The Juridical Status of Privileged Combatants Under the Geneva Protocol of 1977 Concerning International Conflicts

Centralized control and coordination of the connections in a wireless network is not possible in practice. To keep the delay from measure-ment instants to actuating the decisions, distributed control is required. This paper focuses on the uplink (from mobiles to base stations) and dis-cusses distributing the decision of when and when not to transmit data (distributed scheduling) to the mobiles. The scheme, uplink transmission timing, utilizes mobile transmitter power control feedback from the base station receiver to determine whether the channel is favorable or not compared to the average channel condition. Thereby, the battery consumption and disturbing power to other connections are reduced. The algorithm can be described as a feedback control system. Some transient behaviors are analyzed using systems theory, and supported by wireless network simulations of a system with a WCDMA (Wideband Code Division Multiple Access) radio interface as in most 3G systems

The Due-on-Sale Controversy: Beneficial Effects of the Garn-St. Germain Depository Institution Act of 1982

Radio resource management (RRM) in cellular radio system is an example of automatic control. The system performance may be increased by introducing decentralization, shorter delays and increased adaptation to local demands. However, it is hard to guarantee system stability without being, too conservative while using decentralized resource management. In this paper, two algorithms that both guarantee system stability and use local resource control are proposed for the uplink (mobile to base station). While one of the algorithms uses only local decisions, the other uses a central node to coordinate resources among different local nodes. In the chosen design approach, a feasible solution to the optimization problems corresponds to a stable system. Therefore, the algorithms will never assign resources that lead to an unstable system. Simulations indicate that the proposed algorithms also provide high capacity at any given uplink load level

Incentives vs. Nonpartisanship: The Prosecutorial Dilemma in an Adversary System

The limiting factor in the uplink of all CDMA cellular systems is the relation between uplink noise rise and intended coverage. In link budgets, noise rise is usually simply handled as a constant contribution to the background noise in logarithmic scale, often referred to as interference margin. In practice, however, it is not constant. We model the uplink noise rise as a lognormal distribution, and investigate the impact to link budgets. Simulations and numerical calculations show that the uplink noise rise variance does not critically affect the uplink capacity and coverage. System feasibility and its relation to the uplink load is also discussed. It is shown that approximative load expressions provides an upper bound on the uplink load and therefore they can be used to imply system feasibility. Furthermore, the uplink load expressions provide accurate approximations of the load given that the load is within the practical limits given by the link budgets

Uplink Load in CDMA Cellular Radio Systems

The uplink of code division multiple access (CDMA) cellular radio systems is often interference limited. The interference originates from many users whose transmission powers are not observable for the system. This thesis introduces uplink load and applies means of explicitly considering the users’ radio environment when approximating and controlling the load. A desirable property of all cellular radio systems is uplink feasibility, i.e., existence of finite user transmission powers to support the allocated services. Uplink load can be considered as a measure of how far from infeasibility the system is. The performed characterization of uplink load lead to two concrete definitions related to the amount of received and transmitted power, respectively. An important part of the total load is the intercell load which is caused by users connected to neighboring base stations. If not carefully handled, the intercell load can jeopardize uplink feasibility. Conversely, knowledge of a lower intercell load can be used to increase the resource assignments. A common denominator in all the work in this thesis is that the intercell load is explicitly considered

Admission Control in Cellular Radio Systems Based on Relative Load Estimates

When operating a cellular radio system nearly at full capacity, admitting yet another user may jeopardize the stability of the system as well as the performance of the individual users. Therefore, proper admission control is crucial. The core idea in this work is to predict the relative load of the system, given that a user is admitted. Then, the user will be admitted if the predicted load in the specific cell, and in its neighbors, is below some threshold. This provide an interesting alternative to algorithms based on hard capacity, which might be utilizing the resources inefficiently in order to be robust. The proposed uplink admission control algorithm utilizes measurements readily available in the system. Simulations indicate performance improvements. Furthermore, multi-services are naturally handled, and availability of high data-rate services are automatically limited with respect to coverage, compared to services of lower data-rate

Uplink Load Estimates in WCDMA with Different Availability of Measurements

In the uplink of a WCDMA system, a natural choice of resource management control quantity is the uplink noise rise, i.e., total received power over noise power. Unfortunately this quantity is hard to measure. In this paper, we propose and evaluate a number of noise rise estimates which all rely on path gain measurements. These measurements can be made available either periodically or event-driven as described in 3GPP (Release 99). Simulations show that event-driven measurements yield comparable performance to periodic measurements, but with much fewer measurement reports. Despite severely limited path gain knowledge due to that some users report to another RNC, we still manage to estimate the uplink noise rise reasonably well

Uplink Load Estimation in WCDMA

All cellular radio systems depend on well performing radio resource management algorithms to efficiently utilize available resources. These algorithms make their decisions based on some sort of resource quantity. In the uplink of a WCDMA system, the total received power at the base stations is a natural choice of such a quantity. Unfortunately this quantity cannot be measured with enough accuracy to be used by resource management algorithms. One way of getting around this problem is to estimate a closely related quantity, namely the uplink noise rise. In this paper, we propose and evaluate four different methods to estimate the noise rise. The estimates are insensitive to users bit rate and use data readily available in the system. The best performing method estimates, on average, the uplink noise rise with an error of less than 1 dB for practical load scenarios

Adaptive Filtering Applied to an Uplink Load Estimate in WCDMA

In the uplink of a WCDMA system, a natural choice of resource quantity is the uplink noise rise, i.e., total received power over noise power. Unfortunately this quantity is hard to measure and estimates are often noisy. This paper focuses on relative load which is closely related to the noise rise. Model-based signal processing with change detection techniques is herein used to suppress noise and minor oscillations while being alert on fast load changes. The time varying model identified in the process can also be used for prediction of future values, something which resource management algorithms can benefit from

Uplink Load Estimation in WCDMA

All cellular radio systems depend on well performing radio resource management algorithms to efficiently utilize available resources. These algorithms make their decisions based on some sort of resource quantity. In the uplink of a WCDMA system, the total received power at the base stations is a natural choice of such a quantity. Unfortunately this quantity cannot be measured with enough accuracy to be used by resource management algorithms. One way of getting around this problem is to estimate a closely related quantity, namely the uplink noise rise. In this paper, we propose and evaluate four different methods to estimate the noise rise. The estimates are insensitive to users bit rate and use data readily available in the system. The best performing method estimates, on average, the uplink noise rise with an error of less than 1 dB for practical load scenarios