3G WCDMA design, simulation and analysis using ptolemy software tools

This research aims to use the Adaptive Minimum Bit Error Rate (AMBER) for Wideband Code Division Multiple Access (WCDMA). AMBER and Normalized AMBER (NAMBER) algorithms for WCDMA systems are derived and implemented. Its Bit Error Rate (BER) performance is measured using a WCDMA Frequency Division Duplex (FDD) Downlink Physical Layer model. The new methods are compared to the original WCDMA system and the NLMS Adaptive Combiner. Results show around 5 dB performance gain over the single antenna system, and around 2 dB performance gain over the Dual Antenna Normalized Least Mean Squares (NLMS) Adaptive Combiner system in an Additive White Gaussian Noise channel at a BER of 10-2.5. However, complex computation requirements render the algorithms impractical for widespread use. Simplifications and alternative implementations have to be investigated.

Wavelets are being utilized in various communications applications either as an alternative to short time Fourier transform for spectral analysis of non-stationary data or as a new tool to bridge between time domain and frequency domain analysis. A wavelet-based algorithm for image compression with four levels of unequal error protection (UEP) codes over wide-band code division multiple access (W-CDMA), additive white Gaussian noise (AWGN) and Rayleigh fading channels are analyzed. The utilization of wavelets has come out to be a powerful method for compress images. The wavelet transform compression technique has shown to be more appropriate to low bit rate applications, producing better quality output for the compressed frame of video. The proposed algorithms of the 2-D wavelet packet transform (2-D WPT) and the embedded zero-tree wavelet (EZW) coder are investigated.

The WiMax (Worldwide Interoperability for Microwave Access) is a technology in<strong> </strong>broadband wireless access, which employs OFDM (Orthogonal Frequency Division Multiplexing) as an alternative transmission to enable high speed data in communication system. This research aim is to analyze the performance system of the OFDM-Based WiMAX, which used the cyclic prefix. The model was designed in four schemes of simulation method, the BPSK (Binary Phase Shift Keying, QPSK (Quadrature Phase Shift Keying), 16 QAM (Quadrature Amplitude Modulation) and 64 QAM. Each scheme was investigated BER (Bit Error Rate) on AWGN (Additive White Gaussian Noise) channel and multipath Rayleigh fading channel, which had applied the cyclic prefix. By simulation of the cyclic prefix was produced the modulation measurement of the BPSK, QPSK, 16 and 64 QAM. The performance result of Eb/No 15 dB was obtained the BER of BPSK and QPSK of 1.11E-11, the BER of 16 QAM and 64 QAM of 8.69E-06 and 0.00333 respectively. Those results indicated much smaller BER value than EbNo 0 dB which BPSK and QPSK of 1 BER, 1.5 and 1.75 BER for 16 QAM and 64 QAM respectively. In conclusion, a higher value of EbNo, hence the BER value would be lower.

Performance of both orthogonal frequency division multiplexing (OFDM) and single carrier (SC) systems suffers from a carrier frequency offset (CFO) due to Doppler effect and the carrier instability between the transmitter and the receiver. We investigate the bit error rate (BER) performance degradation of OFDM and SC systems due to the frequency offset in an additive white Gaussian noise (AWGN) channel as well as multipath Rayleigh fading channels. We consider three effects to the BER degradation, i.e., phase shift, useful power decrease and intercarrier interference (ICI). We also derive the approximate expressions of BER under binary phase shift keying (BPSK) and quaternary phase shift keying (QPSK) for both OFDM and SC systems in the presence of CFO. In general, SC is more robust to CFO in the AVVGN channel than OFDM in terms of BER, while both of them suffer similarly from CFO in the multipath Rayleigh fading channels assuming the the same CFO.

In this paper, a novel coded modulation scheme named Trellis-Coded Differential Chaotic Modulation (TC-DCM) is proposed, which combines trellis codes with M-ary Differential Chaotic Shift Keying (M-DCSK). The new scheme not only reduces the multipath interference efficiently due to its inherent spreading property, but also avoids the use of Channel State Information (CSI), exact synchronization, despreading and the Rake receiver, making the corresponding receiver design simpler and more suitable for band-limited communication systems under severe multipath propagation conditions. Analytical Bit-Error-Rate (BER) bounds are derived and verified over Additive White Gaussian Noise (AWGN) channels. Both analytical performances and simulation results show that the proposed scheme with different states and different coding rates can obtain significant coding gains, compared to the corresponding uncoded schemes with the same bandwidth over AWGN channels. In addition, it is found from simulations that over multipath Rayleigh fading channels without CSI, the proposed TC-DCM system outperforms the Trellis-Coded Modulation Direct-Sequence Spread-Spectrum (TCM DS/SS) system with the same bandwidth efficiency.

