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... Wireless Communications Wireless Communications in Business Objectives • List the advantages of wireless communications for businesses • Discuss the challenges of wireless communications ... staff 10 Summary • Wireless technology can positively impact an organization in many ways • Wireless technology faces various challenges • Once a business has decided to invest in wireless technology ... by Cisco in 2001 showed that – By using a WLAN, employees could access data almost two additional hours each day Increased Access to the Customer’s Own Data • Key factor in reducing business costs

Ngày tải lên: 13/09/2012, 11:16

... maintain the radio link. Advanced Trends in Wireless Communications 26 ─ Attenuation 5 dB threshold + Shadowing beginning 0 Shadowing cluster beginning Time (min) Attenuation ... frame. After coding, the obtained data are scrambled using an 8 bytes scrambling sequence. The scrambling sequence is chosen in order to provide at the Advanced Trends in Wireless Communications ... is pointing towards the Tx antenna. As one can observe in Fig. 4, the comparison of the Advanced Trends in Wireless Communications 28 power distribution in the environment, obtained with

Ngày tải lên: 19/06/2014, 23:20

... this link length is of the magnitude of ± 1 g/m3 In the case of an 11.05 km link, the uncertainty in evaluating the attenuation is ± 0.01 dB/km, hence the corresponding error in calculating the ... which is determined by the quality of its initial conditions or forcing data Humidity, in particular, is a critical variable in the initialization of these models The Mesoscale Alpine Programme ... operating in real time with minimum supervision, and therefore can be considered as continuous, high resolution humidity observation apparatus Environmental monitoring using data from wireless

Ngày tải lên: 19/06/2014, 23:20

... avoid mutual interference: S1 transmits in time-slot 1 (solid lines), S2 in time-slot 2 (dashed lines), R1 in time-slot 3 (dotted lines), and R2 in. .. (Zhang, 2008) In fact, in (Zhang, ... directly determines the diversity gain over fully-interleaved fading channels (Proakis, 2000, Ch 8), (Simon & Alouini, 2000, Ch 12) In UEP linear codes,... France 1 Introduction Wireless networked ... Advanced Trends in Wireless Communications networks as the blueprint Furthermore, in contrast to routing, this problem is crucial in NC due to the algebraic... methods Finally, Section

Ngày tải lên: 19/06/2014, 23:20

... are summarized in Table 1 In particular, wenotice that errors occur if and only if there is a decoding error over a single wireless link On the other hand, if errors occur in both links they cancel ... S2from the APEPs computed in Section 5.3.2 By taking into accountthat the wireless links are i.i.d and that the average error probability over a single-hop link isgiven by ¯P in (11), from (20), (30)-(33), ... of coding over routing in a randomized setting, Proceedings of IEEE ISIT, Yokohama, Japan, p 442. Ho T et al (year 2006), A random linear network coding approach to multicast, IEEE Trans. Inform

Ngày tải lên: 19/06/2014, 23:20

... on the precoding system performance, (b) Behavior of the precoding system of different block lengths Also, increasing the block length will increase the intersymbol interference inside the block ... system is shown in Fig 13 and given in the Eq 29 In order Fig 13 Variance distribution in the precoding system The main idea proposed here is to split the precoding process given in Section 4 between ... concern In these systems, one can accept some processing in the receiver in order to increase the performance of the system A sharing strategy between the transmitter and the receiver for the downlink

Ngày tải lên: 19/06/2014, 23:20

... processing Single-input single-output (SISO) is the well-known wireless configuration, single-input multiple-output (SIMO) uses a single transmit antenna and multiple receive antennas, multiple-input ... performance using adaptive frequency hopping, Proceeding of 4th IEEE International Conference on Wireless Communications, Networking and Mobile Computing, Dalian, China, Oct 2008 Zander, J & Malmgren, ... to mitigate fading in wireless links, so diversity is often used to combat fading Diversity techniques rely on transmitting the signal over multiple (ideally) independently fading paths over

