Difference Between Lte And Lte Advanced Pdf
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Joint processing JP in CoMP technology provides multiple data transmission points for each user among multiple cooperated radio base stations. Hard handover mechanism is adopted to be used in LTE-Advanced.
- 4G: LTE/LTE-Advanced for Mobile Broadband
- Limited Comp Handover Algorithm For LTE-Advanced
- Is LTE 4G? What is difference between LTE and LTE Advanced?
- LTE (telecommunication)
It increases the capacity and speed using a different radio interface together with core network improvements. The different LTE frequencies and bands used in different countries mean that only multi-band phones are able to use LTE in all countries where it is supported. The standard is developed by the 3GPP 3rd Generation Partnership Project and is specified in its Release 8 document series, with minor enhancements described in Release 9.
4G: LTE/LTE-Advanced for Mobile Broadband
Joint processing JP in CoMP technology provides multiple data transmission points for each user among multiple cooperated radio base stations.
Hard handover mechanism is adopted to be used in LTE-Advanced. While the radio resources in the system are fixed, the more multiple data connections a user has, the more radio resources are used for the extra data connections, thus the lower capacity a system becomes.
System performance of Limited CoMP Handover Algorithm is evaluated and compared with open literature handover algorithm via simulation in this paper. The simulation results show that Limited CoMP Handover Algorithm outperforms open literature handover algorithm by having shorter system delay and less system load whilst maintaining a higher system throughput in a high congested network.
LTE-A is a purely packet switched radio access technology that supports higher capacity, coverage, and data rates i.
OFDMA is a multicarrier access technology that divides the wide available bandwidth into multiple equally spaced and mutually orthogonal subcarriers. There are a number of key features introduced in LTE-A, including carrier aggregation, downlink and uplink spatial multiplexing enhancement, coordinated multipoint CoMP transmission and reception, relaying nodes, and heterogeneous networks compatibility [ 6 ].
Carrier aggregation permits an eNodeB to group several distinct channels into one logical channel. Downlink spatial multiplexing using up to eight-layer multiple-input multiple-output MIMO and uplink spatial multiplexing using four-layer MIMO increase average and peak data rate and the cell edge throughput [ 7 ]. Both Relaying nodes and heterogeneous networks compatibility provide coverage and capacity in areas difficult or expensive to reach using the traditional approach.
Handover is a mechanism that transfers an on-going call or data session from one base station BS to another BS hard handover or one sector to another sector within the same BS soft er handover.
Hard handover refers a UE starts handover to the target cell by breaking the current existing connection with the source cell before having a new connection with the target cell. Unlike hard handover, soft er handover makes the possibility for a UE simultaneously to connect to two or more cells or cell sectors during a call or data session.
Handover in LTE-A is a hard handover [ 9 ]. A single connection for each UE connected with the source eNodeB at any time instant is restricted by the nature of hard handover mechanism. A handover mechanism in CoMP is purposed in [ 10 ] to solve the conflict. A handover algorithm is needed and used for making a handover decision in handover mechanism.
The simulation results have shown that when compared with the standard handover algorithm in LTE system, CoMP Handover Algorithm in LTE-A is able to improve system throughput and minimize packet loss rate PLR ; however this algorithm could lead to system capacity overload and saturated system throughput issues within a high congested network.
While the radio resources in the system are fixed, the more multiple data connections a UE has, the more radio resources are used for the extra data connections, thus the lower capacity a system becomes. The performance metrics used for evaluation and simulation environment are discussed in Sections 3 and 4 , respectively.
Section 5 contains results of the performance evaluation, and conclusions are summarized in Section 6. A serving cell is the cell which takes the responsibility for making handover decision and maintains the connection of each UE to the network. A UE can only attach to one serving cell at each time instant. A CCS is a set of cells which are selected by the serving cell from the measurement set. A measurement period is a time period that is used for checking the handover condition periodically [ 13 ].
A handover margin is a constant variable that represents the threshold for the difference in reference signal received power RSRP between the serving and the target cells.
HOM helps in identifying the most appropriate target cell that a mobile can be handed over to. When a mobile is experiencing this effect, it is handed over from a serving cell to a target cell and handed back to original serving cell again in a small period of time [ 15 ]. This effect increases the required signalling resources, decreases system throughput, and increases traffic delay caused by buffering the incoming traffic at the target cell when each handover occurs.
The complete handover decision algorithm is illustrated in Figure 3. Then UE starts to feed back the serving cell with the measurement set which is the RSRP measurements received from all cells in the network. The first measurement period expires immediately due to an update required for the new incoming UE. When the regular measurement update is required during the transmission, the selection of CCS and CTP for each UE will be repeated by the serving cell to search for updated target cells.
Once handover is triggered, the serving cell sends a cancellation message to each of the cell in CTP to cancel the current transmission. A handover command is triggered to instruct the UE to handover to the future serving cell.
