Femtocells, despite their name, pose a potentially large disruption to the carefully planned cellular networks that now connect a majority of the planet's citizens to the Internet and with each other. Femtocells - which by the end of 2010 already outnumbered traditional base stations and at the time of publication are being deployed at a rate of about five million a year - both enhance and interfere with this network in ways that are not yet well understood. Will femtocells be crucial for offloading data and video from the creaking traditional network? Or will femtocells prove more trouble than they are worth, undermining decades of careful base station deployment with unpredictable interference while delivering only limited gains? Or possibly neither: are femtocells just a "flash in the pan"; an exciting but short-lived stage of network evolution that will be rendered obsolete by improved WiFi offloading, new backhaul regulations and/or pricing, or other unforeseen technological developments? This tutorial article overviews the history of femtocells, demystifies their key aspects, and provides a preview of the next few years, which the authors believe will see a rapid acceleration towards small cell technology. In the course of the article, we also position and introduce the articles that headline this special issue.

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Femtocells: Past, Present, and Future

An organic light emitting display apparatus that has high (or improved) contrast and/or impact resistance. The organic light emitting display apparatus includes: a substrate; an organic light emitting device on the substrate to display an image; a sealing member on the organic light emitting device; a semitransparent film on a surface of the sealing member facing away from the organic light emitting device to transmit a portion of external light and to reflect another portion of the external light; a passivation film on the semitransparent film to protect the semitransparent film; and a transmissive black layer between the sealing member and the organic light emitting device to increase contrast, wherein the semitransparent film has a refractive index greater than that of the passivation film.

Organic light emitting display apparatus

A wireless telecommunication system comprises base stations for communicating with terminal devices. One or more base stations support a power boost operating mode in which a base station's available transmission power is concentrated in a subset of its available transmission resources to provide enhanced transmission powers as compared to transmission powers on these transmission resources when the base station is not operating in the power boost mode. A base station establishes an extent to which one or more base stations in the wireless telecommunications system support the power boost operating mode conveys an indication of this to a terminal device. The terminal device receives the indication and uses the corresponding information to control its acquisition of a base station of the wireless telecommunication system, for example by taking account of which base stations support power boosting and/or when power boosting is supported during a cell attach procedure.

Telecommunications apparatus and methods

Inter-vehicle communication (IVC) systems (i.e., systems not relying on roadside infrastructure) have the potential to radically improve the safety, efficiency, and comfort of everyday road travel. Their main advantage is that they bypass the need for expensive infrastructure; their major drawback is the comparatively complex networking protocols and the need for significant penetration before their applications can become effective. In this article we present several major classes of applications and the types of services they require from an underlying network. We then proceed to analyze existing networking protocols in a bottom-up fashion, from the physical to the transport layers, as well as security aspects related to IVC systems. We conclude the article by presenting several projects related to IVC as well as a review of common performance evaluation techniques for IVC systems.

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Inter-vehicle communication systems: a survey

The object is achieved by providing a base station apparatus for performing time and frequency scheduling in uplink packet access with: an interference amount measurement part configured to measure an uplink interference amount for each interference amount measurement unit which comprises a predetermined period and a predetermined number of frequency blocks; an interference amount determination part configured to determine whether the uplink interference amount satisfies a predetermined condition; and an overload indicator reporting part configured to report an overload indicator to a neighboring cell when the predetermined condition is satisfied.

Base station apparatus and communication control method

Femtocells are low-power base stations operating in licensed spectrum, which are typically installed indoors in a house, small office, or home office by end users to provide exclusive or preferential access to a designated group of users as configured by the femtocell subscriber and/or the access provider. Femtocells have gained a lot of attention recently due to their advantages in terms of infrastructure cost saving and improved user experience in indoor environments. Several standards bodies, such as 3GPP, WiMAX Forum, and IEEE 802.16, have started to develop standard solutions to enable and optimize femtocells operation. However, there are some technical challenges to the success of femtocell technologies that need to be overcome before they can be deployed on large scales. This article presents an overview of WiMAX femtocell requirements, deployment models, and solutions in the near and long terms.

WiMAX femtocell: requirements, challenges, and solutions

The present invention relates to a method for verifying a charging state of a wireless power receiving apparatus in the wireless power transmitting apparatus, and more particularly, to an apparatus and a method for efficiently performing and controlling wireless power transmission. To this end, the present invention provides a wireless power transmitting method, wherein a standby state of determining whether at least one wireless power receiving apparatus is positioned within a wireless charge range of the wireless power transmitting apparatus and a power transfer state of transmitting power to the corresponding wireless power receiving apparatus when at least one wireless power receiving apparatus is detected in the standby state are provided, and the standby state includes a first standby state of periodically transmitting a weak detector signal and a strong detector signal and a second standby state in which at least one of a transmission period of the weak detector signal and a transmission period of the strong detector signal is different from that of the first standby state, the method including: determining any one state of the first standby state and the second standby state of the wireless power transmitting apparatus; and transmitting the weak detector signal and the strong detector signal based on the determined standby state, wherein the transmission period of the weak detector signal in the second standby state is longer than the transmission period of the weak detector signal in the first standby state.

Wireless power transmission apparatus and wireless power transmission method

A method and an apparatus of transmitting information in a wireless communication system are provided. The method includes transmitting information based on a first resource index through a first antenna and transmitting the information based on a second resource index through a second antenna.

Method and apparatus of transmitting information in wireless communication system

A method of transmitting control signals in a wireless communication system includes multiplexing a first control signal with a second control signal in a slot, the slot comprising a plurality of orthogonal frequency division multiplexing (OFDM) symbols in time domain, the plurality of OFDM symbols being divided into a plurality of data OFDM symbols and a plurality of reference signal (RS) OFDM symbols, wherein the first control signal is mapped to the plurality of data OFDM symbols after the first control signal is spread by a base sequence in the frequency domain, the RS is mapped to the plurality of RS OFDM symbols, the second control signal is mapped to at least one of the plurality of RS OFDM symbols, and transmitting the first control signal and the second control signal in the slot.

Method of transmitting control signals in wireless communication system

A method and device for transmitting uplink control signals in a wireless communication system, the method including: reserving a preassigned scheduling request (SR) physical uplink control channel (PUCCH) resource used for transmission of a SR; determining a frequency domain sequence and an orthogonal sequence based on the preassigned SR PUCCH resource; spreading an ACK/NACK for Hybrid Automatic Repeat Request (HARQ) with the frequency domain sequence and the orthogonal sequence to generate a mapped sequence; and transmitting the mapped sequence.

Jin Sam Kwak

Papers

WiMAX femtocell: requirements, challenges, and solutions

Wireless power transmission apparatus and wireless power transmission method

Method and apparatus of transmitting information in wireless communication system

Method of transmitting control signals in wireless communication system

Method of transmitting uplink control signals in wireless communication system