Home Base Station Research Articles

A Relay-Assisted Handover Technique with Network Coding over Multihop Cellular Networks

A relay-assisted handover technique exploiting network coding for multihop cellular networks is described. In the scheme, each MS (mobile station) in the outer region receives data related to the home cell from the home BS (base station) as well as a coded version of data related to a neighboring BS from a relay node located in the cell boundary via the use of network coding. Thus, MSs can achieve more reliable macro diversity with the assistance of the relay-based handover technique. In a simulation, it is demonstrated that this technique is very effective in maintaining QoS (quality of service) in terms of outage probability over a multi-cell environment

Reverse Link Capacity Analysis over Multi-Cell Environments

This paper presents a numerical analysis of reverse link capacity by obtaining a closed form of ICI (InterCell Interference) over OFDM (Orthogonal Frequency Division Multiplexing)-based broadband wireless networks. In the analysis, shadowing factors are taken into account for determining the home BS (Base Station) of each MS (Mobile Station) over multicell environments. Under the consideration, a more accurate analysis of link capacity can be performed compared to Gilhousen's approximation. In the numerical results, it turns out that the actual interference is lower than Gilhousen's approximation with a decrease of around 20% in the interference.

Viewpoint: One phone to ring them all

Home basestations turn the threat of convergence and unlicensed wireless access into an opportunity for network operators, says the author.

An energy-efficient sensor routing scheme for home automation networks

In the emerging ubiquitous home, sensors are placed everywhere in the house and collect various physical data such as temperature, humidity, and light to provide information to consumer electronics devices. The devices are then automatically activated if necessary. For example, the ventilator works when the air is foul and the heating system performs according to the weather and the existence of people in the house. Because sensors have limited battery power, energy-efficient routing is important. In this paper, we present a new sensor routing scheme that provides energy-efficient data delivery from sensors to the home base station. The proposed scheme divides the home area into sectors and locates a manager node to each sector. The manager node receives collected data from sensors and delivers the data to the base station through the shortest path of the 2-dimensional (x, y) coordinates. Performance results show that the proposed scheme reduces energy consumption significantly compared with conventional sensor routing schemes.

A Distributed Packet Scheduling Scheme with Interference Avoidance for Non Real-Time Applications in CDMA Networks

In this paper, a packet scheduling scheme based on real-time channel conditions and dominant intercell interferer avoidance is proposed, studied and evaluated for reverse links in a time-slotted code division multiple access (CDMA) system. This scheme is implemented by distribution of tags by receivers among transmitters. Each base station issues M(≥1) tags to M mobile users based on the ranked reverse link gains in every slot. M=1 corresponds to spread-spectrum time division multiplexing mode operation and M≥1 corresponds to scheduling multiple simultaneous transmissions as in the traditional CDMA systems. The number of issued tags is a system parameter which depends on the expected traffic, the number of cells and the propagation conditions in the network. In the proposed scheme, users who not only have stronger channel gains to their respective home base stations but also cause relatively lower intercell interference are scheduled for transmissions. Different classes of tags can be issued and various scheduling decision rules can be implemented giving flexibility in interference management. Simulation results in shadow and multipath fading environment are presented to show the performance advantage of the proposed scheme.

Hybrid TDOA/AOA mobile user location for wideband CDMA cellular systems

This paper proposes a mobile user location scheme for wideband code-division multiple-access (CDMA) wireless communication systems. To achieve high location accuracy and low cost of the mobile receiver, the location scheme combines the time difference of arrival (TDOA) measurements from the forward link pilot signals with the angle of arrival (AOA) measurement from the reverse link pilot signal. High chip rates in wideband CDMA systems facilitate accurate TDOA measurements, and a smart antenna used at the home base station (BS) can provide accurate AOA measurement in a macrocell environment. A two-step least square location estimator is developed based on a linear form of the AOA equation in the small error region. Numerical results demonstrate that the proposed hybrid TDOA/AOA location scheme gives a much higher location accuracy than TDOA only location, when the number of base stations is small and/or when the TDOA measurements have a relatively poor accuracy.

Forward-link-power control in CDMA cellular systems

The forward-link (base to mobile) power-control problem in code division multiple access (CDMA) cellular systems is studied. For a better understanding of the problem, a simple analytical model is developed for the neighboring-cell interference experienced by users as a function of distance from their home base station. Using this model, the recently proposed nth-power-of-distance power-control laws are investigated, especially with regard to the possibility of creation of a service hole. The investigation leads to the shape of the optimum radial distance dependent power-control law that will provide uniform service to all the users. >