This paper presents a class of power grid analysis and optimization techniques, all of which are based on the algebraic-multigrid (AMG) method. First, a new AMG-based reduction scheme is proposed to improve the efficiency of reducing the problem size for power grid analysis and optimization. Next, with the proposed reduction technique, a fast transient-analysis method is developed and extended to an accurate solver with error control mechanism. After that, the scope of this method is further broadened for handling the analysis of the modified grid. Finally, a fast decap-allocation (DA) scheme based on AMG is suggested. Experimental results show that these techniques not only achieve a significant speedup over reported industrial methods but also enhance the quality of solutions. By using the proposed techniques, transient analysis with 200 time steps on a 1.6-M-node power grid can be completed in less than 5 min; dc analysis on the same circuit can reach an accuracy of in about 141 s. Our DA can process a circuit with up to one million nodes in about 11 min.

Rotary traveling-wave oscillator (RTWO) is a recently pro- posed transmission-line approach for multi-gigahertz rate clock generation. RTWO has the characteristics of both conventional LC tank oscillator and ring oscillator. Thus, it is difficult to be analyzed by a general-purpose method. This paper presents a systematic and efficient method for RTWO modeling and optimization. Equations for frequency, power dissipation, die area, loop gain and phase noise are formulated in posynomial forms. The resulting optimization problem is relaxed to be a Geometric Programming (GP) and can be efficiently solved with a convex optimization solver. A novel scheme to control the rotation direction is also suggested for skew control. Experimental results show that our method can rapidly compute the globally optimal trade-off and reduce the power by up to 85% for a 11.8 GHz RTWO design. Compared to a recently reported low-power methodology, the proposed design scheme can save about 50% of die area and achieve lower power dissipation as well as faster rise/fall time.

Decap (decoupling capacitor) is an effective technique for suppressing power supply noise. Nevertheless, over-usage of decap usually causes excessive power dissipation. Therefore, the total decap area needs to be minimized subject to power supply noise constraints. This is a complicated nonlinear optimization problem that may have as many as millions of variables. We propose an algebraic multigrid (AMG) based method to handle the high complexity. An error compensation scheme is developed to compensate the accuracy loss during the AMG reduction. A charge based back-mapping method and a few other techniques are suggested to further improve the computation efficiency. Our method is flexible to use and can be easily integrated with other existing decap allocation works. When compared to several previous works, the results from our method are usually the closest to the optimum. Our method also runs fast and can solve circuits with up to 1 million nodes in about 11 minutes. In addition, it has better scalability than the previous works.

UMTS system supports a variety of services and applications, providing high data rate access to mobile terminals and cross-domain services to the users. It is divided into two groups: radio access network (RAN) and core network. Simulation results and experimental analysis helps to evaluate the performance, in which the simulation code designed on the top of UMTS networks.

This paper derives the closed form expression for the interference power of narrowband jamming signal on time-hopping ultra-wide bandwidth system with binary pulse position modulation, assuming the jamming signal as a continuous wide sense stationary zero mean random process and the time hopping codes as a pseudorandom sequence. When the bandwidth of the jamming signal is much smaller than the data rate of UWB system, the approximate expression is presented, based on which some design guides for UWB signal parameters selection are given to reduce the interference power when the jamming signal power and the UWB pulse are fixed. Simulations demonstrate all of the analysis.