time division multiple access techniques ppt
Báo cáo hóa học: " Research Article An Adaptive Time-Spread Multiple-Access Policy for Wireless Sensor Networks" pot
... [12]. Note however, that a time division sys- tem requires global synchronization which is not easily real- izable [20]. However, as in most of the cases in the area of time division MAC protocols, ... pp. 298– 306, 1998. [16] Z. Cai, M. Lu, and C. N. Georghiades, “Topology-transparent time division multiple access broadcast scheduling in multi- hop packet r adio networks,” IEEE Transactions ... is the use of time slots that are not allocated un- der the D-Policy but allow for corruption-free transmissions. Under the P-Policy, these time slots are utilized according to an access probability...
Ngày tải lên: 22/06/2014, 19:20
Báo cáo hóa học: " Iterative Pilot-Layer Aided Channel Estimation with Emphasis on Interleave-Division Multiple Access Systems Hendrik Schoeneich and Peter Adam Hoeher" docx
... INTRODUCTION Spread-spectrum multiple access is a popular technique al- lowing several users to share the same bandwidth at the same time. Spread spec trum is often equated with direct-sequence code -division multiple access ... spread-spectrum multiple- access channels,” IEEE Journal on Selected Areas in Communications, vol. 8, no. 4, pp. 641–649, 1990. [7] P. A. Hoeher and H. Schoeneich, “Interleave -division multiple access ... where he is currently work- ing as a Research Assistant. His research interests include multiple access techniques, iterative multiuser detection, turb o equalization, semiblind channel estimation,...
Ngày tải lên: 22/06/2014, 23:20
Báo cáo hóa học: " Bounds on the Outage-Constrained Capacity Region of Space-Division Multiple-Access Radio Systems" docx
... cases. 2 ant., time share 4 ant., time share 8 ant., time share 16 ant., time share 00.511.522.533.54 4.55 Rate of user 1 (nat) 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 Rate of user 2 (nat) Figure 4: Time- share ... proposed in [12] to maximize the sum capacity of a time invariant Gaussian MIMO multiple- access channel. The ergodic capacity region for MIMO multiple- access channel with covariance feedback has been ... multiple- access system with multiple antennas at the base station. Most previous studies are constrained to either fixed channel condition [11, 12] or ergodic capacity region [13]. The space-division...
Ngày tải lên: 23/06/2014, 01:20
Code Division Multiple Access CDMA pdf
... understood orthogonal access techniques such as time division multiple access and frequency division multiple access. Additionally, random access schemes such as carrier sense multiple access are examined. In ... contention-free multiple access is in how the channels are defined. In time division multiple access (TDMA), channels are defined according to time slots. In frequency division multiple access (FDMA), ... 64 2.8 Multiple Access Performance of Frequency-Hopped Code Division Multiple Access 67 2.9 Summary 71 3. Cellular Code Division Multiple Access 73 3.1 Principles of Cellular Code Division Multiple...
Ngày tải lên: 27/06/2014, 14:20
Multiple Access Techniques for Wireless Communications ppsx
... structures. Time Division Multiple Access (TDMA) (6) Wireless Access Tech. Lab. CCU Wireless Access Tech. Lab. TDMA Frame Structure Time Division Multiple Access (TDMA) (5) Wireless Access ... Frequency Division Multiple Access (FDMA) (3) Wireless Access Tech. Lab. CCU Wireless Access Tech. Lab. Spread Spectrum Multiple Access (8) Wireless Access Tech. Lab. CCU Wireless Access ... transmit simultaneously. Frequency Division Multiple Access (FDMA) (1) Wireless Access Tech. Lab. CCU Wireless Access Tech. Lab. Time Division Multiple Access (TDMA) (4) Features of TDMA...
Ngày tải lên: 11/07/2014, 21:20
Luận văn kỹ thuật cdma (code division multiple access) luận văn, đồ án, đề tài tốt nghiệp
Ngày tải lên: 25/07/2014, 09:39
Báo cáo hóa học: " Research Article Capacity of Time-Hopping PPM and PAM UWB Multiple Access Communications over Indoor Fading Channels" ppt
... receive diversity. 4. CAPACITY ANALYSIS OF A TIME- HOPPING MULTIPLE ACCESS PPM OR PAM UWB SYSTEM With more than one user active in the system, multiaccess interference (MAI) is a major factor limiting ... the capacity analysis given in Section 3 for a single user to be extended to a multiple- access system. 4.1. Multiple- access interference model Asgivenin(4), the received signal is modeled as r(t) = K k=1 L l=1 a lk (t)X (k) l t ... active in the multiple- access system, the optimal PPM receiver has a complex structure that takes advantage of all receiver knowledge regarding the characteristics of the multiple- access interference...
Ngày tải lên: 21/06/2014, 22:20
báo cáo hóa học:" Decentralized estimation over orthogonal multiple- access fading channels in wireless sensor networks-- optimal and suboptimal estimators" ppt
... log-likelihood function. However, because the log-likelihood function shown in (11) is non-concave and has multiple extrema, we need to find all its local maxima to get the global maximum. Exhaustive searching ... be less than ∆/N; thus, we need to compute t h e value of the likelihood function at least M × N times to obtain the MLE. The FC applies (11), (12) and (13) to compute the values of the likelihood ... therein). They reduce the observation noise by exploiting the redundant observations provided by multiple sensor s . However, their performance degrades dramatically when communication errors cannot...
Ngày tải lên: 20/06/2014, 04:20
Báo cáo hóa học: " Multihop relaying and multiple antenna techniques: performance trade-offs in cellular systems" ppt
... Interface for Broadband Wireless Access Systems (May 2009). IEEE Std. 802.16-2009 22. Universal mobile telecommunications system (UMTS); spatial channel model for multiple input multiple output (MIMO) ... the SINR pro- vides higher spatial multiplexing gain, but reducing scat- tering reduces spatial multiplexing gain. To put this ano the r way, MIMO ’s spatial multiplexing and diversity gains are ... with multiple antenna techniques with the goal of achieving higher data carry- ing capacity simultaneously with good system coverage. Much research has emerged recently on MH relaying and multiple...
Ngày tải lên: 21/06/2014, 01:20
Báo cáo hóa học: " Research Article Analysis of Coded FHSS Systems with Multiple Access Interference over Generalized Fading Channels" ppt
... spread-spectrum multiple- access communications over fading channels,” IEEE Transactions on Communications, vol. 30, no. 5, part 2, pp. 996–1009, 1982. [3] G. Einarsson, “Coding for a multiple- access frequency- hopping ... starts transmitting his data over a narrow band during a time slot (called dwell time) , and then hops to other bands in the subsequent time slots according to a pseudorandom (PN) code (sequence) ... the frame size. In cellular networks, multiple access interference (MAI) may arise when more than one user transmit over the same frequency band at the same time in the uplink. This happens when...
Ngày tải lên: 21/06/2014, 23:20