A complete flowchart of the algorithm is provided in Figure 4. A serving cell takes the responsibility for making handover decision for each UE in the network.
The same three variables in Section 2. A measurement period acts like a time period that is used for checking the handover condition periodically. A handover margin is a constant variable that represents the threshold for the difference in RSRP between the serving and the target cells. UE gathers measurement reports which are the RSRP measurements received from the measurement set and feeds the reports back to the serving cell.
A handover is triggered if 3 is satisfied within TTT duration. The serving cell sends out a handover command to instruct the UE to handover to the future serving cell.
Lastly, UE detaches from the network and camps on a new serving cell after the interruption time the time period during which UE disconnects from the network. CTP starts transmitting data to the UE and waits for the next incoming measurement period expired if 2 is not satisfied at any point in time during TTT duration. When the measurement period is not expired, the serving cell directly performs the CTP selection Step 6 in Figure 5. CTP continues transmitting data to the UE and repeats this process until the next measurement period expires.
Note that the red solid line, the blue dash line, and the black long dash dot line in Figure 5 indicate the directions in time domain of measurement period, each other time instant, and both, respectively. As described in Section 2. CoMP Handover Algorithm improves the system throughput by giving multiple connections to each UE at any time instant regardless of their channel condition, but this mechanism also accelerates the current system capacity multiple times as fast reaching its maximum capacity due to the multiple connections needed to be maintained for each UE in the network.
Therefore CoMP Handover Algorithm leads to system capacity overload and saturated system throughput issues within a high congested network. Limited CoMP Handover Algorithm comes with the concept of having multiple transmissions for each UE when necessary in order to extend the system capacity as high as possible.
Thus the multiple data transmissions for cell-center UEs should be avoided in order to prevent the radio resources overused in other target cells in CTP based on the concept of Limited CoMP Handover Algorithm.
Thus Limited CoMP Handover Algorithm has to provide multiple data transmissions for cell-edge UEs to maintain their quality of connections while they are staying in cell-edge areas. This mechanism Step 6 in Figure 5 helps in eliminating inefficient data transmission at any time instant in the network; therefore Limited CoMP Handover Algorithm is able to maintain the available radio resources more efficiently. Steps 1 and 2 in both algorithms are the ordinary information gathering procedures.
Similarly, Step 3 performs a standard periodical measurement check in both algorithms. Steps 6 to 9 in Figure 4 and Steps 8 to 11 in Figure 5 are identically the same where both algorithms transmit data from CTP to UEs if the handover condition check in Step 5 in Figure 4 and Step 7 in Figure 5 was not satisfied; otherwise serving cell sends out handover control messages in CTP for UE to be handed over to future serving cell. Lastly, UE detaches the network and repeats the cell re selection Step 1 in Figure 4 and Figure 5 in both algorithms.
Detailed descriptions of each metric are provided below. RB Utilization evaluates the proportion of total used RBs to total RBs in each cell and describes the current load state of the cell. A higher RB Utilization indicates a higher saturated state the cell becomes; therefore a cell reselection needs to be considered when more UEs are going to be handed over to this cell.
On the other hand, when the cell is having a lower RB Utilization, this cell is capable of accommodating more incoming UEs. RB Utilization can be mathematically expressed as where is the total number of cells, represents the total simulation time, denotes the total resource block used of cell at time , and denotes the total resource of cell at time. System throughput is defined as the total number of bits correctly received by all users and can be mathematically expressed as where is the total number of UEs, represents the total simulation time, and denotes the number of transmitted bits of cell whichever earlier received by UE at time.
System delay gives the average of the total queuing delay of all packets in the buffers at the eNB in the system. System delay can be mathematically expressed as where is the total number of UEs, represents the total simulation time, and denotes the delay of the HOL packet of cell whichever earlier received by UE at time. Users are uniformly distributed within the rectangle area as shown in Figure 6.
Each eNodeB is located at the center of each cell with meter radius, and equal transmit power A reflect wraparound method is applied when each UE reaches the system boundary. The maximum number of retransmissions is limited to 3. Round robin is selected as packet scheduling algorithm is to ensure the equal fairness for each UE in the system.
The complete system parameters used in the simulation are listed in Table 1. Each performance metric is separately discussed in the following subsections. The system becomes saturated after the number of UE is equal to in both algorithms.
The overall trend of system throughput increases in both algorithms when the number of UEs increases because the more UEs coming in the simulation, the more successfully transmit packets from all UEs in the system. According to 5 , the higher the number of transmitted bits in the system is, the higher the system throughput it becomes.
CoMP Handover Algorithm provides better system throughput as On the other hand, Limited CoMP Handover Algorithm restricts the number of data connections for each UE at any time in the system based on their channel condition.
This restriction frees the available RBs of the second data connection from the cell-center UE, and the freed available RBs can be further used for other new incoming UE which improves more transmit packets in the system and therefore enhances the system throughput. When the system becomes saturated, the system throughput stops increasing due to insufficient radio resources RBs to be allocated to the UEs in the system.