Ngày tải lên: 19/06/2014, 23:20

... systemtakes into account the effects of the antennas and the propagation channel including the pathloss In contrast to the pulse signal, the spectrum of a TR signal has a descending shape withincreasing ... Akogun, A E., Qiu, R C & Guo, N (2005) Demonstrating time reversal in ultra-wideband communications using time domain measurements, International Instrumentation Symposium. Edelmann, G., Akal, ... Consumer Communications and Networking Conference, CCNC2007, pp 629–633. Naqvi, I & El Zein, G (2008) Time domain measurements for a time reversal SIMO system in reverberation chamber and in an indoor

Ngày tải lên: 19/06/2014, 23:20

... relating RSSI values can be made off-line Using a look-up table eliminates the need of estimating distances but introduces interpolating errors which for high distances can become unpractical In ... (2007) RFID indoor positioning based on probabilistic RFID map and Kalman filtering Proceedings of 3rd IEEE International Conference on Wireless and Mobile Computing, Networking and Communications ... access to information services in a mobile environment The use of small disjoint geographical connectivity areas in SIC networks is translated into a significant increase in cell (or per information

Ngày tải lên: 19/06/2014, 23:20

... (Qingchong, 2005) Finally, this type of technology as opposed to radio links, does not require licensing in addition to not cause interference 2.1 Applications of the OWC systems Optical wireless ... Several problems arise in optical wireless communications because of the wavelengths used in this type of system (Osche, 2002) The main processes affecting the propagation in the atmosphere of ... turbulence effects include fluctuations in the amplitude and phase of the optical signal (Tatarski, 1970), (Wheelon, 2003) The turbulence-induced fading in optical wireless communication links is similar

Ngày tải lên: 19/06/2014, 23:20

... researchers Informed consent for all informants was obtained prior to the beginning of the interview The selection of informants in the qualitative component was purposeful and intentional, aiming to ... regarding contracts Preference of health unit personnel regarding contracts % Basic health unit personnel Total Physicians Nurses Others Maintain indefinitely 17 21 22 13 Maintain until finding ... positive relation obtained between investment and productivity diminishes the possibility of increasing the investment to improve workers' labour conditions Increasing economic incentives, medical...

Ngày tải lên: 18/06/2014, 17:20

... 2011 Printed in Croatia A free online edition of this book is available at www.intechopen.com Additional hard copies can be obtained from orders@intechweb.org Recent Advances in Wireless Communications ... Modified CRLB During the process of deriving the HCRB, an important step involves taking the inverse of the Fisher’s information matrix In some cases, the inverse of the Fisher‘s information matrix ... research Finally, Part C consists of seven chapters that are devoted to applications and realizations Chapter is an introduction to topics at an inner receiver in wireless communications, including...

Ngày tải lên: 19/06/2014, 19:20

... higher in multicarrier communications than in single carrier communications because of intersymbol interference The mismatch or instability of the local oscillator inevitably causes an offset in ... tracked time-varying symbol timing offset, which results in time-varying phase changes Intercarrier interference comes into being another attached problem Because an error in the sampling frequency ... frequencies In this block, orthogonality in subcarriers is introduced In IFFT, the frequency domain OFDM symbols are converted into time domain OFDM symbols Guard interval is introduced in each OFDM...

Ngày tải lên: 19/06/2014, 19:20

... state information required at the receiver, we will introduce four types of combining schemes, including selection combining, switch combining, EGC, and MRC, in the following 2.1.1 Selection combining ... diversity (Giannakis et al., 2006) In this section, we first present various receive diversity schemes, including selection combining, switch combining, equal-gain combining (EGC), and MRC The well-known ... next-generation wireless communications In general, an MIMO system has capability to offer three types of antenna gains: diversity gains, multiplexing gains and beamforming gains A wide variety...

