time codes over ofdm systems

... Space -Time Codes Over OFDM Systems 8.7.1 Concatenated RS-STC over OFDM Systems 8.7.2 Concatenated CONV-STC over OFDM Systems 8.7.3 ST Turbo TC over OFDM Systems ... Performance of concatenated RS-STC over OFDM systems Performance of concatenated CONV-STC over OFDM systems Performance of ST turbo TC over OFDM systems An open-loop ... 8.3 STC in Wideband OFDM Systems 8.3.1 OFDM Technique 8.3.2 STC -OFDM Systems 8.4 Capacity of STC -OFDM Systems 8.5...

Ngày tải lên: 26/10/2014, 14:30

... chapters 2.2 Space -time Codes In this section, we will give an overview of STCs and briefly explain its principle 2.2 Space -time Codes 25 st1 Spacetime Encoder yt1 stnT ytnR Spacetime Decoder noitamrofnI ... Motivation the space -time code (STC) [3–5] and the Bell Laboratories space -time (BLAST) architecture [6–8] STC, including the space -time trellis code (STTC) and the space -time block code (STBC), ... multiuser systems has received less attention Based on existing single-user STTCs, Ng et al proposed an interference-resistant modulation, by rotating the space -time codes for single user systems...

Ngày tải lên: 14/09/2015, 12:11

... readily be applied to 3G systems and beyond Since the channelization codes are chosen to be Walsh codes, which are easy to generate, the physical layer built-in security of CDMA systems mainly relies ... Therefore, as long as C(t) for a time instance t is known, then the entire sequence can be recovered In other words, as long as an eavesdropper can intercept/recover up to 42 continuous long-code ... system and the results can be directly applied to 3GPP systems Once the long-code sequence is recovered, the desired user’s signal can be recovered through signal separation and extraction techniques...

Ngày tải lên: 22/06/2014, 19:20

... WSNs with a large number of sensors To overcome the bandwidth limitations of orthogonal transmission in WSNs, the application of coherent distributed space -time coding was proposed in [11] In particular, ... is randomly assigned a column of Alamouti’s space -time block code (STBC) [12] and it is assumed that only two sensors are active randomly at any time The quantized observations are encoded by the ... of the coherent scheme in [11] (ii) Moreover, it is shown that censoring of local decisions is essential for the efficient application of distributed space -time coding in WSNs (iii) We derive the...

Ngày tải lên: 22/06/2014, 19:20

... recently extended to the frequency-selective case in [7] The design of space -time codes (STCs) for singlecarrier transmission over frequency-selective MISO channels has been investigated in a number ... coded modulation (BICM) with turbo equalization have been proposed in [9, 13] Time- reversal orthogonal space -time block codes (TR-STBC) [8] (see also [9]) converts the MISO channel into a standard ... [0], , gi [Ng − 1], 0, ,  (2) Ns (N −n−1) nNs 2.2 Time- reversal STBC TR-STBC [8] is a clever extension of orthogonal spacetime block codes based on generalized orthogonal designs (GODs) [19,...

Ngày tải lên: 23/06/2014, 00:20

... differentiates hard real -time systems from soft real -time systems • Real -time systems have a significant amount of application awareness similar to embedded systems • Real -time embedded systems are those ... other words, real -time systems have timing constraints and are deadline-driven Real -time systems can be classified, therefore, as either hard real -time systems or soft real -time systems What differentiates ... systems exhibit real -time behaviors nor are all real -time systems embedded However, the two systems are not mutually exclusive, and the area in which they overlap creates the combination of systems...

Ngày tải lên: 08/03/2016, 11:37

... other systems that use space -time- frequency (STF) coding as in [16], has more complexity than our proposed system Their spreading technique uses space -time block codes or space -time trellis codes ... and time spreading Different codes are assigned to different users The OFDM super-frame contains 16 OFDM symbols, which 16 is equal to the length of the time spreading code Nc = 16, where each OFDM ... 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...

Ngày tải lên: 18/06/2014, 22:20

... 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 ... other systems that use space -time- frequency (STF) coding as in [16], has more complexity than our proposed system Their spreading technique uses space -time block 20 Proposed OFDM CDMA (sim.) 2D OFDM ... both space and time spreading Different codes are 100 Proposed OFDM CDMA STF Block codes [16] SER 10−1 10−2 10−3 10−4 10 12 14 16 SNR (dB) Figure SER vs SNR comparison of the proposed OFDM- CDMA scheme...

Ngày tải lên: 20/06/2014, 21:20

... Contents Preface Introduction to Cellular Systems vii Direct-Sequence Spread Spectrum Systems 13 The Mobile ChaMel and Diversity Reception in CDMA Systems 41 An Overview of IS-95 and cdma2000 57 5.1X-EV: ... Introduction to Cellular Systems Key Topics: Cell, mobile station, base station, PSTN, BSC, MSC, cluster, FDMA, TDMA, CDMA Overview: An overview of cellular telephony systems is provided in this ... Cellular telephony systems are radio systems that involve distributed transmission Therefore, rather than having a single transmitter service many different users over a wide area of coverage (e.g.,...

Ngày tải lên: 18/04/2014, 12:26

... space -time- frequency coded MIMO -OFDM systems using Chu sequences IEEE Trans Wireless Commun 7(4), 1195–1202 (2008) T Jiang, Y Wu, An overview: peak-to-average power ratio reduction techniques for OFDM ... band-limited OFDM systems IEEE J Sel Areas Commun 18(11), 2270–2277 (2000) doi:10.1109/49.895032 C Ciochina, F Buda, H Sari, An analysis of OFDM peak power reduction techniques for WiMAX systems, ... subcarriers simultaneously used by two MSs by Moverlap To avoid any pairing incompatibility, the two MSs need to transmit the same symbol structure over the overlapping spectral portion Based on the...

