và tdma kiểu phân phối theo yêu cầu dama
Bài giảng môn hệ THỐNG VIỄN THÔNG
Ngày tải lên :
06/12/2015, 14:07
... trng mt in tớch im dao ng theo phng thng ng ti mt im sinh s lan truyn khụng gian di dng súng Súng ú c gi l súng in t Ngi ta núi rng in tớch dao ng ó bc x súng in t Nu xột theo mt phng truyn Ox, ... t Nu xột theo mt phng truyn Ox, súng in t l súng ngang cú thnh phn in dao ng theo phng thng ng v thnh phn t dao ng theo phng nm ngang Hỡnh 1.1 Súng in t lan truyn khụng gian Tn s súng in t bng ... o chuyn ng ca ht õy l h thc bt nh Heisenberg Trong ú x bt nh (sai s) v to theo phng x vx bt nh (sai s) v tc theo phng x Nu x cng nh thỡ vx cng ln, ngha bt nh v to cng nh thỡ bt nh v tc...
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Báo cáo hóa học: " Bounds on the Outage-Constrained Capacity Region of Space-Division Multiple-Access Radio Systems" docx
Ngày tải lên :
23/06/2014, 01:20
... 1999 [3] T M Cover and J Thomas, Elements of Information Theory, John Wiley & Sons, New York, NY, USA, 1991 [4] R Gallager, Information Theory and Reliable Communication, John Wiley & Sons, New ... Biglieri, J Proakis, and S Shamai, “Fading channels: information-theoretic and communications aspects,” IEEE Transactions on Information Theory, vol 44, no 6, pp 2619– 2692, 1998 1298 [6] D N C Tse ... Information Theory, vol 44, no 7, pp 2796–2815, 1998 [7] S V Hanly and D N C Tse, “Part II: Multiaccess fading channels II Delay-limited capacities,” IEEE Transactions on Information Theory, vol...
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Code Division Multiple Access (CDMA) phần 6 docx
Ngày tải lên :
07/08/2014, 21:20
... estimate is significantly more conservative but is still approximately five times what we predicted for TDMA/ FDMA schemes Downlink The previous discussion examined the uplink, which, as discussed, is ... the number of users approaches 35 This is referred to as pole capacity K pole and refers to the theoretical maximum number of users that can be supported This value can be obtained by solving...
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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
Ngày tải lên :
22/06/2014, 23:20
... spreading,” IEEE Transactions on Information Theory, vol 45, no 2, pp 622–640, 1999 [6] A J Viterbi, “Very low rate convolutional codes for maximum theoretical performance of spread-spectrum multiple-access ... superimposed data layers can be well approximated as a Gaussian random variable due to the central limit theorem H Schoeneich and P A Hoeher make sure that the channel is approximately invariant over ... 641–649, 1990 [7] P A Hoeher and H Schoeneich, “Interleave-division multiple access from a multiuser theory point of view,” in Proceedings of 4th International Symposium on Turbo Codes & Related Topics...
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Code Division Multiple Access CDMA pdf
Ngày tải lên :
27/06/2014, 14:20
... readers are assumed to be generally familiar with basic stochastic processes, detection theory, and communication theory The book builds on these fundamentals by explaining how spread spectrum systems ... It should be noted that frequency reuse is classically associated with FDMA Theoretically, there is no reason why pure TDMA cannot also employ reuse, although, practically speaking, synchronization ... a spread spectrum physical layer with TDMA, FDMA, or CDMA However, spread spectrum signals have a bandwidth N times larger than the data rate The use of TDMA or FDMA would require N times as...
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Code Division Multiple Access (CDMA) phần 1 doc
Ngày tải lên :
07/08/2014, 21:20
... readers are assumed to be generally familiar with basic stochastic processes, detection theory, and communication theory The book builds on these fundamentals by explaining how spread spectrum systems ... researchers in communications KEYWORDS CDMA, Multiple Access, Spread Spectrum, Multiuser Detection, TDMA, FDMA, Packet Radio Networks P1: IML/FFX MOBK023-FM P2: IML/FFX QC: IML/FFX MOBK023-Buehrer.cls ... access systems in order to demonstrate the difference between CDMA and the more widely understood TDMA, FDMA or CSMA Secondly, a review of basic spread spectrum techniques is presented which are...