In this paper, a power allocation strategy is applied to improve the bit-error-rate (BER) performance of M-ary code shifted differential chaos shift keying system (GCS-MDCSK) system. Particularly, different power coefficients are allocated for the reference and information bearing signals of GCS-MDCSK system, respectively. Moreover, the theoretical BER expressions of GCS-MDCSK system with power allocation strategy are derived over additive white Gaussian noise (AWGN) and multipath Rayleigh fading channels. Then, the optimal power ratio of reference and information bearing signals is deduced by finding the minimum of BER expression. Finally, the BER performance of the optimized GCS-MDCSK system is compared to ordinary GCS-MDCSK and other chaotic communication systems. Numerical results confirm the preferable BER performance of the optimized GCS-MDCSK system.

In this paper, we study the effects of channel estimation error on the bit error rate (BER) of orthogonal frequency division multiplexing systems in multipath Rayleigh fading channels. Due to the additive white Gaussian noise and the intercarrier interference caused by the residual carrier frequency offset, the channel estimation based on the training symbols is not perfect. We characterize the performance degradation resulting from imperfect channel state information by deriving the BER formulas for BPSK, QPSK, and 16-QAM modulation schemes. Simulation results validate the accuracy of our derived formulas.

The performance analysis of polarization M-ary differential chaos shift keying (P-MDCSK) has been expressed using a tight upper bound with the Q-function. However, evaluating the Q-function directly is not a closed expression and there has been less work on closed expression for the upper bound. In order to solve the problem, this paper presents approximate closed-form expressions on the error probability of P-MDCSK. This expression is derived by employing a polynomial approximation of the Q-function. These closed-form expressions are verified through simulations conducted under both additive white Gaussian noise (AWGN) and multipath Rayleigh fading channels. The simulation results reveal that there exists only a negligible gap between the simulations and the derived closed-form expressions. For example, it is observed that the theoretical approximate closed-form expressions exhibit a marginal deviation of approximately dB from the simulations when the bit error rate (BER) reaches . Although the proposed method can only give approximate closed-form expressions of the upper bound, it provides an effective method for other communication schemes where the exact BER closed-form formula cannot be obtained.

In this letter, a non-coherent discrete W transform based index-keying M-ary differential chaos shift keying (DWT-IK-MDCSK) system is proposed to tackle the high peak to average power ratio (PAPR) in the code-shifted DCSK systems and meet the demand of high-data-rate transmissions. In such system, multiple chaotic signals and their Hilbert transforms are cooperated closely to convey the M-ary information-bearing signals, and the resultant signals are extended by the index-keying discrete W vectors prior to being added up and transmitted over the channel. Since the index keying technique is used to select the specific discrete W vectors, extra information bits are conveyed by the indices of these vectors, thereby improving the data rate. Then, the analytical bit error rate (BER) expressions of DWT-IK-MDCSK are derived over additive white Gaussian noise (AWGN) and multipath Rayleigh fading channels. Finally, simulation results show the DWT-IK-MDCSK system has a lower PAPR and better BER performance compared to its competitors.

In this paper, a novel coupled code shifted M-ary differential chaos shift keying modulation scheme is proposed as a simple and low-cost solution to reference removal. In this scheme, only two information-bearing signals are transmitted. Both signals are modulated by selected Walsh code sequences with specific indices determined by the index bits, and one of them also carries an additional M-ary information symbol. Since these two information-bearing signals are coupled by the same chaotic message bearer, data bits can be easily recovered according to the correlation between these two signals so that the transmission of reference signals can be completely avoided. Theoretical Bit Error Rate (BER) expressions are derived over the additive white Gaussian noise and multipath Rayleigh fading channels. Furthermore, simulations and comparisons indicate that the proposed system can achieve better BER performance with lower complexity.

