time coding on frequency selective fading channels

... Channel Estimation on Code Performance Design of Space -Time Trellis Codes on Fast Fading Channels Performance Evaluation on Fast Fading Channels Space -Time Turbo Trellis ... Space -Time Coding for Wideband Systems 8.1 Introduction 8.2 Performance of Space -Time Coding on Frequency- Selective Fading Channels 8.2.1 Frequency- Selective ... criteria on slow fading channels with two transmit and one receive antennas Performance comparison of the QPSK codes based on the trace criterion on slow fading channels...

Ngày tải lên: 26/10/2014, 14:30

... In addition to the flat fading, other fading situations, such as time- selective and frequency- selective fading, were also discussed in some researches to address communications with the wide band ... in space Sometimes the quasi-static fading or rapid fading is hardly the accurate description of the fading environment The block fading, such 12 1.3 Literature Review as the one considered in ... rapid fading This motivates us to study the code design in composite fading channels, in which some users have quasi-static fading channels and the others have rapid fading channels Our discussion...

Ngày tải lên: 14/09/2015, 12:11

... environments such as mobile handset to achieve excellent performance More details on AES can be found in [7] As mentioned before, we will focus our discussion on IS-95 system as it has a stronger ... follows (1) The base station and the mobile station share a common initial state for the LFSR and an L-bit (L = 128, 192 or 256) common secret encryption key K (2) The long scrambling sequence ... between the mobile station and base station can be updated from time to time To prevent malicious key reload, the key update request can only be initiated from the base station SECURITY OF THE PROPOSED...

Ngày tải lên: 22/06/2014, 19:20

... optimization of the local decision/censoring threshold is provided in Section Simulation and numerical results are given in Section 5, while some conclusions are drawn in Section Notation In this ... symbol duration This is usually a reasonable assumption for low-rate WSN applications We refer the interested reader to [18] for a more detailed discussion on time synchronism in the context of ... decision) Therefore, only noncoherent decision rules will be considered in the next section The received vector can be expressed as FC DECISION RULES AND PERFORMANCE ANALYSIS In this section, we...

Ngày tải lên: 22/06/2014, 19:20

... transmission over frequency- selective MISO channels has been investigated in a number of recent contributions [8, 9, 10, 11] Maximum-likelihood (ML) decoding in MISO frequency- selective channels ... detection based on joint MMSE decision-feedback equalization (DFE) and decoding (notice that sequence detection for TR-STBC without outer coding has been considered in [16, 17]) The decisions for ... nonoptimality of GODs for M > [6] A Low-Complexity STC for Multipath Fading Channels CONCLUSION We proposed a concatenated TCM-TR-STBC scheme for single-carrier transmission over frequency- selective...

Ngày tải lên: 23/06/2014, 00:20

... results within a given time constraint Timing constraints include finish time, or both start time and finish time A good way to understand the relationship between real -time systems and embedded ... real -time systems Similar to embedded systems, real -time systems also have substantial knowledge of the environment of the controlled system and the applications running on it This reason is one ... sections Each section has a type Content is placed into a section if the section type matches the type of the content being stored A section also contains important information such as the load...

Ngày tải lên: 08/03/2016, 11:37

... user k from antenna i at time n 3) Time- Frequency mapping : The output of the space -time spreading is then mapped in time and frequency before IFFT Fig describes the Time- Frequency mapping method ... a slow fading frequency- selective environment Fig BER comparison for OFDM-CDMA system with 4Tx, 2Rx of the proposed scheme (solid) and 2D OFDM-CDMA (dotted) in a slow fading frequency- selective ... (CDMA); diversity; space time frequency spreading; multipleinput multiple-output (MIMO) systems; orthogonal frequency- division multiplexing (OFDM); 4th generation (4G) Introduction Modern broadband...

Ngày tải lên: 18/06/2014, 22:20

... slow fading frequency- selective environment Conclusion In this paper, we have proposed an open-loop MIMO OFDM-CDMA scheme using space -time- frequency spreading (STFS), in the presence of frequency- selective ... user k from antenna i at time n 3) Time- Frequency mapping The output of the space -time spreading is then mapped in time and frequency before IFFT Figure describes the Time- Frequency mapping method ... bit on space, time and frequency in a parallel manner was considered to be a complicated issue [20] However, the proposed OFDMCDMA has efficient mapping in bit allocation in space, time and frequency...

Ngày tải lên: 20/06/2014, 21:20

... to only one user Therefore, assuming a base station has only a single transmit and single receive frequency, it can only accommodate a single user In addition, due to the limitations of the frequency ... information User information in this case is usually split into two information streams, one corresponding to an "in-phase'' or "I" component and one corresponding to a "quadrature" or "Q" component ... acceptable emissions limits are exceeded, the system may be in violation of national or international regulations For instance, the International Telecommunications Union (ITU) has emissions limits...

Ngày tải lên: 18/04/2014, 12:26

... the flexible dynamic frequency allocation specific to OFDMA In its frequency domain implementation [8], SC-FDMA is a precoded OFDMA transmission scheme, where precoding is done by means of a DFT ... structure does not correspond to a double SC-SFBC construction and the conventional MMSE simplified detector cannot be employed anymore A joint MMSE detection over all the bandwidth containing cross-codes ... allocations After the introduction in Section 1, we will briefly review the principles of SC-SFBC in Section Section states the problems raised by employing SC-SFBC in an MUMIMO transmission and...

