Towards a 4G IP-based Wireless System Proposal.
Chalmers U. of Technology
Chalmers U. of Technology and
Radiovetenskap och Kommunikation RVK 02,
Stockholm, June 2002.
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.
A packet switched wireless cellular system
with wide area coverage, high throughput
and high spectral efficiency is proposed.
Smart antennas at both base stations
and mobiles improve the antenna gain and
improve the signal to interference ratio.
The small-scale fading is predicted
in both time and frequency
and a slotted OFDM radio interface is used,
in which time-frequency bins are allocated
adaptively to different mobile users, based on
their predicted channel quality. This enables
among sectors and users as well as fast
adaptive modulation and power control.
We here estimate the spectral efficiency
of the suggested downlink.
The resulting channel capacity
grows with the number of
simultaneous users and with
the number of antenna elements in terminals.
A high efficiency, around 4 bits/s/Hz,
is attained already for
moderate numbers of users and
An outline is given of research pursued within
the PCC Wireless IP Project
to improve and investigate this type of system.
The uplink of this
system proposal, presented at WWRF March 2002, Phoenix, Arizona.
Licenciate Thesis by Nilo C. Ericsson
on predictive scheduling combined with adaptive modulation.
Licenciate Thesis by Sorour Falahati, Feb. 2000.
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.
Some other presentations by Wireless IP at RVK02:
An overview of the Wireless IP Project
Improved Channel Power Prediction,
by using unbiased predictors and advanced regressor noise reduction.
Optimizing adaptive modulation,
by taking the power prediction error into account.
Simulating TCP/IP traffic
over wireless links in real time.
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