LTE OFDMA and Downlink Frame Structure Details Downlink OFDMA time-frequency multiplexing LTE Spectrum Flexibility and Bandwidth FDD downlink frame structure detailed TDD frame structure LTE (any OFDM/OFDMA) band is made up of multiple small spaced channels and we call each of these small channels as “Sub Carrier”. Space between the chhanel and the next channel … Read more
Power control – already being applied in 2nd and 3rd generation networks – has high potential for improvement of the performance of mobile networks. Main benefits are: 1. It can bring down the interference in up- and downlink and hence enhances the capacity of the networks. 2. Additionally it helps to keep down the uplink-power … Read more
CDMA extends the idea of diversity reception with the concept of soft handoff. In the slide, a mobile CDMA phone has established a call with base station one. As the mobile moves away from base station one and approaches base station two, a device in the phone known as the searcher identifies base station one … Read more
IP Networks use Routers to do the switching based on IP addresses, Layer 3 routing protocols like BGP or OSPF an Ethernet networks use 48 bit MAC addresses Spanning Tree is used to route because users, base stations, routers, etc will all need IP addresses (It is an IP-based system) There are Public (Internet routable) … Read more
The control plane includes the application protocol. It also includes the signaling bearers for transporting the application protocol messages. The application protocol is used for setting up bearers in the radio network layer. For example, radio access bearers or radio links. Figure shows “Control plane protocol stack” comprises Radio Resource Control (RRC), Packet Data Convergence … Read more
LTE RAN provides the physical radio link between the User Equipment (UE) and the Evolved Packet Core (EPC) network. LTE RAN comprises eNodeBs. The eNodeB contains Transmit Receive Duplex Units (TRDUs) or Remote Radio Heads (RRHs) and communicates with the UEs. The eNodeB supports Multiple Input Multiple Output (MIMO). The LTE RAN – eNodeB provides: … Read more
Here i write very small notes about How Seamless Handover in LTE which is very basic and some require techniques for real time data handover in LTE. Seamless handover is applied for user plane radio bearers mapped on RLC unacknowledged mode. These types are usually quite tolerant of losses, but less tolerant of delay (e.g. … Read more
Closed Subscriber Group LTE supports the existence of cells which are only available for a limited set of EEC- A closed Subscriber Group (CSG). In order to prevent attempts to register on the UES CSG cells on which they do not have access to, up to the CSG supports white list, that is, a list … Read more
Cell selection consists of the UE seeking stronger cell on all supported frequencies of each transport supported rat until it finds a suitable cell. The main requirement for cell selection is that it should not take too much time that becomes more difficult with the growing number of frequencies and rats to be searched. The … Read more