factor frf deduction in ofdm ofdma cellular systems

... distribution in OFDM- based asynchronous cellular systems Ng N (OFDM symbol) G=S CP G CP (a) Conventional OFDM signal S (b) Proposed OFDM signal Figure 3: The concept of signal power reduction OFDM systems ... and β In this Section, we propose a novel resource allocation rule to increase β in multiuser OFDM systems such as OFDMA system and MC-CDMA system Unless all the resources (e.g., subcarriers in ... is inserted at the beginning of each OFDM symbol to mitigate the ISI and ICI due to the multipath delay spread in Jin-Woo Lee et al (m − 1)-th DFT window Signal m-th DFT window CP c-th OCI CP...

Ngày tải lên: 22/06/2014, 19:20

... interference mitigation in OFDM cellular systems Tho Le-Ngoc obtained his B.Eng degree (with distinction) in electrical engineering in 1976, his M.Eng degree in microprocessor applications in 1978 from ... low link outage Instead, reducing the probability of interference by using minimum bandwidth yields a higher protection against outage On the other hand, in a low shadowing scenario, as the minimum ... probability of interference is the dominant factor indicating the system performance in severe shadowing The advantage of the analytic model presented in this paper is that it can give insight into the...

Ngày tải lên: 22/06/2014, 22:20

... since relaying is increasingly wasteful of resources With fewer than hops, the addition of relays is slightly beneficial since the increase in SINR afforded by shortening the hop distances increases ... transmit beamforming methods Also, the use of MH relaying shortens the hop distances, which increases the SINR So although scattering is reduced, SINR is increased Increasing the SINR provides higher ... multiplexing provides the greatest capacity gains at high SINR; however, cellular systems typically operate at low SINR, with users at cell edges suffering from the poorest SINR Multihop relaying...

Ngày tải lên: 21/06/2014, 01:20

... one RS-to-BS link Therefore, there are total 2N + links in this system, i.e., one MS-to-BS link, N MS-toRS links, and N RS-to-BS links Assume all the link gains undergo mutually independent non-identical ... 710071, China 3Computer Science and Engineering Department, Hong Kong University of Science and Technology, Jiulong, Hongkong 999077, China College of Electronic and Information Engineering, Nanjing ... Nanjing 210016, China 5National Mobile Communications Research Laboratory, Southeast University, Nanjing 210096, China Competing interests The authors declare that they have no competing interests...

Ngày tải lên: 21/06/2014, 02:20

... symbols minimizing the frequency-domain channel estimate MSE and are in general more preferable than pilot symbols minimizing the time-domain channel estimate MSE Pilot symbols minimizing the ... state information; IDFT: inverse discrete Fourier transform; ISI: inter-symbol interference; LMI: linear matrix inequality; MMSE: minimum mean-squared error; MSE: mean-squared errors; OFDM: orthogonal ... minimizes h2 in (23) or h∞ in (25) under the constraint (26) We first consider the minimization h2 The optimal power distribution can be obtained by minimizing the squared h in (23) with respect to...

Ngày tải lên: 21/06/2014, 03:20

... very small training overhead requirement 14 EURASIP Journal on Advances in Signal Processing Conclusion In this paper, we have proposed training-based compensation schemes for OFDM systems impaired ... these lead to ill-conditioning in (45) N p shows that as the number of training symbols is increased, we also have additional tone pairs that can be included in (45), leading to an improved estimation ... accurately known, we can obtain Stot [l] as in (12) This is the principle behind the joint compensation scheme in [11, 17] It should be noted that (14) is also valid in the presence of either only...

Ngày tải lên: 21/06/2014, 08:20

... for multiuser OFDM cognitive radio systems, ” in Proceedings of the 2nd International Conference on Communications and Networking in China (ChinaCom ’07), pp 115–119, Shanghai, China, August 2007 ... in Section and the main findings are summarized in Section System Model We consider the problem of allocating resources on the downlink of an MU -OFDM CR system with one base station (BS) serving ... unconstrained binary quadratic programming problem,” BioSystems, vol 78, no 1−3, pp 99–118, 2004 [27] P Merz, “On the performance of memetic algorithms in combinatorial optimization,” in Proceedings...

Ngày tải lên: 21/06/2014, 11:20

... principle structure of PTS method is shown in Figure as that in [15] In PTS approach, the input data block is partitioned into disjoint subblocks Each subblock is multiplied by a phase weighting ... clusters, the phase weighting factor can be chosen from a larger set of {2, 4, 8, 16} It is shown that the added degree of freedom in choosing the combining phase weighting factors provides an additional ... reduction for OFDM using PSO with acceleration factors c1 and c2 when N = 128, M = 4, and W = It can be seen that when the acceleration factors increases resulted in the PAPR depression increasing For...

Ngày tải lên: 21/06/2014, 23:20

... will bring insight into the structure of the optimal array, which can be to some extent generalized to a mobile scenario In fact, in mobile systems or in case the position of users and interferers ... setting A According to both optimization criteria, the optimal array has external spacing Δ12 1.26 λ and internal spacing Δ23 3.6 λ It is interesting to compare this result with the case of a line-of-sight ... antenna spacings Δ through nonlinear relationships The first problem we tackle is that of finding the set of optimal spacings Δ that minimizes the average (with respect to fading) interference...

Ngày tải lên: 22/06/2014, 19:20

... get SINRb for the bth frequency subband The SINR margin value for each subband is calculated as SINRmargin,b = SINRb − SINRthreshold (14) We pick a subband b with the largest SINR margin value ... base station has all channel information about mobile terminals In real systems, such information can be achieved by channel estimation [12] In the frequency domain, the channel response is represented ... extended to OFDM systems These algorithms are described in an increasing order of complexity as Random-Fit, First-Fit, and Best-Fit To facilitate the algorithm description, the following definitions...

