| Author | Chinnasri Suriyadetsakul |
| Call Number | AIT Thesis no.TC-99-2 |
| Subject(s) | Wireless communication systems
|
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering. School of Advanced Technologies |
| Publisher | Asian Institute of Technology |
| Abstract | This thesis work studies the handover performance of variable bit rate (VBR) sources
in the wireless ATM network that has constant bit rate (CBR) sources generating the
background traffic. In addition to the connection level performance, the cell level
performance, including the cell loss probability, cell delay and bandwidth utilization, is taken
into account.
In order to study this cell level performance, the aggregate CBR and VBR cell
streams are generated based on the numbers of ongoing CBR and VBR calls in the system
and their traffic source parameters, while the discrete-state, continuous-time Markov process
is exploited as the VBR source model. At the base station, statistical multiplexing is utilized
to multiplex the ATM cell streams. The measurement-based prioritization scheme is used as
the handover queuing method that gives priority to handover calls over new calls. To provide
the guaranteed cell level QoS to all admitted calls, the diffusion based statistical call
admission control (CAC) and the quality of service (QoS) cell discarding scheme are
employed.
Under the assumption that VBR traffic demand is considerably large, the offered
traffic from VBR calls is assumed to be 50 % of that from CBR calls. The simulation results
show that VBR traffic characteristics have considerable effect on the connection level and
cell level performances. Under a high offered load condition, a high VBR call burstiness
causes VBR calls to face much higher handover call and new call blocking probabilities,
while CBR call blocking probabilities are still low. In cell level, the increase of offered load
causes the cell loss probabilities and mean cell delays of both services to increase. When the
offered load is large, high VBR call burstiness causes the served ATM cells to have shorter
mean cell delay. Besides, considering the aspect of resource utilization, over the range of
high offered load this high VBR call burstiness results the bandwidth utilization to be
inefficient. |
| Year | 1999 |
| Type | Thesis |
| School | School of Advanced Technologies |
| Department | Department of Information and Communications Technologies (DICT) |
| Academic Program/FoS | Telecommunications (TC) |
| Chairperson(s) | Erke, Tapio; |
| Examination Committee(s) | Ahmed, Kazi M. ;Rajatheva, R.M.A.P.; |
| Scholarship Donor(s) | Royal Netherlands Government ; |
| Degree | Thesis (M.Eng.) - Asian Institute of Technology, 1999 |