On optimizing FER target for cdma2000 downlink

Multiband simultaneous transmission (MST) system has been studied to enhance the spectral efficiency of wireless local area network (WLAN). In this system, information bits are divided into multiple bands and appropriately modulated taking account for the channel condition of each frequency band, and then a transmission frame consists of differently modulated symbols. To achieve higher spectrum efficiency, it is important to select an appropriate modulation and coding scheme satisfying an allowable frame error rate (FER). It means that FER prediction is a key technique to avoid low rate transmission and the frequent frame error. In this paper, we propose a FER prediction method for MST system. To predict the FER, we derive pairwise error probability (PEP) for this system. Moreover, we also consider the FER calculation based on the PEP for the WLAN system with a block interleaver. Furthermore, in order to improve prediction accuracy, we consider the impact of symbol error occurring beyond adjacent symbols on the PEP derivation. The simulation results show the accuracy of the proposed FER prediction method for both the additive white Gaussian noise channel and a multipath channel.

Continuous variable quantum key distribution (CV-QKD) allows the distribution of symmetric keys in a secure manner. CV-QKD systems can extract keys at its maximum rate when using Gaussian modulation (GM). Nonetheless, GM demands high-capacity random number sources and tends to be very hard to approach in practice. To circumvent these disadvantages, higher-order probabilistic -shaped discrete modulation (DM) can be used. State-of-the-art works compute the key rates of DM-CV-QKD systems considering a fixed value for the reconciliation efficiency and do not take into account the frame error rate (FER) of the system, thus over or under estimating the key rates. In this work, we study the security bounds of CV-QKD systems considering probabilistic shaped DM formats with 256-symbols in the finite-size regime. This accounting for the true value of the reconciliation efficiency, and the FER of the information reconciliation step. Both conventional and hexagonal 256-quadrature amplitude modulation (QAM) constellations yield higher key rates than 256-amplitude and phase shift keying (APSK) constellations, with 256-QAM constellations being indistinguishable in performance with GM for high transmission distances. Minimum signal-to-noise ratio (SNR) values were fixed from a FER analysis through a CV-QKD simulation allowing for key extraction considering different FER levels. Lower FER values are associated with higher SNRs in the system and thus lower achievable transmission distances. Nonetheless, the FER maximizing the extraction key rate is not null. Our results show that the extraction key rate is maximized by SNR adjustment which should have in account both the reconciliation efficiency and the FER.

Future automation and control units for advanced driver assistance systems (ADAS) will exchange sensor and kinematic data with nearby vehicles using wireless communication links to improve traffic safety. In this paper we present an accurate real-time system-level simulation for multi-vehicle communication scenarios to support the development and test of connected ADAS systems. The physical and data-link layer are abstracted and provide the frame error rate (FER) to a network simulator. The FER is strongly affected by the non-stationary doubly dispersive fading process of the vehicular radio communication channel. We use a geometry-based stochastic channel model (GSCM) to enable a simplified but still accurate representation of the non-stationary vehicular fading process. The propagation path parameters of the GSCM are used to efficiently compute the time-variant condensed radio channel parameters per stationarity region of each communication link during run-time. Five condensed radio channel parameters mainly determine the FER forming a parameter vector: path loss, root mean square delay spread, Doppler bandwidth, <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">K</i> -factor, and line-of-sight Doppler shift. We measure the FER for a pre-defined set of discrete grid points of the parameter vector using a channel emulator and a given transmitter-receiver modem pair. The FER data is stored in a table and looked up during run-time of the real-time system-level simulation. We validate our methodology using empirical measurement data from a street crossing scenarios demonstrating a close match in terms of FER between simulation and measurement.

A closed loop power control (CLPC) with linear prediction at a base station has been investigated for the reverse link in a code division multiple access (CDMA) system. Several algorithms, e.g., Durbin-Levinson (DL), least minimum square error (LMS), recursive least square (RLS), and Burg, are applied to predict the received signal bit energy to interference power spectral density (Eb/Io) at a base station with a finite impulse response (FIR) filter. It is observed that with perfect channel estimation, the simulation results show that 1 dB improvement in Eb/Io can be made at a certain frame error rate (FER), compared to the existing IS-95 closed loop power control scheme. However, with practical channel estimation obtained by employing these prediction algorithms, insignificant FER improvement is observed. The group delay introduced by a prediction algorithm is a major reason to cause the insignificant improvement.

