ANALISA INTERFERENSI CDMA 2000 DENGAN EXTENDED GSM

ABSTRAKSI: Dalam perkembangan teknologi yang begitu cepat mengakibatkan perlunya regulasi frequensi yang ketat, sehingga memungkinkan diterapkannya frequensi yang berdekatan. Hal tersebut menyebabkan interferensi antar sistem, yang akan berdampak pada kualitas layanan telekomunikasi. Untuk itu perlunya perancangan jaringan yang lebih teliti untuk mengurangi interferensi antar sistem yang akan berakibat terganggunya kualitas jaringan. Di Indonesia, terutama pada daerah perbatasan negara terdapat permasalahan interferensi akibat penerapan CDMA 2000 1x dengan frequensi downlink 870,495-889,515 Mhz yang overlap dengan frequensi uplink Extended GSM 880-915 Mhz di negara tetangga. Pada tugas akhir ini dilakukan analisa pengaruh interferensi yang terjadi pada sistem CDMA 2000 yang disebabkan oleh Extended GSM. Beberapa scenario penelitian yang dilakukan antara lain pengaruh interferensi berdasarkan jarak antara base station CDMA dengan E-GSM, pengaruh interferensi berdasarakan jarak mobile station CDMA dengan Extended GSM dan pengaruh interferensi terhadap coverage CDMA. Berdasarkan hasil analisa pengaruh terbesar terdapat pada jarak antara MS CDMA dengan Extended GSM yaitu jika jarak kedua MS + 200 meter yang menyebabkan Eb/Io MS CDMA menjadi lebih kecil dari 7dB, dan pengaruh interferensi terhadap coverage CDMA yaitu nilai nilai Eb/Io akan stabil diatas 7 dB jika MS CDMA berjarak kurang dari 1 kilometer dari Base Station, dan jika lebih dari 1 kilometer nilai Eb/Io lebih kecil dari 7 dB.Kata Kunci : interferensi antar sistem, CDMA 2000, Extended GSMABSTRACT: The rapid technological developments resulting in the need for strict regulation of frequencies, thus enabling the implementation of the adjacent frequencies. This causes interference between system, which will impact on the quality of telecomunication services. Therefore the need for a more thorough network design to reduce interference bteween system that will result in disruption of network quality. In Indonesia, especially in border areas have problems of interference due to the application of CDMA 2000 1x with a downlink frequency of 870.495 to 889,515 MHz uplink frequency overlap with the Extended GSM 880-915 Mhz in neighboring countries. At this final duty conducted the analysis of interference effect that occurs in CDMA 2000 system caused by the Extended GSM. Some research scenario have done such as effect of distance Base Station CDMA and E-GSM, effect of distance Mobile Station CDMA with E-GSM, and position of base station in border. Based on result of analysis, the high effect of interference is a distance of Mobile Station CDMA and Extended GSM with the distance both Mobile Station + 200 meter due to the value Eb/Io less than 7dB. Effect interference of coverage CDMA is the value Eb/Io still stable more than 7 dB if the distance of Mobile Station CDMA less than 1 kilometer from Base Station and the value Eb/Io less than 7dB if the distance more than 1 kilometer.Keyword: inter-system interference, CDMA 2000, Extended GS

Generalized Spatial Modulation in Indoor Wireless Visible Light Communication

In this paper, we investigate the performance of generalized spatial modulation (GSM) in indoor wireless visible light communication (VLC) systems. GSM uses $N_t$ light emitting diodes (LED), but activates only $N_a$ of them at a given time. Spatial modulation and spatial multiplexing are special cases of GSM with $N_{a}=1$ and $N_{a}=N_t$, respectively. We first derive an analytical upper bound on the bit error rate (BER) for maximum likelihood (ML) detection of GSM in VLC systems. Analysis and simulation results show that the derived upper bound is very tight at medium to high signal-to-noise ratios (SNR). The channel gains and channel correlations influence the GSM performance such that the best BER is achieved at an optimum LED spacing. Also, for a fixed transmission efficiency, the performance of GSM in VLC improves as the half-power semi-angle of the LEDs is decreased. We then compare the performance of GSM in VLC systems with those of other MIMO schemes such as spatial multiplexing (SMP), space shift keying (SSK), generalized space shift keying (GSSK), and spatial modulation (SM). Analysis and simulation results show that GSM in VLC outperforms the other considered MIMO schemes at moderate to high SNRs; for example, for 8 bits per channel use, GSM outperforms SMP and GSSK by about 21 dB, and SM by about 10 dB at $10^{-4}$ BER

