... (nat) Rate of user (nat) 50%, upper 10%, upper 1%, upper 50%, upper 10%, upper 1%, upper (a) (b) Figure 3: Outer bound on outage capacity regions for (a) and (b) 16 antenna elements at the base ... invariant Gaussian MIMO multiple- access channel The ergodic capacity region for MIMO multiple- access channel with covariance feedback has been studied in [13] In this paper, we consider the outage ... 0 0.5 ant., lower ant., upper ant., lower ant., upper (a) 1.5 2.5 3.5 Rate of user (nat) Rate of user (nat) ant., lower ant., upper ant., lower ant., upper (b) Figure 6: Both outer and inner bounds...
... of the low-complexity suboptimal sliding-window channel estimator from Section 4.2.4 6. 1 Perfect channel knowledge Let us first consider perfect channel knowledge The following results lead us ... Information Theory, vol 45, no 2, pp 62 2 64 0, 1999 [6] A J Viterbi, “Very low rate convolutional codes for maximum theoretical performance of spread-spectrum multiple- access channels,” IEEE Journal on ... received data based on channel estimates Joint channel estimation is used to estimate multiple channels (in our case U channels) jointly For JLSCE, the channels have to be assumed invariant over...
... transmitters blindly transmit without attempting to determine if the channel is in use Carrier sense multiple access (CSMA) and carrier sense multiple access/collision avoidance (CSMA/CA) are both contention-based ... that persistent-1 CSMA can provide better throughput than ALOHA and non-persistent CSMA at low loading levels However, at high system loading factors, non-persistent CSMA provides far superior performance ... in Section 2.4 The link performance and multiple access capabilities of DS-CDMA will be discussed in Sections 2.5 and 2 .6, respectively, and the link performance and multiple access capabilities...
... 28, 20 06 15:54 CODE DIVISION MULTIPLE ACCESS (CDMA) 10 K=1 K = 10 K = 20 K = 30 K = 40 -1 10 -2 10 Probability of bit error 62 -3 10 -4 10 -5 10 -6 10 10 Eb/No (dB) 12 14 16 18 20 FIGURE 2 .27: Probability ... symbols increases However, the performance improvement decreases rapidly with increasing M P2: IML MOBK023-Buehrer.cls 66 September 28, 20 06 15:54 CODE DIVISION MULTIPLE ACCESS (CDMA) 100 AWGN, ... paths 6, 9, and 12dB below the main path for the four-path case) 100 L=1 Equal strength -3 dB -6 dB -12 dB -18 dB AWGN -1 10 Probability of bit error 10-2 10-3 10-4 10-5 10 -6 10 15 SNR per bit...
... a single channel by multiple information streams For example, ten 3-kbps information streams can be time-multiplexed onto a single 30-kbps channel In time-multiplexing, the overall channel capacity ... FDMA, each channel will see one to seven interfering signals In CDMA, each channel will see P1: IML/FFX MOBK023-03 P2: IML MOBK023-Buehrer.cls 74 September 28, 20 06 15:55 CODE DIVISION MULTIPLE ... the SIR is −110dBm + 130dBm = 20dB and the standard deviation √ is + 36 = 6. 08dB Converting to base e , 20 ln (10) 10 = 4 .61 6. 08 ln (10) σ = 10 = 1.40 μ= (3.2) (3.3) Now we wish to find X such...
... Specifically, lim ηUL = (3 .66 a) ηUL = (3 .66 b) Itotal →∞ lim (Iic +Io c )→0 P2: IML MOBK023-Buehrer.cls 108 September 28, 20 06 15:55 CODE DIVISION MULTIPLE ACCESS (CDMA) Now, rearranging (3 .64 ), we can write ... spectrum brings with it the possibility of multiple channels since multiple spreading codes are possible With multiple channels, we now must determine which channels (i.e., codes) the receiver should ... coding Frequency hopper Frequency dehopper Demodulation decoding Frequency dehopper Demodulation decoding Channel Rx Rx N frequency slots Source K Modulation and coding Frequency hopper FIGURE 4.5:...
... frequency selective Rician fading channels [64 , 65 ] as well as flat and frequency selective Rayleigh fading channels (both coherent and differentially coherent) [66 –71] The most notable difference ... MOBK023-Buehrer.cls 130 September 28, 20 06 15: 56 CODE DIVISION MULTIPLE ACCESS (CDMA) addressed by Schneider [ 56] for both the synchronous and asynchronous AWGN channels Verd´ expanded this work by ... MOBK023-05 P2: IML MOBK023-Buehrer.cls 1 36 September 28, 20 06 15: 56 CODE DIVISION MULTIPLE ACCESS (CDMA) The decorrelator can also be extended to non-AWGN channels For example, the receiver can...
