lets talk about LTE Architecture- SERVICE, EPC, E-UTRAN and User Equipment. In the LTE network is divided into 2 basic networks, namely: 1. EUTRAN (Evolved Universal Terrestrial Radio Access Network) 2. EPC (Evolved Packet Core) SERVICE IP Multimedia Subsystem (IMS) is a good example of cars that can be used in the service layer connectivity Services … 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
Correlation Is a Measure of How Well a Given Signal Matches a Desired Code, The Desired Code is Compared to the Given Signal at Various Test times. Correlation is key enabling concept for direct sequence CDMA systems. Correlation is a measure of how well a given signal spread with a digital code matches a desired … Read more
The action of camping on provides access to services. The network provides different levels of service to a UE in either Idle mode or Connected mode. Three levels of services are defined: LIMITED SERVICE: emergency calls on an acceptable cell. Acceptable cell: UE may camp to obtain limited service like emergency call. The minimum set … Read more
Random access procedure is performed for the following five events: • Initial access from RRC_IDLE; • RRC Connection Re-establishment procedure; • Handover; • DL data arrival during RRC_CONNECTED requiring random access procedure; • UL data arrival during RRC_CONNECTED requiring random access procedure; E.g. when UL synchronization status is “non-synchronized” or there are no PUCCH resources for … Read more
PLMN Selection Process in LTE The UE scans all RF channels in the UTRAN band according to its capabilities to find available PLMNs. On each carrier, the UE searches for the strongest cell according to the cell search procedure (refer cell searching) and read its system information in order to find out which PLMN the … Read more
SRNC and DRNC are concepts for a connected UE. The SRNC handles the connection to one UE, and may borrow radio resources of a certain cell from the DRNC. Drift RNCs support the Serving RNC by providing radio resources A UE in connection state has at least one and only one SRNC, but can has … Read more
The UE is requested to send either periodic or a periodic reports concerning • Rank indication (RI) Reports are applicable for closed- and open-loop spatial multiplexing. In case of open-loop TRI=1 corresponds to transmit diversity and TRI>1 to large delay CDD. • Precoding matrix indicator (PMI) PMI reporting is relevant for spatial multiplexing (open- and … Read more
The scheduling is performed on cell basis. The two main functions are to decide which UE(s) shall be scheduled, the number of resources and the MCS to be applied. Furthermore the scheduler needs to be QoS aware. There is priority given to random access responses, control data, HARQ retransmissions. The channel quality may be taken … Read more
A variety of scheduling strategies is available in LTE. The scheduling strategy is based on a certain metric. – Round-Robin. No quality indication is taken into consideration. The resources are mainly shared in an equal manner. – Max C/I. The UE with the best channel conditions gets the highest priority. The cell throughput is maximized. … Read more