In any two-way radio system, the radio pathlosses and the equipment output powers and sensitivities must be taken into account for both directions. This is especially true in a mobile network (e.g. downlink: BS to UE and uplink: UE to BS), where there are different characteristics for the uplink and downlink paths. These include, for … Read more
When the radio wave propagates in the air, the electric field direction changes regularly. If the electric field direction of radio wave is vertical to the ground, the radio wave is vertical polarization wave If the electric field direction of radio wave is parallel with the ground, the radiowave is horizontal polarization wave Propagation of … 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
Frequency diversity is inherent in a spread spectrum system. A fade of the entire signal is less likely than with narrow band systems. Combats Fading, Caused by Multipath Fading Acts like Notch Filter to a Wide Spectrum Signal May Notch only Part of Signal Fading is caused by reflected images of an RF signal arriving … 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
The LTE related core network evolution is referred to as Evolved Packet Core (EPC). LTE architecture is based on the system architecture evolution (SAE) model defined by the 3G Partnership Project (3GPP). EPC consists of the following network elements: Mobility Management Entity The Mobility Management Entity (MME) is the LTE mobility management and session management … Read more
One of the main functions of the PDCP header compression is using Header Compression (ROHC) robust protocol defined by IETF (Internet Engineering Task Force) . In LTE, header compression is very important because there is no support for transport of voice circuit-switched (CS) domain. Thus in order to provide voice services (PS ) domain Packet … Read more
Here I write on How Inter-RAT Mobility performs in LTE, means Handover to LTE and Mobility from LTE. Handover to LTE Procedure for handover of LTE is largely the same as the handover procedure in LTE. The main difference is that the handover to LTE AS a whole-configuration must be signaled, and the LTE it … Read more