Ngày tải lên: 21/06/2014, 00:20

... codes [6] are adopted in Wideband CDMA as channelization codes, thanks to the orthogonality ensured by codes belonging to the same set, i.e., at a parity of their Spreading Factor (SF) OVSF codes ... error-floor in the BER curves of DS-CDMA systems Phase-coded spread spectrum multiple access systems, such as DS-CDMA, may be analyzed by modelling phase shifts, time delays, and data symbols as mutually ... multi-user communication systems, because it is a measure of the agreement between different codes, i.e., of the channel separation capability The same family of spreading codes may provide very...

Ngày tải lên: 21/06/2014, 03:20

... K that is around M/2 instead of all possible M’s Real -time computing refers to hardware and software systems that are subject to a real -time constraint The BigOh notation is well accepted for ... When the computational complexity of an algorithm is polynomial time instead of exponential time, that algorithm is feasible for real -time EURASIP Journal on Advances in Signal Processing 600 1.8 ... proposed scheme is O(NM), which is polynomial 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...

Ngày tải lên: 21/06/2014, 08:20

... [12], the spaces between pilots in the time domain are chosen according to coherence time Tc ≈ 9/16π fd [32] if the coherent time is defined as the time over which the correlation function is ... DS/SFH-CDMA systems for overlay systems, ” IEEE Transactions on Wireless Communications, vol 1, no 3, pp 448–455, 2002 S Kondo and L B Milstein, “Performance of mMulticarrier DS CDNA systems, ” IEEE ... driving noise in the MC-CDMA systems can be simultaneously estimated in real time Since the proposed method works EURASIP Journal on Advances in Signal Processing in the time domain, it can significantly...

Ngày tải lên: 21/06/2014, 08:20

... normalized gold codes [21] were used as spreading codes wi , the delay was chosen as δ = l + 1/2 , and v(n) was white The BER versus Eb / N0 performances of the MMSE and the minimum BER DS-CDMA systems ... Figure that the difference between the MMSE and minimum BER systems is very small when M = 31 It is seen that the overall performances of the systems are improved when M increases since more bandwidth ... part of the ith noise-free eye diagram at time instant n is defined as the real part of the noise-free signal at the output of the receiver filter ri (z) at time n when the desired signal is di (n)...

Ngày tải lên: 21/06/2014, 22:20

... we present the turbo space -time coded MIMOCDMA system model Section presents MMSE space -time receivers for coded MIMO-CDMA systems In Section 4, we present turbo space -time receivers that employ ... turbo codes The numerical results are discussed in Section 5, and Section concludes this paper TURBO SPACE -TIME CODED MIMO-CDMA SYSTEM A MIMO-CDMA system that employs turbo codes and space time ... rates are adopted for the PA and IA receivers Since full rate spacetime block codes are being used, the overall code rate of both systems is not affected, thus the puncturing pattern used determines...

Ngày tải lên: 21/06/2014, 23:20

... BSOR iterative method and makes use of the spreading codes directly is proposed; this enables its practical implementation in long-code CDMA systems (e.g., IS-95 and UMTS) where the cross-correlation ... Petroleum and Minerals REFERENCES [1] J G Andrews, “Interference cancellation for cellular systems: a contemporary overview,” IEEE Wireless Communications, vol 12, no 2, pp 19–29, 2005 [2] R M Buehrer, ... Letters, vol 11, no 2, pp 176–178, 2007 [8] A Kapur and M K Varanasi, “Multiuser detection for overloaded CDMA systems, ” IEEE Transactions on Information Theory, vol 49, no 7, pp 1728–1742, 2003 [9]...

Ngày tải lên: 22/06/2014, 00:20

... BSOR iterative method and makes use of the spreading codes directly is proposed; this enables its practical implementation in long-code CDMA systems (e.g., IS-95 and UMTS) where the cross-correlation ... Petroleum and Minerals REFERENCES [1] J G Andrews, “Interference cancellation for cellular systems: a contemporary overview,” IEEE Wireless Communications, vol 12, no 2, pp 19–29, 2005 [2] R M Buehrer, ... Letters, vol 11, no 2, pp 176–178, 2007 [8] A Kapur and M K Varanasi, “Multiuser detection for overloaded CDMA systems, ” IEEE Transactions on Information Theory, vol 49, no 7, pp 1728–1742, 2003 [9]...

Ngày tải lên: 22/06/2014, 06:20

... macroscopic subsystems known as compartments The range of applications of nonnegative systems and compartmental systems includes pharmacological systems, queuing systems, stochastic systems whose ... state variables represent probabilities , ecological systems, economic systems, demographic systems, telecommunications systems, and transportation systems, to cite but a few examples Due to the severe ... by equivalently representing the time- varying discrete -time system 2.10 as an autonomous discrete -time nonlinear system by appending another state to represent time Specifically, defining y k −...

Ngày tải lên: 22/06/2014, 11:20

... “High-rate codes that are linear in space and time, ” IEEE Transactions on Information Theory, vol 48, no 7, pp 1804–1824, 2002 V Tarokh, N Seshadri, and A R Calderbank, “Space -time codes for high ... Therefore, the service time of a packet can comprise at most L + transmission rounds Each transmission round includes the actual transmission time of the packet and the waiting time of an ACK signal ... to mitigate the outage 3.2 ARQ-based ROP We first define two types of PERs The overall achieved PER, j denoted by PERoverall , is defined as the probability that a class j packet is incorrectly received...

Ngày tải lên: 22/06/2014, 19:20