random access channel rach
Radio network planning and optimisation for umts 2nd edition phần 2 pptx
... Transport Channels Physical Channels DCH Dedicated Physical Data Channel (DPDCH) Dedicated Physical Control Channel (DPCCH) RACH Physical Random Access Channel (PRACH) CPCH Physical Common Packet Channel ... transmission, showing N parallel physical channels Access Slot #0 Random Access Transmission Access Slot #1 Access Slot #7 Access Slot #8 5120 chips #0 Access slot #14 #1 #2 #3 #4 #5 #6 #7 #8 #9 ... control commands [11] Physical Random Access Channel (PRACH) Random access transmission is based on a slotted ALOHA approach with fast acquisition indication There are 15 access slots per two frames...
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Báo cáo hóa học: " Research Article Joint Sensing Period and Transmission Time Optimization for Energy-Constrained Cognitive Radios" doc
... efficiently access the channel, and meanwhile consumes less energy and time to sense the channel s state than the reference policies, namely, probabilistic access policy and no sensing access policy ... illustrates the maximal channel utilization under three different access policies From this figure, we can obtain that when P is small, the channel utilization under three access policies are the ... ) We assume the channel state information μ and λ are known to SU 2.3 SU’s Access Policies The SU’s access policy, that is, the allocation of transmission time, will affect the channel utilization...
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finitte difference time domain studies on optical transmission through planar
... excited propagation mode inside the channel In this case, a TE20 mode [Fig 2(l)] is also excited and propagating along the channel Further, the field emerging from the channel is no longer concentrated ... observed in the aperture channel [Figs 2(b) and 2(f)] This TE10 mode is completely concentrated in the gap region between the ridges as shown in Fig 2(j) and propagates through the channel without losing ... cutoff wavelength c , it can propagate through the aperture channel, as the phase constant is positive The group wavelength inside the channel is related to the phase constant by g ¼ 2= The...
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finitte difference time domain studies on optical transmission through planar
... excited propagation mode inside the channel In this case, a TE20 mode [Fig 2(l)] is also excited and propagating along the channel Further, the field emerging from the channel is no longer concentrated ... observed in the aperture channel [Figs 2(b) and 2(f)] This TE10 mode is completely concentrated in the gap region between the ridges as shown in Fig 2(j) and propagates through the channel without losing ... cutoff wavelength c , it can propagate through the aperture channel, as the phase constant is positive The group wavelength inside the channel is related to the phase constant by g ¼ 2= The...
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Báo cáo hóa học: " Frequency domain equalization space-time block-coded CDMA transmission system" pdf
... This channel is 3, and σ0 named as Exponential in the figures Finally, the third channel results from the multiplication of a matrix K by ˜ the channel vector generated as in the Exponential channel ... two channel estimates were used The first one is an ideally estimated channel, denoted as Proposed in the figures, while the second one, denoted ‘Proposed w/ Error’ in the figures, is a noisy channel ... with different channel covariance matrix In the third experiment we compare the performance of the systems for three different transmission channels, all with L = paths but different channel covariance...
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Báo cáo hóa học: " Research Article Spatial Capacity of UWB Networks with Space-Time Focusing Transmission" pot
... vanishes with n, when the channel is shared by n identical randomly located nodes with random access scheme Some results of user capacity for direct sequence code-division multi -access (DS-CDMA) and ... desired tolerance The random propagation delay of the low duty-cycle signal leads to a random accessing time, and the random multipath response of the communication link induces a random “spreading ... 24] Essentially, spacetime focusing transmission in IR-UWB systems accesses the channel with a combined random time-division and random code-division scheme On one hand, IR-UWB signals are low duty-cycle...
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Báo cáo hóa học: "Performance evaluation of time-multiplexed and data-dependent superimposed training based transmission with practical power amplifier model" doc
... present the channel between transmitter and receiver as an r times oversampled discrete-time equivalent channel, heq (n) = |hRRC (t) ◦ hchannel (t) ◦ hRRC (t)|t=nT /r = |hRRC ◦ hchannel+RRC |t=nT ... apriori information of the channel tap values The ˆ apriori information of the channel taps is obtained through a least squares (LS) channel estimator From (12), the LS channel estimator can be ... the channel estimator to take into account only the most significant channel taps Both methods gain in noise power reduction in the channel estimation but lose in the asymptotic accuracy In the channel...
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Báo cáo hóa học: " Research Article Stable Transmission in the Time-Varying MIMO Broadcast Channel" pptx
... only accessing the channel a fraction of the time, the mutual information for user j will simply be 20 Expected throughput (bits /channel use) it can provide stable throughput in a time-varying channel ... antennas and P = 10 in Rayleigh, flat-fading channel model All nodes have perfect channel knowledge for all realizations of the channel over an infinite set of channel realizations, which is not possible ... existence of slowly varying subspaces in the time-varying multiuser MIMO channel SYSTEM AND CHANNEL MODELS The MIMO broadcast channel communication scenario of interest consists of a single transmitting...
