Broadband Access Technology (Wireless Access Technology) Lecture

Broadband Access Technology (Wireless Access Technology) Dr. Nora Ahmed Ali Communications Technology Department Egyptian Chinese Collage for Applied Technology, ECCAT Suez Canal University 1 ...

Broadband Access Technology (Wireless Access Technology) Dr. Nora Ahmed Ali Communications Technology Department Egyptian Chinese Collage for Applied Technology, ECCAT Suez Canal University 1  Low Range wireless technologies 2 3 4 5 6 LTE (LONG TERM EVOLUTION) 7 WHY LTE 8 LTE FEATURES Parameter Details Peak downlink speed with 64QAM in Mbps 100 (SISO), 172 (2x2 MIMO), 326 (4x4 MIMO) Peak uplink speeds(Mbps) 50 (QPSK), 57 (16QAM), 86 (64QAM) All packet switched data (voice and data). No Data type circuit switched. Channel bandwidth (MHz) 1.4, 3, 5, 10, 15, 20 Duplex schemes FDD and TDD 0 - 15 km/h (optimised), Mobility 15 - 120 km/h (high performance) Idle to active less than 100ms Latency Small packets ~10 ms Downlink: 3 - 4 times Rel 6 HSDPA Spectral efficiency Uplink: 2 -3 x Rel 6 HSUPA OFDMA (Downlink) Access schemes SC-FDMA (Uplink) QPSK, 16QAM, 64QAM (Uplink and Modulation types supported downlink) 9 LTE RADIO FREQUENCY 10  Spatial Multiplexing (MIMO) 11  Spatial Multiplexing (MIMO) 12  What is 4G Technology IP based packet switching network It supports high data rates (1Gpbs for fixed services and 100 Mbps for mobile services) Seamless connectivity and global roaming with smooth handovers ITU has approved two technologies as 4G  LTE-Advanced (3GPP Release 10 -2011)  WiMAX Release 2 (IEEE 802.16m – 2011) 13  LTE-Advanced and Features) (Specifications Data rates reaches to 3Gbps for downlink using 100 MHz bandwidth High order MIMO (8Χ8) High spectral efficiency, 30 bps/Hz using 8Χ8 MIMO downlink and 15 bps/Hz using 4Χ4 MIMO Lower latency compared to LTE High Mobility: up to 500 km/hr Spectrum flexibility: FDD and TDD and wide range of radio spectrum High Bandwidth: reaches to 100 MHz 14  Key Factors The main factors that differentiates between LTE-advanced and LTE technologies: 1. Spectrum with respect to band and bandwidth (Carrier Aggregation) 2. Spectral efficiency (high order MIMO – enhanced interference mitigation techniques) 3. Edge user performance (Coordinated multipoint ) 4. Cell sizes (home eNBs, Heterogeneous network) 15  Carrier Aggregations LTE-Advanced supports a maximum bandwidth of 100 MHz This is an extremely large bandwidth, which is most unlikely to be available as a contiguous allocation To solve this problem, LTE-Advanced allows a mobile to transmit and receive on up to five component carriers (CCs), each component has a maximum bandwidth of 20MHz. This technique is known as Carrier Aggregation 16  Carrier Aggregation In Carrier Aggregation, there are three scenarios: Contiguous Intra-band aggregation, Non- Contiguous Intra-band aggregation and Inter- band aggregation as shown on the following figure 17  Coordinated Multipoint (CoMP) Transmission and Reception When the mobile user moves from base station’s antennas and towards the edge of the cell, it will receive a weaker signal from the serving cell and more interference from other cells that are nearby These two effects reduce the user’s data rates and degrade the performance CoMP transmission and reception technique is obtained to improve the performance of the cell edge user and consequently increases cell edge spectral efficiency 18  Coordinated Multipoint (CoMP) Transmission and Reception In this technique, nearby antennas cooperate so as to increase the power received by the mobile user at the cell edge, reduce its interference and increase its achievable data rate 19  Heterogeneous Network Deploying the low power nodes or changing cell sizes is one of the main things that differentiates LTE-A network from LTE network. Deploying the low power nodes with macrocells (default cell) is known as heterogeneous network According to 3GPP, the heterogeneous network is defined as the networks of different types of cells or the networks of base stations of different transmission power. Therefore, the LTE-A network or the 4G mobile network is known as the heterogeneous network. 20  Heterogeneous Network The main objective of deploying the low power nodes with macrocells is improving the coverage and the capacity. Improving the coverage comes from the ability of deploying low power nodes in anywhere, where it can be deployed in dead zones that are not covered by the macrocells Improving capacity comes from offloading some data traffic from the macrocells. There are different types of low power nodes such as picocells, femtocells (Home eNBs) and relays and they are described later 21  Heterogeneous Network 22  Picocells Picocell: It is deployed by operators for outdoor environment to improve the network coverage and the capacity. It operates with low transmission power (in range 23-30dBm) and coverage in range of 100 meter. It allows open access for all users when the capabilities of macrocell are insufficient. It is connected to the core network via coaxial cable or fiber 23  Femtocells (Home eNBs) Femtocell: It is called Home enodeB (HeNB). It is deployed by the end user for indoor environments such as offices and homes, it can be deployed anywhere to cover the dead zone areas. It has low transmission power in range 23dBm and its coverage cannot exceed 50 meter. It connects to the core network through an IP network such as DSL and has no direct interface to macrocells. 24  Femtocells (Home eNBs) It can operate in three different modes closed, open or hybrid. In closed mode, only predefined subscribers have access and permission to connect to femtocell, these subscribers located in a group that is called Closed Subscriber Group (CSG). Open mode provides access for all users and all users in the network have the right to connect to femtocell. Hybrid mode provides high service quality for the subscribed users and limited access for the other users 25  Relays Relays: They are access points deployed by the operator and used to route the data from the macrocells to the users in new areas in order to extend the system coverage. Also, it enhances the performance at cell edges They have limited capabilities compared to the pico and femto cells 26  Comparison between LTE and LTE-A 27