This confirms that the thesis submitted by Kazi Naws/utd Azain entitled Jntelligent Inteiference Management for Dense Femtocellular Networks" has been approved by the review board for partial fulfillment of the requirements for the M.Sc. The simulation results show that the proposed ODSC scheme in femtocell implementation significantly improves the performance of the SNIR level, throughput, probability of failure and reduces the probability that a FAP has no user in the multi-story building or the home environment.
Nomenclature
Introduction
Problem statement
- Literature review
Besides this active mode of FUE, there are two more modes of FUE that are considered in the proposed ODSC scheme. In [7], the main issue of mobility management for the integrated fcmtoccll/macrocell network is presented.
Research objectives
- On-demand issues in femtocellular networks
- Probability of outage reduction of the femtocell users
These two problems can be intelligently reduced by using an ODSC scheme where the femtocell serves its users when the demand for them is generated. By using the proposed ODSC scheme, it is possible to reduce the probability of outage along with interference and unwanted HO problems.
Thesis outline
In this ODSC scheme, FAP stays ahead of demand creation in low-power FIM and searches for any active femto user that can request to be served by the FAP. Since low power condition of the FAP causes less possibility of interference, the proposed ODSC scheme is therefore more efficient for dense femtocell network deployment.
Femtocell Overview
Advantages of femtocell
Reduced congestion of mobile networks: The implementation of Femtocell networks in combination with macrocell can relieve some of the macrocell users. Call access control: The implementation of Femtocell networks in combination with MBS 1 requires control over the access of calls between these two networks.
Type of femtocell deployment with macrocell
HO management: The frequent unwanted control of HO is another problem in femtocell deployment that remains to be solved. Interference Management: In order to provide satisfactory network services to femtocell users, interference in the system must be kept to a minimum. This type of ferntocell placement is responsible for a moderate interference effect in the system because each fcmtocell in the network has more than one fcmtoccll neighbor in the near area and they (FAP# 17 to FAP# 24) are unplannedly installed by femto users.
Dense deployment of femtocell (FAP# 1 to FAP# 16) is more challenging because many considerations are needed around resource allocation, network planning, capital cost, interference effect, unwanted HOs, failure probability and regulatory policy.
Interference in Femtocell
- Scenario of interference in fenitocell
- Source of interference
- Effect of interference in femtocell
- Different solutions to mitigate interference effect in femtocell
- Interference effect of dense femtocell deployment in macrocell
Whenever the MUE is close to the femtocell or within the coverage area of the femtocell, the UL signal transmitted from the MUE to the MBS causes interference for the FAP receiver. Whenever the femtocell is close to the macrocell, the UL signal transmitted from the FUE to the FAP causes interference to the macrocell receiver. Both schemes effectively compensate for the UL throughput degradation of the existing MBS due to cross-layer interference.
Calibrations of femtocell DL transmit power to limit interference to the macro network while providing good coverage for the femtocell user. Limiting a femtocell user's UL transmit power to minimize the interference caused by the macro network's UL.
On-Demand Service Connectivity (ODSC) Scheme
Tabular representation.of the ODSC scheme and FAP continuous servke scheme
Also, the communication statuses of the reference NMSs together with all MUEs, as well as with some FUEs are given in Table 4.1 and Table 4.2. Here, to indicate the power mode of FAPs, FUEs and MUEs, a common superscript notation in Table 4.1 and Table 4.2 is used. FAP-to-FAP communication exists at all times, regardless of whether there is an active FUE or not.
From Table 4.2 it can be seen that FAPs are in active mode when they should be active.
Basic architecture of the ODSC scheme
When an active femto user exists in the new FAP coverage area, the connection quality between femto user and FAP, between FAP and. When an active feintocell user meets all conditions of the femtocellular system regarding a successful HO process under active FAP, then active FAP is ready to initialize an HO process using FGW, cisc HO processes are aborted . After successful HO, the whole process repeats for other active femtocell users, otherwise active FAP goes to inactive mode if no active femtocell user exists in it.
Sizing the system/network area Check neighbor FAP list and signal strength, distance to make decision.
Working process of the ODSC scheme
In this case, the reference FAP is initially in the FIM, so the change of its mode from idle to active occurs before the source of the HO request is checked. It is obvious from this simple example that sometimes there are chances of a pending HO request. If the HO request is a new request, refer to the FAP server responses to the new HO request.
Otherwise, if the HO request is a pending request, then refer to the FAP's pending HO request responses. If there is no HO request after receiving all HO requests, then the reference FAP repeats the HO request search procedure with FIM or FAM depending on the request of the current state of the reference FAP.