A too late handover will affect the channel condition of the UE and also a too late handover would be more likely leading to a radio link failure situation where the packets of the UE cannot be correctly received which reduces the system throughput. The overall trend of system delay increases in both algorithms when the number of UEs increases because the more UEs are coming in the simulation, the more condensed the system becomes where all the packets need to be buffered longer in the queue to get transmitted to all the UEs, which leads to higher system delay.
CoMP Handover Algorithm has lower system delay as CoMP Handover Algorithm has higher system delay as This behaviour increases the loading and the queuing delay of both of the serving cell and the target cell in CTP which leads to higher system delay. Therefore this UE will not increase the loading and the queuing delay of the target cell in CTP which leads to a lower system delay result. A new handover algorithm named Limited CoMP Handover Algorithm is proposed in this paper and its impact on a number of optimized handover parameters under the downlink LTE-A system is evaluated.
It is shown via simulation that the proposed handover algorithm can improve the system throughput compared to CoMP Handover Algorithm in a saturated system when UE is equal to , , , and The proposed handover algorithm is able to maintain a lower system delay when compared with CoMP Handover Algorithm. Moreover, the system throughput and system delay of proposed handover algorithm can be further improved by optimizing the HOM variable.
Evaluating the performance of the proposed handover algorithm under different wireless scenarios and taking QoS requirements of multimedia services under consideration will be the focus of the future studies.
This is an open access article distributed under the Creative Commons Attribution License , which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Journal overview. Special Issues. Academic Editor: Stavros Koubias. Received 31 Aug Revised 17 Dec
Limited Comp Handover Algorithm For LTE-Advanced
LTE represents a radical new step forward for the wireless industry, targeting order-of-magnitude increases in bit rates with respect to its predecessors by means of wider bandwidths and improved spectral efficiency. Beyond the improvement in bit rates, LTE aims to provide a highly efficient, low-latency, packet-optimized radio access technology offering enhanced spectrum flexibility. The LTE design presents radical differences at every layer. Like many other communication technologies e. In terms of radio access, CDMA has given away to time and frequency multiple access. At the network layer, a flatter architecture is being defined that represents the transition from the existing UTRA network, which combines circuit- and packet-switching, to an all-IP system. The objective of this special issue is to disseminate new advances in both the physical and medium access control layers that are applicable to the LTE and LTE-Advanced technologies.
Is LTE 4G? What is difference between LTE and LTE Advanced?
This paper offers an introduction to the mobile communication standard known as LTE Advanced, depicting the evolution of the standard from its roots and discussing several important technologies that help it evolve to accomplishing the IMT-Advanced requirements. A short history of the LTE standard is offered, along with a discussion of its standards and performance. LTE-Advanced details include brief history of the standard, technical requirements, as well as analysis on the physical layer, resource control, and performance.
The architecture used in LTE was designed to surpass the mobile data rates that were available using 3G technologies. This simplified, flatter version of the network architecture mean response times are much quicker and therefore users of the network would realise much better data rates. The main aim for LTE-A Pro is to increase the data speeds and bandwidth that are currently available for mobile communications.
This ongoing race of increasing sequence numbers of mobile system generations is in fact just a matter of labels. What is essential is the actual system capabilities and how they have advanced. The evolution of 3G systems into 4G is powered by the creation and growth of new services for mobile devices, and is enabled by advancement of the technology available for mobile systems. There has also been an evolution of the environment in which mobile systems are deployed and operated, in terms of levels of competition between mobile operators, challenges from other mobile technologies, and new regulation of spectrum use and market aspects of mobile systems.
To move to higher-speed networks that can cater to customer demand for mobile broadband multimedia applications, the 3GPP has developed the latest LTE-Advanced LTE Release 10 standard, which will be fixed in December This book focuses on LTE and LTE-Advanced, and provides engineers with real insight and understanding into the why and how of the standard and its related technologies. This book is written by engineers from Ericsson--the world's leading telecommunications supplier--who was heavily involved in the development of the standard. Erik Dahlman works at Ericsson Research and are deeply involved in 4G and 5G development and standardization since the early days of 3G research. Stefan Parkvall works at Ericsson Research and are deeply involved in 4G and 5G development and standardization since the early days of 3G research. Johan Skold works at Ericsson Research and are deeply involved in 4G and 5G development and standardization since the early days of 3G research.
One of the key factors for the successful deployment of mobile satellite systems in 4G networks is the maximization of the technology commonalities with the terrestrial systems. An effective way of achieving t Content type: Research Article. Published on: 5 November We present a design of a complete and practical scheduler for the 3GPP Long Term Evolution LTE downlink by integrating recent results on resource allocation, fast computational algorithms, and scheduling. In data packet communication systems over multipath frequency-selective channels, hybrid automatic repeat request HARQ protocols are usually used in order to ensure data reliability.
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