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Báo cáo hóa học: " Research Article Real-Time Transmission and Storage of Video, Audio, and Health Data in Emergency and Home Care Situations" pdf
... spirometry, is provided by interfacing the medical terminal equipment data channel to the real- time data transmission channel From the physical connection point of view, medical devices are interfaced ... wirelessapplication-protocol-(WAP-) based telemedicine system for patient monitoring WAP technology devices such as mobile access terminals for general inquiry and patient-monitoring services are used Authorized users can ... the data from the portable unit are routed to a virtual private network (VPN) using a dedicated access point (APN) The portable unit system (see in Figure 4) is divided into modules which are...
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Báo cáo hóa học: " Research Article Distributed Space-Time Block Coded Transmission with Imperfect Channel Estimation: Achievable Rate and Power Allocation" pot
... channel with two receive antennas, versus the channel estimation error variance of the first subchannel, that is, σ1 , at SNR = 20 dB The channel estimation error 2 variance of the second subchannel ... distributed MIMO channels We also observe that the gap for D-STBCs changes slowly as the subchannel estimation error variances change, while Δ in SIMO subchannels increases significantly when the channel ... multiple access channel with imperfect channel estimation,” to appear in IEEE Transactions on Wireless Communications L Musavian and S A¨ssa ı [20] E Biglieri, J Proakis, and S Shamai, “Fading channels:...
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Báo cáo hóa học: " RD Optimized, Adaptive, Error-Resilient Transmission of MJPEG2000-Coded Video over Multiple Time-Varying Channels" potx
... 10 Coding unit Channel Channel 12 14 16 Channel (a) 10 Coding unit Channel Channel 12 14 16 Channel (b) Figure 16: An example of time adaptivity of packets over three time-varying channels using ... time-varying channel 0.2 0.1 2 10 Coding unit Channel Channel 12 14 16 10 Coding unit 12 Channel Channel (a) (b) Figure 15: An example of time adaptivity of packets over two time-varying channels ... Signal Processing Channel 1(n) Raw input data Source coder Channel coder Channel 2(n) Channel decoder Source decoder Output data Channel L(n) ··· Rate-distortion optimizer Figure 3: System...
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Báo cáo hóa học: " Optimizing Transmission and Shutdown for Energy-Efficient Real-time Packet Scheduling in Clustered Ad Hoc Networks" potx
... generalized version of their algorithm (rightflow) for a broadcast channel and to the multiaccess channel assuming a centralized medium access control protocol [19] In [20], a practical multiuser lazy ... taking assumptions on the channel We assume a narrowband flat fading channel is encountered Also, considering a slowly varying network topology, we can assume that the channel attenuation (due ... wireless access to vehicles (high bandwidth & driving speed), protocol boosting on wireless links, design of fixed access/ metro part, traffic engineering and QoS support in the wireless access network...
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Báo cáo hóa học: " Maximum Likelihood Turbo Iterative Channel Estimation for Space-Time Coded Systems and Its Application to Radio Transmission in Subway Tunnels" potx
... the channel is known because there is no ISI and, therefore, no “inner coding” for the Turbo processing Nevertheless, this is not true when the ML-EM channel estimator is used because the channel ... again very close to the known channel case pacity of Rayleigh fading channels, this difference being more remarkable in the case of a × system The ability of our channel estimation technique to ... the measured channel is less than the ca- CONCLUSIONS In this paper, we propose a novel ML-based time-dispersive MIMO channel estimator for STC systems that employ ML Turbo Iterative Channel Estimation...
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Báo cáo khoa học: " A morphological and molecular study of Anaplasma phagocytophilum transmission events at the time of Ixodes ricinus tick bite" pps
... distribution, and reproduction in any medium, provided the original work is properly cited This is an Open Access from: http://www.actavetscand.com/content/52/1/43 Acta article is available licensee BioMed...
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The UNIX Time Sharing System
... below 5120 can be read with a single disk access; bytes in the range 5120 to 70,656 require two accesses; bytes in the range 70,656 to 8,459,264 require three accesses; bytes from there to the largest ... designed to eliminate the differences between the various devices and styles of access There is no distinction between ‘ random ’ and ‘‘sequential’’ I/O, nor is any logical record size imposed by ... If the last byte lies beyond the end of the file, the file is made to grow as needed To random (direct -access) I/O it is only necessary to move the read or write pointer to the appropriate location...
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Real-time Software Design
... garbage collection; Not possible to discover queue sizes for shared resources; Not possible to access system hardware; Not possible to space or timing analysis ©Ian Sommerville 2004 Software ... buffer and make elements available Producer and consumer processes must be mutually excluded from accessing the same element The buffer must stop producer processes adding information to a full...
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