Abstract:
This paper presents the results of measured TCP performance in the LA process during
the deployment of GPRS CS1 and CS2 coding schemes and after the activation of two
more coding schemes, CS3 and CS4. The measurements are carried out in one of the
commercially deployed live GPRS networks in Malaysia, using end-to-end FTP file
transfer application for the assessment. Tracing at the GPRS air interface is done
simultaneously. The results show that TCP works well in the LA process and can adapt
to the frequent switching between the coding schemes without any problem. The
average throughput is increased by 23% for urban areas owing to the activation of
higher coding schemes and aided by TCP tuning. It is also shown that throughput is
limited by the current coding scheme used and good channel condition is necessary to
optimize TCP performance.