... data bit and channel gain: ˆ b k = sgn Tb Tb r (t) − 2yi a i (t) cos(ωc t) a k (t) cos(ωc t)d t (5 .66 ) i=K The analytical performance of this parallel cancellation approach in an AWGN channel can ... 5.13: Performance degradation in near-far channels (AWGN, Eb /No = 5dB for desired user and spreading gain = 31) P1: IML/FFX MOBK023-05 P2: IML MOBK023-Buehrer.cls 160 September 28, 20 06 15: 56 CODE ... (−1)s Ps s =0 n (5.88) P1: IML/FFX MOBK023-05 P2: IML MOBK023-Buehrer.cls 1 56 September 28, 20 06 15: 56 CODE DIVISION MULTIPLE ACCESS (CDMA) If we let M → ∞, M (−1)s Ps lim M→∞ = R−1 (5.89) s =0...
... 28, 20 06 15: 56 MULTIUSER DETECTION 165 (1.25ms) This corresponds to Walsh symbols in IS-95, allowing multiplechannel observations per estimate and a corresponding 7dB improvement in channel ... September 28, 20 06 15: 56 MULTIUSER DETECTION 5 .6. 2 167 Performance in an Additive White Gaussian Noise Channel Our initial investigation of PIC for IS-95 focuses on the simplest case: an AWGN channel ... 36, pp 48–54, September 1998.doi:10.1109/35.71 461 6 [ 26] T Kasami, “Weight distribution formula for some class of cyclic codes,” University of Illinois – Urbana, Tech Rep R-285, April 1 966 [27] ...
... liệu Nghiệp đoàn di động toàn cầu (GSA) công nghệ 3,5G (HSDPA) chiếm đến 69 % tổng số mạng di động toàn cầu Nếu 20 06, có 166 mạng di động hỗ trợ HSDPA 75 nước, kết thúc năm 2007, số nhà mạng sử ... triển, gồm có HS-SCCH (High Speed Shared Control Channel – kênh điều khiển dùng chung tốc độ cao), HS-DPCCH (High Speed Dedicated Physical Control Channel – kênh điều khiển vật lý dành riêng tốc ... bị công nghệ phân bố nhiều vùng khác giới, Tây Âu (61 mạng), tiếp Nam Á (35), Đông Âu (34), Trung Đông châu Phi (20), châu Mỹ vùng Caribbe ( 16) .HSDPA nhiều vùng có tốc độ download lên tới 7,2...
... - In LTE, BTS uses the channel feedback from the mobile to schedule an RB for the user in a frame - The feedback can be periodic - Different modes of channel feedback - Channel feedback can be ... DIVERSITY - The subcarriers used in a reference subchannel in a reference cell are - In LTE, there can be a clash in the positions of the data subcarriers that distributed in different subchannels in ... LTE, 12 adjacent subcarriers are grouped as a unit in the subcarriers in an OFDM symbol frequency axis, and OFDM symbols (or OFDM symbols in A slot is formed by combining a subchannel with different...
... triển WiMax WiMAXv2 dựa tiêu chuẩn IEEE 802.16m, có khả tương thích ngược với hệ thống WiMAX 802.16e tiêu chí quan trọng Với đặc điểm OFDMA, 802.16m không sử dụng ký hiệu kênh khái niệm PUSC ... gian cố định mức 10 ms,không phân biệt băng thông hoạt động, trình tự gửi trung tâm có 64 sóng mang chiếm 0. 96 MHz băng thông.Do đó,không giống phần đầu WiMAX,số lượng sóng mang sử dụng PSS cố định ... 1024 sóng mang 1/3 ( bảo vệ sóng mang con) sử dụng cho truyền dẫn preamble Performance Bounds For Syschronization and Channel Estimation Thông thường, ước lượng kênh WiMax sử dụng preamble Tuy...
... 47 2 .6. 3 Effects of Varying Number of Paths to Keep in Each Stage 48 2 .6. 4 Varying Number of Channel Paths 48 2 .6. 5 Multiple Receive Antennas System 50 2 .6. 6 Spatial Multiplexing ... 99 4.5 Theoretical Performance Analysis 101 4 .6 Simulation Results 108 4 .6. 1 4 .6. 2 Channel Dependent Code Assignment 109 4 .6. 3 System BER with ... MMSE QRD 46 2.9 BER Performance Comparison for Varying M 47 2.10 BER Performance for P = 49 2.11 BER Performance for P = 16 49 2.12 BER Performance...
... Fig.4 .6: Samples selection for channel estimation from FFT-demodulated OFDMA block 62 Fig.4.7: MSE performance of LS-T and LMMSE 68 Fig.4.8: Comparison between LS-T and LS-F 69 ... Algorithms 56 4.3.3 Frequency-domain Estimation 58 4.4 CRLB Analysis for LS Estimators 63 4.5 Numerical Results and Discussion 66 4.5.1 Performance of Estimation ... BER performance comparison of the MMSE and PIC detectors with and without power control 96 Fig.5.8: BER performance for different number of users under perfect power control 96 Fig.5.9:...