This paper investigates the communication performance of a sleeve dipole antenna used in the Rashid rover, part of the Emirates Lunar Mission, at a frequency of 2.42 GHz. The proposed antenna serves as the primary antenna in the Rashid rover, and its communication performance is evaluated through various scenarios using a simulated model. Initially, a stand-alone antenna was designed, and the results showed that the sleeve dipole antenna provides an omnidirectional radiation pattern and reasonable gain at 2.42 GHz. Subsequently, the model was developed using a simplified model of the lunar ground surface in which the performance of the antenna was evaluated. Finally, the antenna's performance was illustrated in the context of its location, which is close to the metallic mast of the rover which substantially affects antenna parameters. It was also observed that although the electrical properties of the lunar regolith had no significant effect on crucial antenna parameters such as operating frequency and bandwidth; placing the antenna closer to the lunar regolith causes modification in the pattern which results in a moderate increase in gain.

In this paper, several indoor positioning systems are reviewed and a deep neural network (DNN) algorithm based on Scaled Conjugate Gradient (SCG) algorithm is proposed. In the proposed indoor positioning system, Received Signal Strength (RSS) is used as a fingerprint to identify the indoor location in terms of Building and Floor. The performance of the system is evaluated and compared against other machine learning based positioning systems. The accuracy of the proposed DNN is 99% when tested using a standard dataset.

This paper develops a new wavelet-based visual tracking system for miniature aerial vehicle (MAV) system. The visual signals for visual tracking system is formulated based on using wavelet coefficients. The design uses multiresolution interaction matrix with half and details image to relate the time-variation of wavelet coefficients with the velocity of the MAV and controller. The design is evaluated on a quadrotor MAV system to demonstrate the effectiveness of the wavelet based 6-DOF visual tracking system without using image processing unit. The evaluation results show that the MWT based linear controller can provide accuracy and efficiency without using image processing unit provided that the system does not contain any uncertainty.

This paper presents a hybrid automatic repeat request (HARQ) system using a parity error checking (PEC) technique with low processing power requirements. The proposed technique is applied to extended turbo product codes (TPC) where the parity check bits used for extending the component codes of TPC, are exploited to replace the conventional cyclic redundancy check (CRC) error detection in HARQ systems. Consequently, the required processing power can be reduced substantially while the throughput is almost unchanged for long TPC codes, or increased for short TPC codes. The proposed PEC technique is also compared to the state-of-the-art syndrome error checking (SEC) as well as conventional CRC. Monte Carlo simulation results reveal that PEC- HARQ can provide equivalent throughput to SEC-HARQ and higher throughput than CR-HARQ systems. Moreover, numerical results show that the PEC technique has lower computational complexity than both SEC and CRC error detection. In particular cases, the complexity of the proposed system is reduced by more than 50% as compared to the state- of-the-art, and by more than 80% when compared to the CRC error detection.

This paper presents an adaptive power control scheme for hybrid automatic repeat request (HARQ) systems with no channel state information feedback. The power control process is developed by noting that the throughput of particular HARQ systems may exhibit a staircase behavior. In such scenarios, the throughput remains fixed for a wide range of signal-to-noise ratios (SNRs). Consequently, the transmit power can be reduced significantly while the throughput remains almost unchanged. The obtained results reveal that invoking power optimization algorithms can achieve a significant power saving of about 80% for particular scenarios. The system considered in this work is a truncated HARQ with turbo product codes (TPC). Chase combining is also used to combine the retransmitted packets with the original transmission. HARQ acknowledgment/negative acknowledgment (ACK/NACK) feedback is used to estimate the packet error rate from which the system throughput is computed.

This paper presents a hybrid automatic repeat request (HARQ) system using turbo product codes (TPC). The inherent word-error detection capability of TPC is exploited to replace the conventional cyclic redundancy check (CRC) used for packet error detection in conventional HARQ systems. Therefore, TPC are used for joint bit error correction and packet error detection. Consequently, the HARQ system efficiency is improved by increasing the system throughput when short packets are transmitted or by reducing the computational complexity/delay when the packets transmitted are long. Monte Carlo simulation results reveal that the CRC-free TPC-HARQ system consistently provides equivalent or higher throughput than CRC-based HARQ systems. Moreover, numerical results show that TPC self-detection has lower computational complexity than CRC detection, particularly for TPCs with high code rates. In particular scenarios, the relative complexity of the self-detection approach with respect to popular CRC techniques is about 0.3%.

Hierarchical quadrature amplitude modulation (HQAM) enables unequal priority transmission through the use of non-uniformly spaced constellations. In this paper, we propose an adaptive HQAM (A-HQAM) scheme where the ratios between the constellation distances are regularly adjusted based on the channel condition with the objective of maximizing the transmission efficiency. The source bit stream is divided into multiple sub-streams which are simultaneously transmitted, each on a different priority level. When using A-HQAM, the high priority sub-stream maintains an acceptable bit error rate performance over all channel conditions. As the channel condition improves, the required protection for the high priority sub-stream is reduced allowing for increasing the protection level of lower priority sub-streams. Hence, the number of sub-streams with acceptable BER performances is incrementally increased as the channel condition improves. Analysis and simulation results show that the proposed A-HQAM not only enhances the transmission efficiency but also provides reduced peak to average power ratio (PAPR). The proposed scheme offers reduced complexity by using one constellation size, unlike conventional adaptive schemes which require the use of several constellation sizes. Moreover, a practical A-HQAM implementation is presented which enables the receiver to successfully demodulate the received signal without knowing the varying transmission parameters.

Delivery of multimedia contents over unreliable channels poses several challenges. In particular, video streaming has strict requirements on bandwidth, delay, and loss rate. In this paper, we propose the integration of several approaches to overcome these challenges. These approaches are adaptive modulation, adaptive channel coding, adaptive playback, and bitstream switching. The proposed adaptive scheme significantly improves the effective channel bitrate. It also accommodates variations in the channel condition and subsequently ensuring uninterrupted video playback.