CDMA

Many processes can be represented in a simple form as infinite-order linear series. In such cases, an approximate model is often derived as a truncation of the infinite-order process, for estimation on the finite sample. The literature contains a number of asymptotic distributional results for least squares estimation of such finite truncations, but for quantile estimation, results are not available at a level of generality that accommodates time series models used as finite approximations to processes of potentially unbounded order. Here we establish consistency and asymptotic normality for conditional quantile estimation of truncations of such infinite-order linear models, with the truncation order increasing in sample size. We focus on estimation of the model at a given quantile. The proofs use the generalized functions approach and allow for a wide range of time series models as well as other forms of regression model. The results are illustrated with both analytical and simulation examples.

Abstrucl-We consider the problem of scheduling multiple users sharing a time-varying wireless channel. (As an example, this is a model of scheduling in 3G wirelw technologies, such as CDMAZUOO 3GlxEV-DO downlink scheduling.) We introduce an algorithm which seeks to optimize a concave utility function E, H,(R) of the user throughputs R,, subject to certain lower and upper tlwoughpui bounds: Rrzn 5 R, 5

The development of technological capability (TC) is critical for manufacturing firms in high-tech industries. Stages of development of industrial technology in a developing country: a model. Research Policy 9, 254-277] model of acquisition, assimilation, and improvement is widely accepted to explain TC development in developing economies. However, some R&D practices we observed in Chinese manufacturing companies appear to be in disagreement with Kim's model. Based on four in-depth cases studies set in China's mobile phone industry, we hypothesize (a) a complementary stage in Kim's model, and (b) those stages can be traversed concurrently. r

Next-generation cellular networks are expected to enable the coexistence of macro and small cells, and to support differentiated quality-of-service (QoS) of mobile applications. Under such conditions in the cell, due to a wide range of supported services and high dependencies on efficient vertical and horizontal handovers, appropriate management of handover traffic is very crucial. Furthermore, new emerging technologies, such as cloud radio access networks (C-RAN) and self-organizing networks (SON), provide good implementation and deployment opportunities for novel functions and services. We design a multi-threshold teletraffic model for heterogeneous code division multiple access (CDMA) networks that enable QoS differentiation of handover traffic when elastic and adaptive services are present. Facilitated by this model, it is possible to calculate important performance metrics for handover and new calls, such as call blocking probabilities, throughput, and radio resource utilization. This can be achieved by modelling the cellular CDMA system as a continuous-time Markov chain. After that, the determination of state probabilities in the cellular system can be performed via a recursive and efficient formula. We present the applicability framework for our proposed approach, that takes into account advances in C-RAN and SON technologies. We also evaluate the accuracy of our model using simulations and find it very satisfactory. Furthermore, experiments on commodity hardware show algorithm running times in the order of few hundreds of milliseconds, which makes it highly applicable for accurate cellular network dimensioning and radio resource management. Keywords quality of service · handover · cdma · cloud radio access network

In this paper we examine the aggregate throughput of the uplink of a circuit switched CDMA data transmission system using a combination of theoretical and simulation techniques. The theoretical analysis determines the transmitter power levels and the number of active terminals that jointly maximize the throughput via standard optimization methods. We find that the terminal with the lowest path gain should transmit at maximum power and that all other terminals should aim for a common received power level that is higher than the received power from the terminal with lowest path gain. In addition we show that the system should admit the number of terminals that results in a target signal-to-interference-plus-noise ratio that depends on the processing gain and the noise power. A numerical example suggests that power control designed to achieve equal received power for all terminals results in aggregate throughput nearly as high as that obtained with optimum power control. This finding greatly simplifies the engineering problem from a network manager’s viewpoint.