Toward 4G IP-based Wireless Systems:
A Proposal for the Uplink.

Tony Ottosson, Chalmers U. of Technology
Anders Ahlén, Uppsala University
Anna Brunström, Karlstad University
Mikael Sternad, Uppsala University and
Arne Svensson, Chalmers U. of Technology.

Wireless World Research Forum Workshop, Phoenix, Arizona, March 2002 and London, June 2002.

Outline:

The Wireless IP project within the PCC program studies problems that are crucial in the evolution of UMTS towards high data rates, as well as in future 4G technologies aimed at rapidly mobile terminals. The goal is to attain higher througputs for packet data in particular in downlinks, without bandwidth expansion and while providing acceptable quality of service for various classes of traffic.

Abstract:

A packet switched wireless cellular system with wide area coverage and high throughput is proposed. The system is designed to be cost effective and to provide high spectral efficiency.

It makes use of a combination of tools and concepts: Smart antennas both at base stations and mobiles, provide antenna gain and improve the signal to interference ratio. The fast fading is predicted in both time and frequency and a slotted OFDM radio interface is used, in which time-frequency slots are allocated adaptively to different mobile users, based on their predicted channel quality. This enables efficient scheduling among sectors and users as well as fast adaptive modulation and power control.

We here outline the uplink of the radio interface. Calculations based on simplifying assumptions illustrate how the channel capacity grows with the number of simultaneous users and the number of antenna elements. A~high capacity can be attained already for moderate numbers of users and base station/terminal antennas.

Related publications:

The downlink of this system proposal, presented at WWRF Dec 2001, Paris.

Licenciate Thesis by Nilo C. Ericsson (June 2001), on predictive scheduling combined with adaptive modulation.

Licenciate Thesis by Sorour Falahati, Feb. 2000.

VTC01spring-paper on channel prediction over 1-10 ms horizons.

Scheduling and adaptive transmission for the downlink 4G systems similar to the one discussed here (FTC 2001, Beijing).

An overview of the Wireless IP Project, NRS 01.

Source:

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