Ngày tải lên: 21/06/2014, 00:20

... account our focus on the correlation properties of the sequences, we introduce in the generation process a constraint related to cross-correlation: when two generation paths share a common pattern of ... cross-correlation performance The bound is a lower one, as a consequence, by evaluating such bound over different code sets we can draw conclusions about the one providing the worst performance, i.e., the one ... chosen, by excluding the corresponding complementary ones, so that they may result orthogonal with respect to the corresponding cross-correlation At the same time, 32 OVSF sequences are generated,...

Ngày tải lên: 21/06/2014, 03:20

... the addition operations is O(N M) The proposed approach consists of the synchronization phase and the tracking phase The multiplication and addition operations in the synchronization phase of ... transition time K in (11) and (13) is obtained from the estimation of K If K = K, then one of the two subblocks contains both / frequencies ω1 and ω2 and the other subblock contains only one frequency ... time rather than exponential time An algorithm with a complexity of O(MN) can be treated as feasible for real -time application Simulations Results In this section, numerous simulations are conducted...

Ngày tải lên: 21/06/2014, 08:20

... based on the different ranges of Doppler frequencies (or mobile velocities), is constructed to treat the time- varying fading channel [17] In addition, a decisiondirected channel estimation in the frequency ... decision-directed channelestimation algorithm in the time domain is developed The conventional channel-estimation methods for multicarrier transmission systems are equipped with pilots in the frequency ... duration The conventional decision-directed methods will fail in this situation because all of them feed the previous estimates to the MMSE detector for current detection Based on the decision-directed...

Ngày tải lên: 21/06/2014, 08:20

... BER The one-dimensional (1D) optimization performed in Step for finding λ p speeds up the convergence considerably in comparison to the use of a constant value for λ p The 1D search is done by ... certain channel condition Eb / N0 , these values can be used as initial values for other channel conditions which are close to the one already optimized As a termination criterion for the steepest ... vectors that generate the cone compared to the original receiver outside the cone Since 12 EURASIP Journal on Wireless Communications and Networking the Q-function is monotonic decreasing, it is...

Ngày tải lên: 21/06/2014, 22:20

... joint DS-CDMA space -time MUD system with error control coding over a multipath fading channel The authors of [20] use convolutional coding for error control coding and a space -time MMSE detector ... detector at reception propagating through a Rayleigh fading channel We use an MMSE/PIC MUD coupled with STBC to achieve space -time multiuser detection Depending on the concatenation scheme used, ... section, we consider the simulated performance of a synchronous turbo coded DS-CDMA system that employs an MMSE front-end turbo space -time multiuser detector at reception The communication model...

Ngày tải lên: 21/06/2014, 23:20

... if it converges and the condition of convergence is < μ < This will be validated in the simulation section SIMULATION RESULTS To show the important reduction in computational complexity one can ... if the condition KL ≤ 3N is satisfied Moreover, all the aforementioned convergence analysis and conditions of convergence are valid for this case as well, that is, the proposed structure converges ... relaxation (acceleration) since the interval ]0, 1[ corresponds to under relaxation (deceleration) and it is basically used to ensure convergence of the block Gauss-Seidel iteration if it is not convergent...

Ngày tải lên: 22/06/2014, 00:20

... if it converges and the condition of convergence is < μ < This will be validated in the simulation section SIMULATION RESULTS To show the important reduction in computational complexity one can ... if the condition KL ≤ 3N is satisfied Moreover, all the aforementioned convergence analysis and conditions of convergence are valid for this case as well, that is, the proposed structure converges ... relaxation (acceleration) since the interval ]0, 1[ corresponds to under relaxation (deceleration) and it is basically used to ensure convergence of the block Gauss-Seidel iteration if it is not convergent...

Ngày tải lên: 22/06/2014, 06:20

... control for discrete -time nonlinear nonnegative uncertain systems In this section, we consider the problem of characterizing neuroadaptive feedback control laws for discrete -time nonlinear nonnegative ... nonnegative integers The following definition introduces the notion of a nonnegative resp., positive function Definition 2.1 A real function u : Z → Rm is a nonnegative resp., positive function ... of Section to the case where control inputs are constrained to be nonnegative Finally, in Section we draw some conclusions Mathematical preliminaries In this section we introduce notation, several...

Ngày tải lên: 22/06/2014, 11:20

... positions j −1 Position 2( j − 1) + t=1 Lt + contains a j −1 Position 2( j − 1) + t=1 Lt + contains a j −1 Position 2( j − 1) + t=1 Lt + i + contains a −1 j −1 Position 2( j − 1) + t=1 Lt + contains ... formulation in which the decision epoch is chosen as the arrival and departure of each transmission round Based on these decision epoches, the time duration until the next state remains exponentially ... Position 2( j − 1) + t=1 Lt + i + contains a −1 j −1 and position 2( j − 1) + t=1 Lt + i + contains a j −1 Position 2( j − 1) + t=1 Lt + contains a −1 j −1 Position 2( j − 1) + t=1 Lt + L j + contains...

Ngày tải lên: 22/06/2014, 19:20