This paper presents the performance analysis of compound chaotic sequence (CCS)-based noise reduction differential chaos shift keying (NR-DCSK) system under multipath Rayleigh fading channel conditions. The special characteristics of chaotic sequences are their deterministic randomness behaviour that adds security and multipath immunity to the data when used as a carrier in communication systems. In this paper, the chaotic sequences are generated by combining the outputs of chaotic maps, such as logistic map, Chebyshev map, Bernoulli shift map, tent map, etc., leading to new complex sequences known as CCSs. This sequence possesses more randomness, overcomes severe interference levels encountered during transmission and provides higher multipath immunity compared with those of pseudo-noise (PN) codes. Since NR-DCSK is a spread spectrum technique, its performance in wireless multipath fading channels has important considerations. The CCS is used as a carrier in NR-DCSK systems, which leads to improved bit error rate (BER) performance. Comparisons of simulation results to theoretical BER expressions of additive white Gaussian noise (AWGN) and Rayleigh fading channels have been carried out to test the efficiency of the proposed CCS-based NR-DCSK system.

Coherent reception of quadrature phase-shift keying (QPSK) modulated signals in an uplink channel of a direct-sequence code-division multiple access (DS-CDMA) system is considered. The receivers, commonly referred as the conventional matched-filter receiver and the RAKE receiver, are analyzed when the transmission of data is performed over the additive white Gaussian noise (AWGN) channel and the multipath slow Rayleigh fading channel, respectively. Both analyses take into account inaccuracies in the carrier phase estimations resulting from a carrier phase estimator.

The high altitude platform station (HAPS) system is considered as one of the most effective solutions to provide high quality wireless communication services, such as IMT-2000 services. In this paper, we provide a method to estimate the reverse link capacity of the wideband code division multiple access (WCDMA) system using HAPS, and demonstrate the results. HAPS would be located at 17 km to 22 km above sea level with a multi-beam antenna system and it leads to a consideration of new channel conditions and system design criteria different from those of the conventional terrestrial system. Therefore, we use a practical system model which represents the HAPS system most appropriately, and it leads to realistic estimation results. We estimate the reverse link capacity of the RAPS WCDMA system considering a multi-cell and multi-HAPS model and compare it to that of the conventional terrestrial system. The estimation results show that the capacity in the border cells is decreased and the capacity of the HAPS WCDMA system is about 1.2 to 1.67 times larger than that of the conventional terrestrial system.

In this work, we first provide an overview of the state of the art in mismatch error estimation and correction for time-interleaved analog to digital converters (TI-ADCs). Then, we present a novel pilot-based on-line adaptive timing mismatch error estimation approach for TI-ADCs in the context of an impulse radio ultra wideband (IR-UWB) receiver with correlation-based detection. We introduce the developed method and derive the expressions for both additive white Gaussian noise (AWGN) and Rayleigh multipath fading (RMPF) channels. We also derive a lower bound on the required ADC resolution to attain a certain estimation precision. Simulations show the effectiveness of the technique when combined with an adequate compensator. We analyze the estimation error behavior as a function of signal to noise ratio (SNR) and investigate the ADC performance before and after compensation. While all mismatches combined cause the effective number of bits (ENOB) to drop to 3 bits and to 6 bits when considering only timing mismatch, estimation and correction of these errors with the proposed technique can restore a close to ideal behavior. We also show the performance loss at the receiver in terms of bit error rate (BER) and how compensation is able to significantly improve performance.

The reverse link performance of direct sequence code division multiple access (DS-CDMA) system in wireless communication over a frequency selective multipath fading channel has been investigated in this paper. The channel has been modeled as Nakagami-m distributed frequency selective multipath fading channel. A conventional correlator type receiver has been considered for the analysis. Noise is taken as additive white Gaussian noise (AWGN) with two sided power spectral density N/sub 0//2 . To model multiple access interference (MAI), standard Gaussian approximation (SGA) has been considered in this paper. To mitigate the near-far problem, a power control scheme, but imperfect has been assumed in this paper. The bit error rate (BER) expression for the system has been derived and simulated by varying number of users, number of fading path, processing gain, fading parameter, SNR per bit E/sub b//N/sub 0/ and variation in the amplitude of the received signal. The analysis shows that as the number of simultaneous active user, the number of fading path and the variation in the power of the received signal increases, the BER of the system increases indicating the performance degradation. As the value of the processing gain, the ratio E/sub b//N/sub 0/ and the fading parameter increases, the BER performance of the system improves.