Ngày tải lên: 19/06/2014, 19:20

... ordering V-BLAST algorithms Beamforming Beamforming is a promising signal processing technique used to control the directions for transmitting or receiving signals in spatial-angular domain (Godara, ... Recent Advances in Wireless Communications and Networks Will-be-set-by -IN- TECH Symbol mapping Segment S/P Grouping CDD STBC GO-CDM Symbol mapping Segment S/P Grouping IFFT CP CDD Spreading IFFT CP ... be mainly determined by the groups and classes whose matrices Gg,c = Gmin g,c min Tg,c Rmin Tg,c g H (42) have the smallest common rank, denoted by min ˜ Dmin = rank(Gmin ) = rank Tg,c Rmin Tg,c...

Ngày tải lên: 19/06/2014, 19:20

... detection process taking into account the group size in the GO-CDM component while assuming that an efficient ML implementation, such as the one introduced in (Fincke & Pohst, 1985), is in use To this ... length in a lattice, including a complexity analysis, Math Comput 44: 463–471 Foschini, G (1996) Layered space-time architecture for wireless communication in a fading environment when using multi-element ... multiplexing in fading channels, IEEE Trans Commun 50: 1266–1273 116 22 Recent Advances in Wireless Communications and Networks Will-be-set-by -IN- TECH Meyer, C (2000) Matrix analysis and applied linear...

Ngày tải lên: 19/06/2014, 19:20

... time and accounting for diversity and suppressing noise in spatial 150 12 Recent Advances in Wireless Communications and Networks Will-be-set-by -IN- TECH diversity brunches Depending on amount of ... combined to for Z ( N ) In the intermediate case both components are combined according to (67) with more and more emphasis put on in- phase component X ( N ) as coherency increases with increase ... already under study in LTE under the Coordinated 166 Recent Advances in Wireless Communications and Networks Multipoint (CoMP) concept (3GPP LTE, 2007) that although not included in the current releases,...

Ngày tải lên: 19/06/2014, 19:20

... wireless/ optical architecture, In Proceeding of IEEE WCNC’10, 2010 Foschini, G J & Gans, M J (1998) On limits of wireless communications in a fading environment when using multiple antenna, Wireless Personal ... using the precoding vectors defined in (25) and considering (26), the received signal in (24) reduces to, B eq yk ,l = ∑ pb , k , l hb , k ,l sk ,l + nk , l b =1 (27) 176 Recent Advances in Wireless ... minimizing the sum of inverse of SNRs, and a closedform expression can be obtained Note that minimizing the sum of inverse of SNRs is similar to the maximization of the harmonic mean of the SINRs...

Ngày tải lên: 19/06/2014, 19:20

... deteriorate QoS in WLAN, such as increasing blocking probability in WLAN So the joint call admission control needs to be optimized to achieve the minimum blocking probability per Erlang in the integrated ... is a monotonically increasing continuous function of δ , while blocking probability and dropping probability in UMTS cell are continuous decreasing functions over δ in the interval between zero ... Handoff Issues in 4G Wireless Systems An Overview, Proceedings of International Latin American and Caribbean for 210 Recent Advances in Wireless Communications and Networks Engineering and Technology...

Ngày tải lên: 19/06/2014, 19:20

... code line 27 in Fig 2) To make it compatible with IPv6, lines indicated in Table should be replaced int main(int argc, char *argv[]) { int sockfd, newfd; socklen_t sin_size; struct sockaddr _in local; ... Advances in Wireless Communications and Networks one data stream between source and destination endpoints Multistream SCTP includes multistreaming, and finally, multihomed SCTP incorporates multihoming ... sockaddr _in6 remota6; host = gethostbyname2(argv[1], AF_INET6); local6.sin6_family = AF_INET6; local6.sin6_flowinfo = 0; local6.sin6_port = htons(MY_PORT); local6.sin6_addr = in6 addr_any; if((bind(sockfd,...

Ngày tải lên: 19/06/2014, 19:20