summaryrefslogtreecommitdiffstats
path: root/vorlagen/thesis/src/kapitel_x.tex
diff options
context:
space:
mode:
Diffstat (limited to 'vorlagen/thesis/src/kapitel_x.tex')
-rw-r--r--vorlagen/thesis/src/kapitel_x.tex21
1 files changed, 17 insertions, 4 deletions
diff --git a/vorlagen/thesis/src/kapitel_x.tex b/vorlagen/thesis/src/kapitel_x.tex
index 91b5cb0..6883955 100644
--- a/vorlagen/thesis/src/kapitel_x.tex
+++ b/vorlagen/thesis/src/kapitel_x.tex
@@ -2719,6 +2719,11 @@ data generator as open source to be wider extended or ported to another
programming language, it was required to be written in a programming language
understandale by wider audience. It was sound to write the RRLP assistance
data generator in C++ because OpenBSC was written in C and OpenBTS in C++.
+The main tasks here can be split up down to: verify the existance and age of
+assistance data download of the assistance data, conversion of the data,
+verification of their correctness, construction of RRLP packets according to
+the ASN.1 standard, conversion of it to PER and at last saving in the
+hexadecimal form in a text file.
In the almanac
and ephemeris files, downloaded from NASA and Trimble, assistance data were stored
@@ -2744,7 +2749,7 @@ to be in the specified range as in the standard. Afterwards the converted
and verified assistance data were combined into binary series of data
according to the RRLP standard as described in chapter \ref{rrlpChapt}.
If the assistance data packet size in binary format was not divisible by eight
-then additional padding zeros are added until this condition was satisfied.
+then additional padding zeros were added until this condition was satisfied.
Better comprehension of the RRLP assistance data generator can be gained
by looking at the flowchart in figure \ref{img:RRLPAlgFlowchart}.
@@ -2766,9 +2771,16 @@ but with two hours older ephemeris data. If the AGPS receiver in the MS uses
the ephemeris data from that particular satellite then the distance estimation
is affected and may contain errors! This problem is well known and confirmed
by different studies \citep{Stanford-Ephem-Errors} \citep{NASA-Ephem-Errors}.
-A solution to this problem is proposed in the future work section. Once the
-assistance data have been generated and saved in a text file they can be used
-by OpenBSC to be transmitted to the MS.
+A solution to this problem is proposed in the future work section \ref{sec:futWork}. Once the
+assistance data have been generated, converted to hexadecimal notation and
+saved to a text file they can be used by OpenBSC to be transmitted to the MS.
+The decision to save the data to a text file, instead of storing to the database,
+was made because OpenBSC is a real-time system. If the database does not
+respond OpenBSC' real-time functionality might be lost and the system will
+malfunction. Since the text file is small and accessed only when an RRLP
+request is queued, it is faster than initializing the database driver,
+opening a socket connection to the database, making request queries to the
+database, obtaining the result and closing the socket connection.
\section{Creating data channel in OpenBSC}
@@ -3292,6 +3304,7 @@ These errors were not continual but appeared occasionally and these errors
were inside of the assistance data provided by NASA.
\section{Future work}
+\label{sec:futWork}
The system could be extended with a GPS device that delivers raw GPS data
instead of using the data provided by NASA and Trimble. Obtained data by the GPS
could be compared to the data provided by NASA or other GPS observation stations