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Data offloading plays an important role for the mobile data explosion problem that occurs in cellular networks. This paper proposed an idea and control scheme for offloading vehicular communication traffic in the cellular network to vehicle to vehicle (V2V) paths that can exist in vehicular ad hoc networks (VANETs). A software-defined network (SDN) inside the mobile edge computing (MEC) architecture, which is abbreviated as the SDNi-MEC server, is devised in this paper to tackle the complicated issues of VANET V2V offloading. Using the proposed SDNi-MEC architecture, each vehicle reports its contextual information to the context database of the SDNi-MEC server, and the SDN controller of the SDNi-MEC server calculates whether there is a V2V path between the two vehicles that are currently communicating with each other through the cellular network. This proposed method: 1) uses each vehicle's context; 2) adopts a centralized management strategy for calculation and notification; and 3) tries to establish a VANET routing path for paired vehicles that are currently communicating with each other using a cellular network. The performance analysis for the proposed offloading control scheme based on the SDNi-MEC server architecture shows that it has better throughput in both the cellular networking link and the V2V paths when the vehicle's density is in the middle.

This paper proposed a control scheme for offloading vehicular communication traffic from the cellular network to V2V paths that can exist in Vehicular Ad Hoc Networks (VANETs). The Software Defined Network (SDN) architecture is adopted to tackle the complicated issues of VANET V2V offloading. The performance analysis for the proposed SDN-based offloading control scheme shows that it has better throughput in both the 4G link and the V2V paths when vehicle's density is in the middle.

Using the non-equilibrium Green’s function and anti-bonding orbital model, a multiband treatment of quantum transport in an anisotropic semiconductor (Si-based) system is developed. In this study, we adopt Chiang’s boundary treatment of the open boundary system into the non-equilibrium Green’s function framework, and then an easy and powerful multiband treatment method is developed to solve the transmission coefficient of Si-based semiconductor quantum structures.

In contrast to the usual wavevector dependent transition coefficients, the velocity-direction dependent transition coefficients of an incident electron are calculated. Through a potential barrier grown on anisotropic semiconductors, the transition coefficients of an incident electron are calculated in all valleys and incident-directions. In the anisotropic semiconductor, the mathematical expressions of the electron wavevector are also derived in the framework of the incident-angle and incident-energy parameters.

The bulk inversion asymmetry (Dresselhaus) terms (i.e., B2, B1, and B′1 terms) of wurtzite materials are determined. The 2 × 2 conduction band, 2 × 2 heavy-hole band, 2 × 2 light-hole band, and 2 × 2 crystal-field split-off hole band matrices of wurtzite semiconductors are developed and decoupled by using a block diagonal technique. Importantly, those 2 × 2 block diagonal matrices incorporate not only the interband coupling effect but also the bulk inversion asymmetry effect. Analytical expressions for the conduction and the valence band spin-splitting parameters and energies of GaN wurtzite materials are formulated by solving the block diagonal matrices. The presence of these terms is shown to include the spin-splitting phenomenon.

This study investigates the optical anisotropy spectrum in the R-plane (i.e., the [ 10 1 ¯ 2 ] -oriented layer plane) of GaN/Al0.2Ga0.8N quantum wells of different widths. The optical matrix elements in the wurtzite quantum wells are calculated using the k ⋅ p finite difference scheme. The calculations show that the valence band mixing effect produces giant in-plane optical anisotropy in [ 10 1 ¯ 2 ] -oriented GaN/Al0.2Ga0.8N quantum wells with a narrow width. The nature of the in-plane optical anisotropy is found to be dependent on the well width. Specifically, it is found that the anisotropy changes from x ′ -polarization to y ′ -polarization as the well width increases.

The optical polarization of GaN/AlGaN wurtzite quantum wells in various orientations is studied using an arbitrarily-oriented [ h k i l ] Hamiltonian potential matrix. The optical matrix elements in the wurtzite quantum wells are calculated using the k ⋅ p finite difference scheme. The results reveal the presence of giant in-plane optical anisotropy (polarized normal to [0001]) in the M-plane (i.e., the ( 10 1 ¯ 0 ) -oriented layer plane) GaN/Al0.2Ga0.8N quantum well, due to the positive crystal-field split energy effect ( Δ CR > 0 ). The present theoretical results are consistent with the photoluminescence measurements presented in the literature [B. Rau, et al., Appl. Phys. Lett. 77 (2000) 3343].

A k⋅p wurtzite Hamiltonian including the bulk (or intracell) inversion asymmetry is developed. Meanwhile, a k⋅p wurtzite optical matrix including this intracell asymmetry is also established.

A conventional 8 ×8 k·p zincblende Hamiltonian is corrected to include the bulk (or intracell) inversion asymmetry. Meanwhile, a conventional 8 ×8 k·p zincblende optical matrix is also corrected to include this intracell asymmetry.

A theoretical method for the calculation of quantum transport in an ellipsoidal valley is presented. This method is developed using a non-equilibrium Green's function framework. Importantly, it is instructive that k z is separated into two parts so that the wrong figure shape of the transmission coefficients does not exist. The L-electron effect on AlAs–GaAs–AlAs double barrier structures oriented in the [001], [111], and [110] growth directions is explored using the proposed method.

The 2×2 conduction band, 4×4 hole band, and 2×2 spin-orbit split-off band matrices of zincblende semiconductors are obtained by using a block diagonal technique. Importantly, the block diagonal matrices incorporate not only the interband coupling effect but also the bulk inversion asymmetry effect. Analytical expressions for the conduction band spin-splitting energies of GaAs zincblende bulk and quantum wells grown on [001]-, [111]-, and [110]-oriented substrates are formulated by solving the block diagonal matrices. The results show that odd-in-k terms exist in both the bulk and the quantum well expressions due to the bulk inversion asymmetry effect. The presence of these terms is shown to induce the spin-splitting phenomenon.