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Code Division Multiple Access (CDMA) phần 2 doc
Ngày tải lên :
07/08/2014, 21:20
... It should be noted that frequency reuse is classically associated with FDMA Theoretically, there is no reason why pure TDMA cannot also employ reuse, although, practically speaking, synchronization ... a spread spectrum physical layer with TDMA, FDMA, or CDMA However, spread spectrum signals have a bandwidth N times larger than the data rate The use of TDMA or FDMA would require N times as ... demonstrate the difference between the interference statistics of FDMA and CDMA systems, consider a TDMA/ FDMA system with a reuse factor of Q = As mentioned previously, the average path loss with...
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Code Division Multiple Access (CDMA) phần 3 potx
Ngày tải lên :
07/08/2014, 21:20
... (2.18b) Walsh codes of length 2i are then formed from the rows of the Haddamard matrix H2i Note that the rows of the Haddamard matrix are orthogonal, and thus can be used to form 2i orthogonal ... can use Walsh codes for spreading waveforms and achieve orthogonality Walsh codes are based on Haddamard matrices, which P1: IML/FFX MOBK023-02 P2: IML MOBK023-Buehrer.cls September 28, 2006 15:54 ... shown in the figures, any modulation scheme (with either coherent or non-coherent demodulation) can theoretically be used As in DS/SS, the frequency hopping is ideally transparent to the data demodulator...
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Code Division Multiple Access (CDMA) phần 4 pdf
Ngày tải lên :
07/08/2014, 21:20
... 2/Tb We now require the statistics of j =1, j =k I j,k to complete the analysis The Central Limit Theorem states that a sum of n independent random variables y = j x j will have a probability distribution ... any one term in the summation That is, for 2 independent x j , σ y = j σx j The Central Limit Theorem requires independence between x j 2 and σx j σ y ∀ j Thus, if these conditions hold, we ... number of users for N = 31 from simulation and using the standard Gaussian approximation (labeled “theory”) from (2.83) We can see that the standard Gaussian approximation is very accurate (For more...
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Code Division Multiple Access (CDMA) phần 5 ppt
Ngày tải lên :
07/08/2014, 21:20
... MOBK023-Buehrer.cls September 28, 2006 15:55 CELLULAR CODE DIVISION MULTIPLE ACCESS 79 Comparing this to TDMA or FDMA, K tdma ≈ Rb B Q (3.17) and we can see that the effective reuse factor of CDMA is Q eff = SIR ... cdma = (3.26) Comparing this equation to the TDMA and FDMA analyses, we find that for a required Eb /Io > 1, the capacity of CDMA is lower than that of TDMA or FDMA because the signals are non-orthogonal ... channels available in a given area Assuming a frequency reuse factor of Q, the capacity of TDMA/ FDMA is K tdma/ fdma = BT Q Rb (3.27) Due to universal frequency reuse, the number of channels remains...
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Code Division Multiple Access (CDMA) phần 7 pps
Ngày tải lên :
07/08/2014, 21:20
... CODE DIVISION MULTIPLE ACCESS 3.4.3 107 Admission Control Unlike TDMA/ FDMA systems, CDMA systems have a soft capacity limit That is, TDMA/ FDMA systems have a specific number of channels available, ... properties greatly enhance the overall capacity of cellular systems as compared to traditional TDMA or FDMA cellular systems However, these same properties require sophisticated radio resource...
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Code Division Multiple Access (CDMA) phần 8 potx
Ngày tải lên :
07/08/2014, 21:20
... systems can be substantially lower than those for orthogonal multiple access techniques such as TDMA or FDMA In addition, if one of the received signals is significantly stronger than the others,...
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Code Division Multiple Access (CDMA) phần 9 docx
Ngày tải lên :
07/08/2014, 21:20
... with the theoretical curves in Figure 5.11 The parallel scheme uses two stages of cancellation (S = 3) and a partial cancellation factor of 0.5 in stage [112] The simulation results and the theoretical ... Rayleigh fading and timing synchronization errors 5.5.1 AWGN Channels We first present the performance (theoretical and simulation) for AWGN channels [117] The first set of results are capacity curves...