CDMA systems have a trade-off relationship between the frame error rate (FER) and the number of accepted users. Therefore, the call admission control (CAC) scheme is essential for guaranteeing the FER below the required value, which is the measure of the quality of service (QoS) in the frame level. In cellular networks, the dropping probability of handoff calls is another critical measure for QoS in the call level. There has been, nevertheless, little concern for CAC schemes guaranteeing these QoS requirements simultaneously in the CDMA cellular networks. In this paper, we propose CAC that track the time-varying capacity of CDMA systems by estimating the distribution of the total received power at a base station, thereby realizing the bandwidth reservation scheme to meet the QoS requirement for handoff calls in the call level.

We propose an analytic model to compute the station's saturated throughput and packet delay performance of the IEEE 802.11 DCF (Distributed Coordination Function) in which frame transmission error rates in the channel are different from each other. Our analytic model shows that a station experiencing worse frame error rates than the others suffers severe performance degradation below its deserved throughput and delay performance. 802.11 DCF adopts an exponential back-off scheme. When some stations suffer from high frame error rates, their back-off stages should be increased so that others get the benefit from the smaller collision probabilities. This impact is then recursively applied to degrade the performance of the victim stations. In particular, we show that the performance is considerably degraded even if the frame error rate of the victim station satisfies the receiver input level sensitivity that has been specified in the IEEE 802.11 standard. We also verify the analytic results by the OPNET simulations.

The attainable Frame Error Rate (FER) in satellite burst communication is much too high when a classical Costas Loop is used as the carrier synchronizer. This high FER is due to cycle slips and hang-up of the Costas Loop. We demonstrate the potential to achieve a FER of 3×10-6 using 3 parallel Kalman tracking loops with their initial frequencies spaced apart. We also propose an algorithm for selecting the correct loop for demodulation and use data aided and optimal phase detection for the preamble and payload respectively. This dramatic improvement is at a reasonable complexity.

The paper presents a novel cooperative coding scheme using punctured serial concatenated convolutional codes (SCCC). We evaluate its performance in terms of frame error rate (FER) under two cooperation protocols: a decode-and-forward protocol in conjunction with automatic repeat request (ARQ), by which the relay sends an acknowledge bit (ACK) back to the source to indicate whether its data packet is correctly decoded; an adaptive amplify-and-forward protocol, where the amplifying relay node cooperates to forward the message only when the inter-user link gain is above a certain threshold. In both cases, the destination makes the decision on each transmitted bit after appropriately combining signals and performing iterative decoding. Simulation results show that SCCC-based cooperative coding achieves full spatial diversity and exhibits a similar FER performance to that using parallel concatenated convolutional codes (PCCC). At the price of channel feedback, the adaptive decode-and-forward algorithm demonstrates a relatively lower FER than the adaptive amplify-and-forward scheme. Amplified cooperation experiences severe performance degradation due to the inefficiency of repetition coding and error propagation, especially when the quality of the source-relay link deteriorates; however, if the threshold for carrying cooperation is carefully selected, the adaptive amplify-and-forward protocol can perform comparably to the decode-and-forward protocol.

Low-density Parity check codes (LDPC) are gaining interest for high data rate application in both terrestrial and spatial communications which requires low bit error rate. This paper proposes an algorithm through which the best parity check matrix is obtained for irregular low density parity check codes, which reduces the Bit Error Rate ,Frame Error Rate and computational complexity. Tanner graph also called a bipartite graph format in an Low Density Parity Check (LDPC) code design contains many short cycles; it will produce a computational complexity in a code design process and it degrades the code performance. To overcome this effect, we proposed an new algorithm which obtains a best final parity check matrix. Throughout the paper we will give the detailed description of an efficient algorithm proposed. The complexity is studied graphically and analytically. Using proposed algorithm, cycles of length four observed in corresponding matrix are removed. Each matrix is evaluated over a noisy Additive White Gaussian Noise (AWGN) channel. Bit Error rate and Frame error rate is calculated. The results are compared with randomly generated best parity check matrix. Simulation results shows that proposed method successfully overcomes the computational complexity and meets the near Shannon limit.