Mathematical Model for Capacity Analysis
SNIR and capacity analysis
POUtfi, =P(SNIR Considering in the typical scheme all interfering neighboring active femtocells and interfering reference rnacrocells, the outage probability can be expressed [4] as. Considering in the proposed scheme half of all interfering neighboring active femtocells and the interfering reference macrocell, the outage probability can be expressed as. Considering in typical scheme all the interfering neighbor active femtocells and interfering reference rnacrocell, the probability of interruption can be expressed [4] as. where i is the probability of failure of an active FUE under coverage area of reference active FAP in single power mode FAP deployment with all neighboring active FAPs. Considering the proposed scheme half of all the interfering neighboring active femtocells and interfering reference macrocell, the probability of interruption can be expressed as. where 1 is the probability of failure of an active FUE under coverage area of reference active FAP in dual power mode FAP deployment with all neighboring active FAPs. SNIR analysis with (a) the probability that a neighboring FAP is in active mode, (b) the number of neighboring active FAPs. 6.1(b)] the SNIR maximum and minimum occurs at zero and fifteen (randomly selected) neighboring active FAP points, respectively, describes the wide range of throughput variation. The higher value of SNIR in the ODSC scheme ensures less interference effect on the service of each active FUE with active FAP reference. Throughput analysis with (a) probability of a neighboring FAP being in active state, (b) number of neighboring active FAPs. Here, the probability of failure of the referenced active FAP in the single power mode is initially very low and gradually increases as all adjacent FAPs are active. However, the probability of failure curve for active FAP with dual power mode reference remains almost close to the zero probability line because all neighboring FAPs are in idle mode and are always smaller than that of other schedule curves. 6.3(b) shows the probability of failure of an active FUE within the coverage area of reference active FAP of dual power mode with 50% adjacent inactive FAPs and single power mode with all adjacent active FAPs, respectively. Here, the failure probability of the active FUE in the coverage area of the reference active FAP with single power mode is the same as that shown in Figure 6.3(a), but the failure probability curve in the reference active FAP with dual power mode is larger than in Figure . Probability of FAP activity analysis for K=1 and FUE30 with (a) average active period for each FUE. Probability of FAP activity analysis for K=3 and FUEz30 with (a) average active period for each FUE in one day, (b) number of FAPs for an average active period of 8 hours for each FUE in one day. Probability of FAP activity analysis for K=6 and FUE=30 with (a) average active period for each FUE in one day, (b) number of FATs for an average active period of 8 hours for each FUE in one day. Probability of FAP activity analysis for K=l and FUE=50 with (a) average active period of each FTJE in a day, (b) number of FAPs for average active period of 8 hours for each FUE in a day. Probability of FAP activity analysis for K=3 and FUE=50 with (a) average active period of each FUE in a day, (b) number of FAPs for average active period of 8 Firs for each FUE in a day. Probability of FAP activity analysis for K=6 and FUE=50 with (a) average active period of each FUE in a day, (b) number of FAPs for average active period of 8 hours for each FUE in a day. Probability of FAP activity analysis for K=6 and FIJE=80 with (a) average active period of each FUE in a day, (b) number of FAPs for average active period of 8 hours for each FUE in a day. The probability of failure observation curve for the second scheme is always higher than the proposed ODSC scheme performance curve. Based on the probability of activity of a FAP analyzed for different modes, proposed ODSC scheme shows little probability of FAP activity. Here, a small probability of FAP activity means less interference effect, which implies that a better frequency utilization can be ensured than conventional FAP implementation schemes. Then the simulation results from SNIR's Matlab are made, the throughput is presented and the observations of the outage probability are also given along with the activation probability of a FAP. From the activation probability of a FAP observation, it is clear that the energy consumption of FAPs is significantly reduced with the proposed ODSC scheme. Haas, "Interference Mitigation Using Dynamic Frequency Re-use for Dense Femtocell Network Architectures," in Proceeding of IEEE International Conference on Ubiquitous and Future Networks (1CUFN), Jun. Fourcstic, "Performance Evaluation of Frequency Planning Schemes in OFDMA-basecl Networks, " IEEE Transactions on Wireless Communications, vol. Lcung, "Dynamiese frekwensie-toewysing in fraksionele frekwensie hergebruikte OFDMA-netwerke," IEEE Transactions on Wireless Communications, vol. 34;Interferensievermyding met dinamiese interselkoördinasie vir downlink LTE-stelsel," in die vervolg van IEEE Wireless Communications and Network Conference (WC'NC'), Apr. Yanikomeroglu., "Enhancing Cell-Edge Performance: A Downlink Dynamic Interference Avoidance Scheme met inter-selkoördinasie", IEEE Transactions on Wireless Communications, vol. List of PublicationsProbability of activeness of a FAP analysis
Simulation Results
SNIR comparison
Throughput comparison
Probability of outage observation
SIlISI
Probability of activeness of a FAP observation
Conclusions
Discussion and recommendations
