The unprecedented growth in the data demands requires the effective use of data offloading techniques in 5G networks. Machine type communication (MTC) foster this growing trend even further. This paper proposes a novel cooperative data offloading scheme with the help of multiple mobile relaying devices. The proposed scheme cooperatively aggregates data from surrounding MTC devices and transmits it to the base station. The paper also presents the framework for the selection of secured and trusted relays by using the concept of trust transitivity. The proposed relay scheme is compared with existing algorithms including mobile and stationary relay schemes. The simulation results show that our proposed scheme improves outage probability and communication delay by 33% and 25%, respectively as compared to fixed relay scheme.

Communication in 60-GHz frequency exhibits unique characteristics that are unavailable in traditional lower frequencies. Tremendous propagation loss together with oxygen absorption characteristics helps localize interference and encourages concurrent transmission. It is observed that in short-range, high-speed communication network, (Tx, Rx) pair tends to come close to each others. The network can be seen as naturally formed group of devices, which shared mutual interests. In Such networks, it is argued that throughput mainly depends on scheduling algorithms rather than transmission power control. In this paper, we proposed a concurrent scheduling algorithm based on vertex coloring technique. The proposed algorithm employs time and space division in scheduling in 60-GHz networks. Using vertex multi-coloring, we allow (Tx - Rx) communication pairs to span over more colors, enabling better time slot utilization. Since we use directional antennas, we extend distance based space division between two flows by considering angel between them. Since, data rate in 60-GHz mainly depends on transmission links, distance based relay selection algorithm is also proposed. We evaluate our scheduling algorithm in single-hop and multi-hop scenarios and discover that it outperforms traditional TDMA and greedy algorithm by significantly improving network throughput.

Networks based on 60-GHz promise data rates in gigabits and show least tolerance towards signal blockage. In addition to severe propagation loss, signal blockage may result in an attenuation upto 40dB. Distributed relay selection scheme is proposed in this paper to cater for signal attenuation. By maintaining a table containing details about interference measurements and neighboring devices, a receiver device determines an optimal relay for its active transmission. Furthermore, outage probability analysis is provided and is utilized to compare our proposed scheme with direct transmission and fixed node relay scheme. Simulation results show that our proposed scheme significantly improves outage probability and system throughput.

The world is witnessing a tremendous increase in data demands which is subject to the new emerging technologies, applications and services. 60 GHz communication network is one of such technology, claiming data rate in multi-gigabits. In this paper, we propose a scheduling algorithm for device-to-device 60 GHz network having directional antennas. The proposed algorithm utilizes the vertex coloring scheme and is optimized to improve system throughput. A threshold minimum distance between conflicting flows is used to keep the accumulative interference limited. Also, when there are conflicts among different flows, those with better data rate prospects will be scheduled priorly. Simulation results show that our scheme has brought significant improvement to system throughput almost by 19% and average flow number per slot is improved by 12%, as compared to other scheduling algorithms.

In this paper, we investigate the beam squint problems in 60 GHz mm-wave wireless communication beamforming process. To minimize the degree of beam squint we formulate the objective task into a constrained optimization problem and derived a phase improvement scheme based on IEEE 802.15.3c codebook. For further improvement of system performance, main response axis (MRA) alignment scheme is proposed, the direction of MRA can be adjusted alignment exactly in different frequencies and can achieve higher array antenna gain with a lower side lobe level (SLL) and it is more effective than the first schemes, but requires more phase shifters. In order to reduce the complexity of MRA alignment scheme, we proposed MRA alignment simplify scheme, the scheme only require 1/2 phase shifters has a negligible performance loss compared with the second scheme. Extensive simulations have demonstrated that the proposed three schemes can suppress beam squint, improves system throughput and performs better than the existing scheme.

A novel Multiple-input Multiple-output (MIMO) detection scheme based on orthogonal experimental design (OED) is proposed in this paper. By exploiting the initial solutions given by linear detection and non-linear detection algorithms, a searching subspace is constructed to obtain additional performance gain. Exhaustive searching method is optimal in the subspace, but with quite high complexity. Then OED, which is widely used in chemical experiments and statistics, is applied to reduce the computational complexity. The minimal required complexity of OED-MIMO is only 6.25% needed but just with insignificantly performance lost compared with exhaustive method for the 8×8 MIMO system and 16-QAM modulation scheme. The proposed OED-MIMO scheme provides nearly 10 dB gain compared with MMSE and 5 dB gain with ZF-VBLAST.

Recently, the performance bounds of the compressed sensing (CS) recovery algorithms have been investigated in the noisy setting. However, most of the papers only focus on the noisy measurement model where the signal is noiseless and the noise enters after the CS operation. The noisy signal model where both the signal and the compressed measurements are contaminated by the different noises is not considered. This paper works on the noisy signal model and provides the performance bounds for the following popular recovery algorithms: thresholding and orthogonal matching pursuit (OMP), Dantzig selector (DS) and basis pursuit denoising (BPDN). The performance of the recovery algorithms is quantified as the ℓ2distance between the reconstructed signal and the true noisy signal. Next, the impacts of the noise are analyzed on the basis of the quantified performance. The analysis results show that the effective way to restrain the impact of the noise is to choose the measurement matrix with low correlation between the columns or the rows. Finally, the theoretical bounds are verified with numerical simulations by calculating the mean-squared-error for the different noise variances. The simulation results show that OMP owns the better performance than the other three recovery algorithms under the noisy signal model.

Frequency reuse (FR) has been widely deployed to achieve increased throughput and interference mitigation. Different FR schemes can prove to be efficient under different conditions and parameters. This paper formulates a generic mathematical model which can be used to obtain an FR scheme that can be tailored according to our requirements. The paper proposes a fuzzy set theory based generic mathematical model for deriving various Soft Fractional FR (SFFR) schemes. The derived schemes are evaluated using various parameters such as average throughput, spectral and power efficiency. To the best of our knowledge, the use of fuzzy set theory for deriving different SFFR schemes is the first effort that can be found in the literature. The analysis provided in the paper discovers an optimal SFFR scheme which provides higher spectral efficiency and throughput. Our proposed scheme, at FR =1.35, improves the power efficiency (8.68 Watts/(bps/Hz)) by staggering 21% and 57% as compared to FR=1 (11 Watts/(bps/Hz)) and FR=3 (20 Watts/(bps/Hz)), respectively.