In this chapter, the framework model represented pertains to analyze the performance of UE’s HO algorithm in LTE systems. A HY-HO technique is proposed to cover the short com- ings of the existing approaches. The HY-HO scheme is based on the combination of SHO and
122 Chapter5. Intra-MME/S-GW Handover inVirtualized3GPP-LTE Systems 0 5 10 15 20 25 30 0 20 40 60 80 100 120
Average packets delay for mobility speeds 150 Km/hr and 350 Km/hr
Time
Average packet delay (ms)
EF HHO 150 Km/hr non−EF HHO 150 Km/hr EF HY−HO 150 Km/hr non−EF HY−HO 150 Km/hr EF Vir. HY−HO 150 Km/hr non−EF Vir. HY−HO 150 Km/hr EF HHO 350 Km/hr
non−EF HHO 350 Km/hr EF HY−HO 350 Km/hr non−EF HY−HO 350 Km/hr EF Vir. HY−HO 350 Km/hr non−EF Vir. HY−HO 350 Km/hr UE performs HO
with speed 350 Km/hr UE performs HOwith speed 150 Km/hr
Figure 5.14: The average packets delay (EF and non-EF traffic) for mobility speeds 150 and 350 Km/hr versus time.
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
101 102
Average packets delay for mobility speed 150 Km/hr
Distance
Average packet delay (ms)
EF HHO EF HY−HO EF Vir. HY−HO
Figure 5.15: The average packets delay (high dense EF traffic) for mobility speed 150 Km/hr versus distance.
5.10. Conclusion 123
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
101 102
Average packets delay for mobility speed 350 Km/hr
Distance
Average packet delay (ms)
EF HHO EF HY−HO EF Vir. HY−HO
Figure 5.16: The average packets delay (high dense EF traffic) for mobility speed 350 Km/hr versus distance.
0 5 10 15 20 25 30
101 102
Average packets delay for mobility speeds 150 Km/hr and 350 Km/hr
Time
Average packet delay (ms)
EF HHO 150 Km/hr EF HY−HO 150 Km/hr EF Vir. HY−HO 150 Km/hr EF HHO 350 Km/hr EF HY−HO 350 Km/hr EF Vir. HY−HO 350 Km/hr
Figure 5.17: The average packets delay (high dense EF traffic) for mobility speeds 150 and 350 Km/hr versus time.
124 Chapter5. Intra-MME/S-GW Handover inVirtualized3GPP-LTE Systems
HHO. The combination was able to enhance the system performance in term of latency, inter- ruption time and reliability during handover especially at cell boundary.
Also, the combination reduces the transmission overhead on the serving cell, which bal- ances the traffic load within the system cells in LTE. I also evaluated the average packets delays for cases of SS and DS schemes, with the goal to close the growing gap between the capacities of backbone networks.
According to the simulation results, HY-HO virtualized DS scheme is capable of achiev- ing great improvements with respect to delay when compared to the non-sharing application. This improvement allows SPs to customize their efforts, schedulers, and control the sharing of multi-SP resources between them.
Overall, the results confirm that the HY-HO framework yields notable improvements in av- erage packet delay, without degrading QoS support for EF, AF, and BE services. Nonetheless, the performances of AF and BE as non-EF services are yet to be further improved, and QoS to be better delivered.
Chapter 6
Thesis Summary and Future Work
As time goes on, the need for enhancing QoSs’ parameters in order to reach a future tech- nology becomes more and more paramount. Interestingly enough, while the penetration rate for mobile users and breadth of device features continues to increase, the need for more reaearch improvement in wireless communication networks is still of importance.
6.1
Thesis Summary
In this thesis designs are proposed for both scheduling and resource allocation methods that offer reduced complexity in multi-stream (multi-user), virtualized scenarios in both DL and UL systems.
In Chapter 3, I examined a novel design for a virtualized resources’ sharing technique. This novel approach can be used to efficiently schedule traffic streams with differing QoS param- eters without needing to result to full scale optimization techniques while still guaranteeing throughput and average delay constraints.
Wherein, SPs using different scheduling algorithms are sharing their physical radio RBs in one eNB in a virtualized scheme as a promising solution for reducing operational and capital expenditures. The proposed method makes use to schedule traffic with various delay and pri- ority requirements.
126 Chapter6. ThesisSummary andFutureWork
However, next in Chapters 4 and 5 this dynamic virtualization was considered. First, the main contributions in Chapter 4 resulted in a detailed study of modeling an optimized solu- tion for the simulated sharing scheme methodology used in Chapter 3. Wherein, an optimized efficient power scheduling was proposed for a dynamic policy framework, which meets ex- clusive and contiguous allocation, maximum transmission power, and rate constraints restric- tions while minimizing the average applied transmission power for a time-invariant channel to achieve green communication.
This dynamic virtualized scheme was used in Chapter 5 to design an extended schedul- ing scheme that exploited this information about the underlying channel statistics. The main contribution of this Chapter 5 was an extension of the work in Chapter 3. Wherein, the per- formance of UEs random-way mobility model and HO algorithms for high-mobility users was analyzed in a virtualized LTE systems. A HY-HO technique is proposed to address the short- comings of the existing approaches and the challenges caused by the demand for high data rates. The results confirm that the HY-HO framework yields notable improvements in average packet delay, without degrading QoS.
Overall, one of the primary arguments made in this thesis is the large complexity associated with heterogenous scheduling techniques, particularly when attempting to minimize energy ex- pended in the mobile radio. While in this thesis, methods of complexity reduction in scheduling were shown while attempting to minimize energy expenditure, it is important to note that this research area is still wide open and that there is no single solution to this complexity problems. This is particularly true as the constraints imposed by practical systems vary dramatically from system to system.