RE: stds-802-16-mobile: Channel Model
Dear David,
my starting points have been the 29r4 document and the TestiPHY (see
http://wirelessman.org/tga/contrib/C80216a-02_102v2.zip). My goal is: to
modify the TestiPHY sources of the transmitter and to make the receiver
so to match them to 802.16e proposals.
My physical layer is OFDM based (no single carrier).
As channel model, I've implemented the ITU-R M-1225 one (Clarke model)
and I've replaced the SUI channel model (implemented by D.S. Baum in
29r4) with it.
At this moment the received signal is strongly disturbed because of
multipath and the performance (in term of "bit rate") are
reduced of 50%: my goal is implement a (sub-optimal) equalizer so that
performance are reduced of at the most 20-30%.
N.B.: I measure the performance simply evaluating the ratio between the
correct received byte number and the transmitted byte number.
Could you tell me some information that help me, in my
research?
At 19.03 10/11/2003 +0000, you wrote:
Cosimo
There are channel models for
.16, known as SUI: Stanford University Interim models
I think the document is 29r2
from a couple of years ago. This includes a MATLAB
implementation
that is a good starting
point.
Note that .16 isn't desparately
good in terms of mobility, but I'd be interested to hear your views on
that.
The .16e work is concerned with
handover, but I don't think the expectation is that SS will move
desparately quickly: others may disagree.
There is also plenty of work on
channel models currently in 802.20: it would be worth checking that
out.
Equalisers are clearly a
significant element in the performance of an 802.16 system, but as this
is a receiver function, there is (deliberately) no information in the
standard on how to implement one, and this knowledge tends to remain
company confidential.
Note, however, in the OFDM
physical layers, the separate carriers are independent so long as the
multipath does not exceed the Guard Interval.
If you were interested in
single carrier PHY, then there are some notes about equivalence of the
required equalisers with the transformations needed in OFDM.
Regards
David Castelow
The comments are personal and
do not represent the views of Airspan Communications.
- -----Original Message-----
- From: Cosimo Palazzo
[mailto:cosimo.palazzo@unile.it]
- Sent: 10 November 2003 16:39
- To: stds-802-16-mobile@ieee.org
- Subject: stds-802-16-mobile: Channel Model
- Dear members,
- I'm an undergraduate student of the University of Lecce (Italy): I'm
doing a research about the TCP performance in the wireless
environment.
- I'm studying a network composed by more wireless networks (little
range networks like 802.11e, and big range networks like 802.16e) that
are connected together.
- In this moment I'm trying a channel model for each wireless section
of my scenario of study. My goal is to formulate a Markovian channel
model (or similar) to simulate the activity of 802.16e in urban
environment; the BS is fixed but the SSs are mobile (vehicular velocity,
20-80 Km/h).
- In this moment I'm making a Matlab implementation of the physical
layer for 802.16e. My problem is the choice of the equalizer block at
the receiver: could you tell me some information about the state-of-art
of this choice? Which equalizer will be proposed for 802.16e draft?
- Could you tell me where I can find Matlab sources (or similar) for
this equalizer?
- Thanks in advance.
- Cosimo Palazzo (Università degli Studi di Lecce - Italy)