Forward-Backward Asymmetry as a Discovery Tool for Z' Bosons at the LHC

The Forward-Backward Asymmetry (AFB) in Z' physics is commonly only perceived as the observable which possibly allows one to interpret a Z' signal by distinguishing different models of such (heavy) spin-1 bosons. In this paper, we examine the potential of AFB in setting bounds on or even discovering a Z' boson at the Large Hadron Collider (LHC) and show that it might be a powerful tool for this purpose. We analyse two different scenarios: Z' bosons with a narrow and wide width, respectively. We find that, in the first case, the significance of the AFB search can be comparable with that of the bump search usually adopted by the experimental collaborations; however, being a ratio of (differential) cross sections the AFB has the advantage of reducing systematical errors. In the second case, the AFB search can win over the bump search in terms of event shape, as the structure of the AFB distribution as a function of the invariant mass of the reconstructed Z'boson could nail down the new broad resonance much better than the event counting strategy usually adopted in such cases.Comment: 27 pages, 17 figure

Generalized Spatial Modulation in Large-Scale Multiuser MIMO Systems

Generalized spatial modulation (GSM) uses $n_t$ transmit antenna elements but fewer transmit radio frequency (RF) chains, $n_{rf}$. Spatial modulation (SM) and spatial multiplexing are special cases of GSM with $n_{rf}=1$ and $n_{rf}=n_t$, respectively. In GSM, in addition to conveying information bits through $n_{rf}$ conventional modulation symbols (for example, QAM), the indices of the $n_{rf}$ active transmit antennas also convey information bits. In this paper, we investigate {\em GSM for large-scale multiuser MIMO communications on the uplink}. Our contributions in this paper include: ($i$) an average bit error probability (ABEP) analysis for maximum-likelihood detection in multiuser GSM-MIMO on the uplink, where we derive an upper bound on the ABEP, and ($ii$) low-complexity algorithms for GSM-MIMO signal detection and channel estimation at the base station receiver based on message passing. The analytical upper bounds on the ABEP are found to be tight at moderate to high signal-to-noise ratios (SNR). The proposed receiver algorithms are found to scale very well in complexity while achieving near-optimal performance in large dimensions. Simulation results show that, for the same spectral efficiency, multiuser GSM-MIMO can outperform multiuser SM-MIMO as well as conventional multiuser MIMO, by about 2 to 9 dB at a bit error rate of $10^{-3}$. Such SNR gains in GSM-MIMO compared to SM-MIMO and conventional MIMO can be attributed to the fact that, because of a larger number of spatial index bits, GSM-MIMO can use a lower-order QAM alphabet which is more power efficient.Comment: IEEE Trans. on Wireless Communications, accepte

Mobile Communication Networks and Digital Television Broadcasting Systems in the Same Frequency Bands – Advanced Co-Existence Scenarios

The increasing demand for wireless multimedia services provided by modern communication systems with stable services is a key feature of advanced markets. On the other hand, these systems can many times operate in a neighboring or in the same frequency bands. Therefore, numerous unwanted co-existence scenarios can occur. The aim of this paper is to summarize our results which were achieved during exploration and measurement of the co-existences between still used and upcoming mobile networks (from GSM to LTE) and digital terrestrial television broadcasting (DVB) systems. For all of these measurements and their evaluation universal measurement testbed has been proposed and used. Results presented in this paper are a significant part of our activities in work package WP5 in the ENIAC JU project “Agile RF Transceivers and Front-Ends for Future Smart Multi-Standard Communications Applications (ARTEMOS)”