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Code Division Multiple Access (CDMA) phần 10 pot
Ngày tải lên :
07/08/2014, 21:20
... Optimization Englewood Cliffs, NJ: Prentice Hall, 2000 [4] D Gross and C Harris, Fundamentals of Queueing Theory New York: Wiley, 1985 [5] V H MacDonald, “The cellular concept,” Bell Systems Technical Journal, ... 281–285, 1970 [9] N Abrahmson, “Development of the ALOHANET,” IEEE Transactions on Information Theory, vol 31, pp 119–123, March 1985.doi:10.1109/TIT.1985.1057021 [10] P Karn, “MACA: A new channel ... Gold, “Optimum binary sequences for spread spectrum multiplexing,” IEEE Transactions on Information Theory, vol 13, pp 619–621, October 1967 doi:10.1109/TIT.1967.1054048 [25] E H Dinan and B Jabbari,...
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BÀI BÁO CÁO -Công nghệ WCDMA(wideband code division multiple access) và tình trạng triển khai
Ngày tải lên :
02/06/2015, 17:26
... lớp RLC Điều sử dụng yêu cầu mà cho phép việc vài gói, trường hợp VoIP, cho phép thay đổi độ trễ theo mức độ truyền lại RLC • Hoạt động theo chế độ báo nhận, mà việc phân phối liệu thực đảm bảo ... thực đảm bảo với việc lần truyền lại lớp RLC với đầu vào yêu cầu tất gói phân phối • Lớp điều khiển truy nhập trung bình (MAC) Re’99 tập trung vào ánh xạ kênh lôgic thực quyền ưu tiên giống lựa ... ‘Cải tiến đường lên FDD’ để nhấn mạnh cấu trúc HSUPA theo yêu cầu báo cáo nghiên cứu Nội dung TDD chưa tiến triển vào thời điểm bắt đầu thực Re’7 Vào tháng năm 2005, công việc hoàn thành cho chức...
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Tiểu luận Orthogonal Frequency Division Multiple Access in WiMAX and LTE A Comparison
Ngày tải lên :
24/07/2015, 22:27
... thông tin phản hồi không theo chu kỳ, BTS yêu cầu máy di động để báo cáo tình trạng kênh Có chế độ khác thông tin phản hồi kênh phân biệt độ phân giải tần số chúng Tùy thuộc vào chế độ thông tin ... thuộc vào Cell-ID (gọi đường xuống sở [DLPB]) quy định rõ ràng tiêu chuẩn Một nhìn tổng quát vị trí sóng mang phân phối toàn băng, hình Tất thông điệp điều khiển gửi phương pháp phân kênh dựa phân ... giúp đạt mục tiêu nguồn tài nguyên chia thành đơn vị nhỏ phân bổ cho dịch vụ khác theo yêu cầu Khả hệ thống OFDM tích hợp với nhiều đầu vào nhiều đầu ra(MIMO-OFDM) công nghệ yếu tố quan trọngtrong...
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Interleaved frequency division multiple access with multiple antennas and block spreading for mobile broadband communications
Ngày tải lên :
08/09/2015, 18:24
... System Model for coded MIMO-IFDMA 22 2.4 Theoretical Upper Bound for Exponential Decay vs Uniform Power Delay Profile for S = 32 29 2.5 Theoretical Upper Bound for Exponential ... BS-IFDMA Systems 54 ix 3.1 Theoretical BER Performance Comparison for proposed ASD and CDD 69 3.2 Theoretical BER Performance Comparison for Combined ... time division multiple access (TDMA) and code division multiple access (CDMA) also gained prominent usage in the digital 2G systems Popular 2G systems include the TDMA/ FDMA based Global System...
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Inter carrier interference suppression in orthogonal frequency division multiple access (OFDMA) systems uplink
Ngày tải lên :
14/09/2015, 14:03
... matrix H u is essentially the Hadamard product† between the channel frequency response matrix † Hadamard Product: For two matrices of the same dimensions A and B , the Hadamard product or entry-wise ... Access (OFDM -TDMA) , Code Division Multiple Access (OFDM-CDMA or MC-CDMA) and Frequency Division Multiple Access (OFDM-FDMA) These schemes are briefly introduced as below A OFDM -TDMA As illustrated ... (OFDM-FDMA) These schemes are briefly introduced as below A OFDM -TDMA As illustrated in Fig.1.4(a), OFDM -TDMA places different users into different time slots Each user occupies the whole bandwidth in...
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