Ngày tải lên: 22/06/2014, 19:20

... potential for increasing the multiuser diversity in multiple access has resulted in an extension of the algorithm to OFDMA [24] A low-complexity implementation of the OSSA in OFDMA includes initial ... Networking basis of Campello’s conditions [5] providing implementation of the water-filling principle in practical systems For example, a practical bit loading algorithm has been derived in [7], ... water filling Generally, such power loading may result in ineffective use of the transmit power since it is primarily used for compensation of deep fading and according to the lemma a power gain is...

Ngày tải lên: 22/06/2014, 19:20

... The main steps in obtaining (12) are outlined in the appendix As vI and τ are integers, the estimation range of the normalized IFO vI is in [0, N − 1] and the search range of timing τ is in [0, ... Chengdu, China, in 1994 and the M.S degree from the Guilin University of Electronic Technology, Guilin, China, in 2002 He received the Ph.D degree in information and communication engineering from ... degree in electronic engineering from Guilin University of Electronic Technology, Guilin, in 1986, and the M.S and Ph.D degrees in electronic engineering from Xidian University, Xi’an, in 1992...

Ngày tải lên: 22/06/2014, 22:20

... Although we are merely interested in system level results we include fast (instantaneous) fading properties in our investigations Fast fading is analytically included in the calculation of the SIR ... quasi time-invariant within the period of interest The kth ˆ user uplink signal sk (t) includes the complete baseband signal processing as channel encoding, data modulation, and ˆ spreading in case ... capacity of the system increases when adopting power control since intracell interference is reduced However, intercell interference is only marginally affected by power control Finally, no handover...

Ngày tải lên: 23/06/2014, 01:20

... transmitted power during the K probings Inserting (43) into (42), we obtain that in the case of using optimal orthogonal weighting matrices, the expression for optimal weighting coefficients can ... condition on optimal probing matrices Using (36), we obtain that in the optimal probing case, W Since tr{Rh } > 0, we see from (26) that JSLS is a monotonically increasing function of JLS Note ... one can compensate for this effect by increasing the total transmitted power in the probing mode Another interesting observation is that the error in (23) is independent of the channel realization...

Ngày tải lên: 23/06/2014, 01:20

... processing to acquire the time-domain complex envelope for each experiment is the following First, the digital oscilloscope acquires the input and output signals using Modeling Nonlinear HPA in OFDM ... those defining the boundaries partitioning the input space: αi and βi ; those defining the linear combination of the model components: a, B, and ci ; and the smoothing parameter γ The training algorithm ... was born in Vitoria, ı Spain in 1967 He received his Telecommunication Engineer degree and his Ph.D degree in electrical engineering from the Polytechnic University of Madrid, Spain in 1991 and...

Ngày tải lên: 23/06/2014, 01:20

... Engineering Steering Group Internet Engineering Task Force Intra or Inter Frequency Handover Internet Key Exchange Instant Messaging Inverse Multiplexing for ATM IP Multimedia Subsystem International ... M-payments, m-banking, m-booking, m-brokering, m-ticketing Proximity services Push to talk over cellular (PoC) Presence Conferencing Instant messaging It is becoming increasingly evident that ... Internet Assigned Numbers Authority IMS Charging Identifier Internet Control Message Protocol Identity Information Element Institute of Electrical and Electronic Engineering Internet Engineering...

Ngày tải lên: 27/10/2014, 01:04

... constituting an interconnected network of struts or plates Many of these newer foams are increasingly used for insulation, as cushioning, and in systems for absorbing kinetic energy in impacts Cellular ... (2-3) (a) Unplated ring chain (b) Plated ring chain Fig 2-9 Ring chains used in the experiments conducted by S R Reid et al [12] Table 2-1 Elastic wave speeds in mild steel ring chains (D =50.8 mm, ... rings under lateral loading, the response of a ring under impact loading and the stress wave velocities through single rings are determined 3.3.1 Compression Tests on a Single Ring To determine...

Ngày tải lên: 05/10/2015, 19:03

... on outgoing calls and on roaming situations Placing restrictions on roaming could be useful in several cases, such as avoid expensive charging for forwarded incoming calls for MS roaming abroad ... Management 3.3.4.1 Paging Paging is used to determine the position of a MS The service area of an MTX can be divided into a number of traffic areas Paging involves sending over all CCs in the traffic area ... containing system parameters † Event The message received in Event provides the MS with information that is needed in order to update information that was received in possible previous initializations...

Ngày tải lên: 29/09/2013, 21:20

... (at least in the context of IP) to obtaining an IP address After setting up a PDP context, the mobile can then begin using GPRS point-to-point or point-to-multipoint services GPRS maintains the ... stream is then interleaved randomly by the interleaver (at an interval of 20 ms) into frames (frame interleaving) The purpose of using interleaving is to combat the multipath fading environment, ... 4.5.3 Automatic Roaming Automatic roaming allows a roaming user to originate a call inside the visited system after credit worthiness has been validated, to invoke in the visited systems the subscribed...

Ngày tải lên: 29/09/2013, 21:20

... (3G) Cellular Systems 161 infrastructures combining high capacities in the downlink with low capacities in the uplink Multimedia news broadcasting, interactive games and location-based information ... Multiple-switching-point configuration (asymmetric downlink/uplink allocation) Figure 5.17 Single-switching-point configuration (symmetric downlink/uplink allocation) Figure 5.18 Single-switching-point configuration ... downlink/uplink allocation) frames is the same, however, TDD frames contain switching points for uplink/downlink traffic separation The ratio of uplink/downlink slots within a frame can vary in...

Ngày tải lên: 29/09/2013, 21:20