speech. We show that eliminating 8.97% highest magnitude coefficients degrades speech quality down to 1.49dB SNR, while eliminating 27.51% lowest magnitude coefficient maintain speech quality at a level of 27.42 dB SNR. Furthermore eliminating 6.25% coefficients located at a scale associated with 175-630 Hz band severely degrades speech quality down to 4.20 dB SNR. Finally, our results show that optimal frame length for telephony applications is among 32, 64, or 128 samples

Application of Wavelet LPC Excitation Model for Speech Compression

This paper presents an application of linear predictive coding (LPC) excitation wavelet models for low bit- rate, high-quality speech compression.The compression scheme exploits the model properties, especially magnitude dependent sensitivity, scale dependent sensitivity, and limited frame length. We use the wavelet model in an open-loop dither based codebook scheme. With this approach, the compression yields a signal-to-noise ratio of at least 11 dB at rates of 5 kbit/s