Carrier components assignment method for LTE and LTE-A systems based on user profile and application
Summary (3 min read)
Introduction
- Therefore, the bandwidth demand for mobile Internet access is getting exponentially larger [3].
- Results show that the proposed CCs assignment method uses system resources efficiently and can provide improved throughput rate in LTE and LTE-A.
- In Section V, simulation results are analyzed.
II. SYSTEM MODEL AND USER PROFILE
- In Fig. 1, User Equipments (UEs) are mobile.
- UEs can connect one band or multi bands simultaneously based on coverages of bands and UEs’ positions.
- Above scenarios show the importance of management of CCs in LTE and LTE-A in order to increase performance.
A. System Model
- Fig. 2 shows system model for a CCs assignment method.
- One to two of CCs are primary component carrier (PCC) for DL and UL, and can only be updated during handover [4], but the rest of CCs can be dynamically assigned to each UE in specified time interval [19].
- Determining the number of required CCs and band of each CCs for each UE does not only decrease power consumption and interference but also increase efficiency of CCs resources usage.
- Estimating RT and NRT data usage for a UE helps an eNB arrange the number of CCs and their bandwidth sizes, and estimating mobility of a UE reduces handover overheads and risk of connection lost.
- It is important to note that the user profile can be used with any existing CCs assignment methods.
B. User Profile Detection Based on Services
- Historical data usage information of each UE plays crucial role to identify user profiles.
- As shown in Table II, each UE holds Times, Connection Time (Con. T) and Idle Time (Idle T.), RT and NRT services data sizes for each eNB.
- In order to identify user profile from Table II, some statical analysis such as percentage measurement, can applied.
- CCS ASSIGNMENT METHOD FOR LTE\LTE-A SYSTEM Fig. 3 illustrates the proposed CCs assignment method in LTE systems.
- Simply, the proposed method firstly finds the number of required CCs and bands of CCs, and assigns them to each UE.
A. Assumptions for eNBs
- While implementing simulation, it is assumed that there is only one eNB which has three bands to provide service to UEs.
- CCs for NRT and RT services and their sizes and quantities are given in Table III.
- The sizes and quantities are arranged based on the 800MHz, 1.8GHz and 2.6GHz.
- To reach required data rate for LTE systems, 10MHz bandwidth is chosen for NRT services and 20MHz bandwidth is chosen for RT services from Band-b and Band-c, and only 10MHz bandwidth is chosen for RT and NRT services from Band-a because PCC is generally chosen from a band which has higher range like Band-a.
- In addition, bandwidth size of NRT type CCs is 10MHz because RT traffic data usage is more common than NRT data usage for mobile devices.
B. Assumptions for UEs
- There are three types of UEs, LTE, LTE-A low and LTE-A full capacities in the system.
- UEs are uniformly distributed in area and UEs can use one or multi bands.
- Packet arrivals follow Poisson distribution and arrival rates of traffic are getting higher when the number of users is increased.
- Selected Transmission Time Interval (TTI) for a packet is 1ms.
C. Observation Methodology
- The simulation results in Section V are average of 1000 simulation runs for different UEs size.
- Only data usage estimation based on user profile is used with simple mobility estimation in order to show effects of the proposed method on R method.
D. Packet Scheduling
- Without packet scheduling, the result cannot be obtained.
- Therefore, the authors have used a simple packet scheduling method in order to compare RSA and UPRs (UPRs represents UPR, UPR10 and UPR25 together).
- For test case, predetermined static number of CCs is four for RSA because maximum number of CCs for each UE is five in LTE systems and one of them must be used for PCC (see Section II).
- RSA and UPRs transfer each packet by using one of assigned CCs.
- If there are multiple available CCs from different bands, firstly CCs which belongs to lower range band (Band-c) are preferred to transfer the packet in order to decrease traffic loads to higher range band (Band-a).
V. RESULTS
- Utilization of bands is measured by dividing total packets of active users in each CC to total capacity of CCs in each band then averaging the result with total time steps (simulation time/10ms).
- Throughput rates are measured by dividing transferred packets to all generated packets for NRT and RT.
- Therefore, while increasing number of UEs, throughput of traffic decreases for each UE.
- By these comparisons, resource usage and managed QoS can be compared.
- The method which has lower resource usage and higher throughput with equal fair service between device types is better.
A. Utilization
- Figs. 4, 5 and 6 show the utilization for Band-a, Band-b and Band-c, respectively, obtained for RSA and UPRs.
- If utilization of Band-a, Band-b and Band-c are compared, it is observed that while the number of UEs is getting higher, utilization of all bands is gradually increasing for all cases.
- Utilization of Band-a is increasing faster than utilization of Band-b, utilization of Band-b is increasing faster than utilization of Band-c for all cases.
- There are three reasons for it: (i) bands which have higher range are used more than bands which have lower range, (ii) distribution of UEs around the eNB increases probability of lower amount of UEs located in bands which have lower range and vice verse, and (iii) CCs assignment based on R method without considering CCs loads.
- Bands utilization results of UPRs are close to each other for all bands while even error rate is increased to %10 and %25.
B. Throughput Rate
- While the number of UEs is increased, throughput rate per UE is decreasing for both traffic type.
- While user profile has error rate up to %25, throughput rates of UPRs are almost equal and higher than RSA for NRT and RT traffics.
- When the number of UEs is reached to 250, NRT throughput are almost equal for all cases.
C. Fairness
- Fig. 9 show the service fairness between device types.
- L represents LTE and LTE-A-Low capacity devices while F represents LTE-A full capacity devices.
- By using RSA, LTEA full capacity devices get more service than LTE and LTE-A low capacity devices.
- UPRs are capable to fairly distribute service to UEs.
VI. CONCLUSION
- The authors have proposed a carrier component assignment method for LTE and LTE-A systems by considering user profiles.
- Throughput of non-real time and real time traffic, and bands utilization have been compared through extensive simulations.
- Results show that the proposed method uses system resources efficiently and provides improved user throughput rate and utilization in LTE and LTE-A systems.
- The proposed method and related analysis will help service providers build efficient LTE-A systems architectures which are adaptable to LTE and LTE-A type devices by considering user profile, traffics and bands performances, such as throughput and utilization.
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Citations
9 citations
Cites background or methods from "Carrier components assignment metho..."
...However, neither we have considered CQI and load balance properties for user profile carrier assignment method nor joint and partial carriers assignment techniques [4], [22] are investigated in user profile carrier assignment method....
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...Finally, Section VI has the concluding remarks....
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...Therefore, user profile, in addition to CQI, can be considered to increase QoS and Quality of Experience (QoE)....
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2 citations
Cites background or result from "Carrier components assignment metho..."
...In contrast to the previously stated work, the authors in [30] did not consider the channel quality instead decision on the number CCs of required by the newlyarrived LTE-A user was made on the basis of its profile (i....
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...Algorithm in [30] • Determine the required number of CC based on user profile....
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1 citations
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...Here, the threshold can be dynamically arranged by using user profile information for each user as is done in our past work [13]....
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...capacity in terms of LTE, LTE-A low capacity, and LTEA full capacity, (LTE-A low capacity should be considered because multi-CCs assignment needs more memory and power for processing [5]....
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...mobility of users, traffic types and assigned channel errors, the best available Carrier Components (CCs) of each band should be assigned to each user to increase quality of services [5]....
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267 citations
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...Size of NRT and RT packets is 512 bytes [22]....
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