Downlink radio resource management to enhance QoS of multimedia services in lte networks
Long Term Evolution (LTE) has become the most dominant Fourth Generation (4G) mobile broadband network. The Radio Access Network (RAN) in LTE is designed to deliver a high trend of Quality of Service (QoS) over diverse user applications and several network scenarios. Therein, the functions of Rad...
Saved in:
| Main Author: | |
|---|---|
| Format: | Thesis |
| Language: | English |
| Published: |
2018
|
| Subjects: | |
| Online Access: | http://psasir.upm.edu.my/id/eprint/76983/1/FSKTM%202018%2070%20-%20IR.pdf |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| Summary: | Long Term Evolution (LTE) has become the most dominant Fourth Generation
(4G) mobile broadband network. The Radio Access Network (RAN) in LTE is
designed to deliver a high trend of Quality of Service (QoS) over diverse user
applications and several network scenarios. Therein, the functions of Radio
Resource Management (RRM) features which span over the LTE protocol stack
should be carefully developed to address related challenges, such as bandwidth
utilization, resources scheduling, and physical channel’s power allocation. In
upper level of downlink Medium Access Control (MAC) layer, the bandwidth
distribution function is resided to manage the channel bandwidth over the
offered user traffic to guarantee fair service. The performance of this function
presents weaknesses when schemes such as Packet Prediction Mechanism
(PPM) are adopted, hence the bandwidth is distributed in a linear and greedy
fashion. Furthermore, flows scheduling with on-time transmissions is essential
in Real-Time (RT) applications. PPM seems to guarantee a stable low delay for
kinds of burst applications, other RT traffic are severely compromised though
due to the aggressive data dropping procedures in high network overload
states. From another aspect, recent QoS profiles count for energy-efficient
transmissions as a core dimension. However, this aim still seeks a margin of
enhancements with respect to the relevant power allocation schemes as seen in
Piro and Lee schemes to focus on controlling the transmission power beside the
system capacity maximization in order to maintain a long-term energy-efficient
transmissions.
This study figures out managing radio resources over different users for a
particular purpose. The first proposal considers the issue of downlink channel
resource distribution among different multimedia applications which lead to unfair service. Therefore, a "Frame-based Game Theory (FGT)" bandwidth distribution
scheme is proposed for the MAC layer in the downlink LTE channel.
In FGT, bandwidth is shared based on the data rate requirements of each traffic
flow over the entire LTE frame. Simulation results reveal that FGT enhances
the service fairness up to 25% with respect to the existing reference scheme and
maintain a high data rate for different users.
The second proposal considers the issue of flows scheduling for different RT
flows. Therefore, Delay-based and QoS Aware Scheduling (DQAS) scheme
is introduced to assign channel resources to delay sensitive flows based on
QoS-derived rules for different flow types in a way to guarantee low latency
and maintain a good data rate. Simulation results show that the efficient delay
control in DQAS allows RT flows transmission with 55% minimum delay time
compared to existing schemes and guarantees a reasonable throughput level for
non-real time flows.
Finally, the issue of surplus power allocation at the base station which degrades
the system energy efficiency is discussed thoroughly. Accordingly,
Link-adaptive Power Control and Allocation (LaPCA) scheme is proposed
to tune the allowable power for the base station and adhere distributes this
determined power among the utilized subchannels to transmit users’ data. The
performance evaluation results indicate that LaPCA guarantees a high trend of
energy-efficiency at the base station up to 23% with respect to existing works
and keeps an outperforming level of network downlink transmissions.
The findings of this study conceive several significant enhancements that are
realized by the proposed RRM schemes. These enhancements include: a guaranteed
fair bandwidth sharing among multi-traffic transmitted in unified LTE
channel by introducing FGT scheme; stable and low delay for RT flows by introducing
DQAS scheme; and finally, energy-efficient downlink transmissions
with maximized system capacity by introducing LaPCA. Applying these proposed
RRM-schemes in the current protocol stack of LTE radio access network
persistently supports a high QoS level for communicating multimedia services
in urban-like scenarios. Whereby, network utility and energy-efficient transmissions
are significantly returned. This indeed allows more agility for network
operators to define their QoS profiles which consequently maintain a long-term
network service continuity within the kinds of highly dense environments. |
|---|