This paper presents a novel and cost effective method to be used in the optimization of the Gaussian Frequency Shift Keying (GFSK) at the receiver of the Bluetooth communication system. The proposed method enhances the performance of the noncoherent demodulation schemes by improving the Bit Error Rate (BER) and Frame Error Rate (FER) outcomes. Linear, Extended, and Unscented Kalman Filters are utilized in this technique. A simulation model, using Simulink, has been created to simulate the Bluetooth voice transmission system with the integrated filters. Results have shown improvements in the BER and FER, and that the Unscented Kalman Filters (UKF) have shown superior performance in comparison to the linear Kalman Filter (KF) and the Extended Kalman Filter (EKF). To the best of our knowledge, this research is the first to propose the usage of the UKF in the optimization of the Bluetooth System receivers in the presence of additive white Gaussian noise (AWGN), as well as interferences.

We explore discriminative training of HMM parameters that directly minimizes the expected error rate. In discriminative training one is interested in training a system to minimize a desired error function, like word error rate, phone error rate, or frame error rate. We review a recent method (McAllester, Hazan and Keshet, 2010), which introduces an analytic expression for the gradient of the expected error-rate. The analytic expression leads to a perceptron-like update rule, which is adapted here for training of HMMs in an online fashion. While the proposed method can work with any type of the error function used in speech recognition, we evaluated it on phoneme recognition of TIMIT, when the desired error function used for training was frame error rate. Except for the case of GMM with a single mixture per state, the proposed update rule provides lower error rates, both in terms of frame error rate and phone error rate, than other approaches, including MCE and large margin.

Increasing the performances of turbo codes used in communication systems is an important issue at the moment. The method used for trellis termination influences the code performances. This paper describes and compares (in terms of bit error rate - BER and frame error rate - FER) four types of these methods: without trellis termination, termination only of the first trellis, post-interleaver flushing and dual termination. Turbo code performances are evaluated for two lengths of S-random interleaver, using binary phase-shift keying (BPSK) modulation, over Additive White Gaussian Noise (AWGN) channel. The simulations were performed for two generating matrices of the component encoders and the decoding algorithm we have used is a version of Max-Log-MAP.

We present an optimization architecture for a cross- layer design in wireless video transmission and investigate the multicarrier effect on wireless communication. To transmit video frames constrained by delay bound and target frame error rate (FER), we formulate an optimization problem to minimize the required resource units for a single user by adapting payload length, M-ary modulation, block size, and code rate. Instead of using exhaustive approach, we propose a minimal required resource units (MRRU) algorithm with feedback of mean mutual information per bit (MMIB) to resolve this problem by binomial distribution function approximation. Finally, the performance comparison between MRRU algorithm and maximum throughput approach is given, and the effect on multicarrier system in a correlated Rayleigh fading channel is shown.

Polar codes under cyclic redundancy check-aided successive cancellation list (CA-SCL) decoding can outperform the turbo codes and the LDPC codes when code lengths are configured to be several kilobits. In order to reduce the decoding complexity, a novel tree-pruning scheme for the SCL/CA-SCL decoding algorithms is proposed in this letter. In each step of the decoding procedure, the candidate paths with metrics less than a threshold are dropped directly to avoid the unnecessary computations for the path searching on the descendant branches of them. Given a candidate path, an upper bound of the path metric of its descendants is proposed to determined how much pruning this candidate path would affect frame error rate (FER) performance. By utilizing this upper bounding technique and introducing a dynamic threshold, the proposed scheme deletes as many as possible of the redundant candidate paths while keeping the performance deterioration in a tolerant region, thus it is much more efficient than the existing pruning scheme. With only a negligible loss of FER performance, the computational complexity of the proposed pruned decoding scheme is only about 40% of the standard algorithm in the low signal-to-noise ratio (SNR) region (where the FER under CA-SCL decoding is about 0.1 ~ 0.001), and it can be very close to that of the successive cancellation (SC) decoder in the moderate- and high-SNR regions.

In this study, the authors introduce adaptive modulation and coding in a two‐way amplify‐and‐forward (AF) relay network to improve the system performance. They consider a cooperative system where two user nodes exchange information with the assistance of multiple two‐way AF relays. In the proposed scheme, the user nodes adaptively choose the appropriate modulation and coding scheme to ensure that the frame error rate (FER) satisfies the system requirement; all relays are utilised to forward the received signals to the user terminals. Furthermore, they provide a better approximation of the cumulative distribution function of the destination signal‐to‐noise ratio; and thus, derive more accurate expressions including average spectral efficiency and average FER in closed‐form, over Rayleigh fading channels. The theoretical analysis is verified by numerical results.