Pitch accuracy and rhythm errors are the most common problems encountered by erhu beginners. The traditional way of learning the erhu involves using a tuner and a metronome to improve these two issues. However, for erhu beginners, without the assistance of a teacher, it is often difficult to address these problems effectively. Therefore, this study has developed an "Intelligent Personalized Erhu Pitch and Rhythm Learning System" to help erhu learners learn to pitch and rhythm anytime and anywhere without the presence of a teacher while providing professional feedback. This system included pitch and rhythm training features. In addition to automatically generating sheet music in the MML (Music Macro Language) format, it allows the erhu learners to play along with the sheet music. After each performance, the system provides learners with expert-like comments on pitch and rhythm, respectively. The system also keeps a record of learners' practice sessions and provides appropriate encouragement and guidance based on their learning progress by creating an intelligent and personalized learning scaffold. After the development of the system, this study conducted a usability evaluation and investigated the relationship between usability and erhu playing experience. The results showed that the average for all usability dimensions was above 4.6, indicating that the system is acceptable for erhu learners. Moreover, learners with more erhu playing experience showed higher acceptance of the system compared to those with less experience in erhu.

This study investigates channel estimation for amplify‐and‐forward (AF) relaying systems. For a two‐hop relaying system, channel estimation of a relay path (source–relay–destination) with AF relaying is unique because both individual source‐to‐relay (S–R) and relay‐to‐destination (R–D) links are necessary at the destination to perform the optimum combination of signals received from the direct path (source‐to‐destination) and relay path if employing a cooperative diversity transmission. Until now, most literature about channel estimation on relaying systems has focused on the composite channel of the relay path, and not its individual links. Current methods to separate the estimation of both individual links require the relay to either deliver a quantised version of the S–R link estimate through an independent feed‐forward channel, or to perform discrete Fourier transform/inverse discrete Fourier transform operations before amplifying the received signals. In this study, the respective channel estimations are done at the destination. First, the destination utilises a relay amble (R‐amble) to obtain channel estimation of the R–D link. Next, exploiting the R–D link estimate, a maximum‐likelihood estimator is proposed for the S–R link in a decision‐directed (DD) way. Simulation results show that the proposed scheme out performs the current relay‐assisted methods in most circumstances. In addition, numerical results reveal that the mean‐square error can be significantly reduced in a DD way for symbol error rates of interest.

In this paper, we propose a novel reduced-complexity Jacobian radial basis function (RBF)-assisted decision-feedback equalizer (DFE)-based turbo equalization (TEQ) scheme based on the modified Bayesian conditional probability density function. The proposed reduced-complexity Jacobian RBF DFE TEQ is capable of providing a near-identical performance to the Jacobian RBF DFE TEQ at a lower computational load in the context of both binary phase-shift keying (BPSK) and 4 quadrature amplitude modulation (QAM). When the channel impulse response (CIR) length is 3, in the subsequent iterations after the first iteration, the reduced-complexity Jacobian RBF DFE TEQ achieves the addition/subtraction reduction factors of 1.69 and 3.39 and the multiplication/division reduction factors of 1.14 and 2.46 when compared to the Jacobian RBF DFE TEQ for BPSK and 4 QAM, respectively. When the CIR length is 4, the addition/subtraction reduction factors of 3.6 and 14.9 and the multiplication/division reduction factors of 2 and 9.14 are attained for BPSK and 4 QAM, respectively. These are achieved by utilizing the a priori data provided from the channel decoder to reduce the number of the desired channel output states and to simplify each distance evaluation between each desired channel output state and the observed channel output vector in the subsequent iterations.

An ant colony optimisation (ACO)-based multiuser detector assisted by spatial diversity reception using direct-sequence CDMA is proposed. By taking advantage of heuristic values and the collective intelligence of ACO, the proposed detector offers almost the same bit error rate (BER) performance as the full-search-based optimum multiuser detector does, while greatly reducing the computational complexity. The near–far resistance of the ACO-based multiuser detector is also examined. The BER performance for a ten-user system deteriorates scarcely when the interfering users’ energy is 12 dB higher than that of the desired user.

Previous turbo equalization (TEQ) research has shown that the Jacobian radial basis function (RBF) decision-feedback equalizer (DFE) TEQ scheme considerably reduces computational complexity compared to the logarithmic maximum a posteriori (Log-MAP) TEQ with similar performance. In this paper, we propose a new reduced-complexity RBF-assisted DFE-based TEQ scheme using a novel extended fuzzy c-means (FCM) algorithm. The proposed reduced-complexity RBF DFE TEQ not only greatly reduces computational complexity but also offers similar performance in contrast to the Jacobian RBF DFE TEQ. With this, the materialization of the TEQ scheme becomes more feasible.

A noncollision packet reservation multiple access with dynamic allocation (NC-PRMA/DA) scheme is proposed and investigated as a suitable candidate protocol for wireless multimedia communications. Access requests of the existing users in NC-PRMA/DA are conveyed to the base station in a noncollision manner by using a time-frequency signaling scheme. In addition, the scheduling NC-PRMA/DA (SNC-PRMA/DA) scheme, which is NC-PRMA/DA with packet scheduling, is also presented. Mixed voice, variable-rate video, and data traffic is used to demonstrate the efficiency of the proposed schemes for a single-cell environment. Simulation results show that our proposed NC-PRMA/DA and SNC-PRMA/DA protocols outperform the existing PRMA/DA protocol.

A joint code division multiple access and noncollision packet reservation multiple access (CDMA/NC-PRMA) technique is proposed and investigated as an uplink protocol for the third-generation (3G) mobile systems. Being the underlying time division multiple access (TDMA) architecture of the CDMA transmissions, NC-PRMA enables the base station (BS) to have a centralized control over the slot allocation policy. In order to reduce the multiple access interference (MAI) variation in a CDMA transmission, two different slot assignment schemes, referred to as load-balancing (LB) and power-grouping (PG) schemes, are proposed and evaluated. Simulation results show that considerable improvement can be achieved over the joint CDMA/PRMA scheme, in which the MAI variation is reduced by way of a dynamic permission probability for contending terminals. Especially when an imperfect power control mechanism is considered, the proposed PG assignment scheme achieves significant performance advantages.