The Radio Resource Connection (RRC) protocol is implemented in the eNodeB and the UE. In WCDMA, it is implemented in the RNC! RRC is the highest protocol in the control plane on the radio side. The RRC protocol allows: 2 instances (eNodeB and UE) to exchange signaling messages. to forward signaling messages coming from the … Read more
In the C-plane, the NAS functional block is used for network attachment, authentication, setting up bearers, and mobility management. All NAS messages are ciphered and integrity protected by the MMEand UE. The radio resource control (RRC) layer in the eNB makes handover decisions based on neighbor cell measurements reported by the UE, performs paging of … Read more
One of the advantages of using LTE TDD is that it is possible to dynamically change the up and downlink balance and characteristics to meet the load conditions. In order that this can be achieved in an ordered fashion, a total of seven up / downlink configurations have been set within the LTE standards, in … Read more
In FDD, the DL and UL Radio Frames (RFs) are not on the same carrier. The RF frame is called Type 1 by the 3GPP. The RF length is 10 ms. The radio frame is made up of 10 sub-frames of 1 ms. Each sub-frame is made up of 2 slots of 0.5ms. For FDD, … Read more
How Many OFDMA Parameter for LTE? Which is OFDMA Parameter for LTE ? The width of a Sub-carrier is 15 kHz whatever the bandwidth The bandwidths are: 1.4, 3, 5, 10, 15 and 20 MHz Note that in LA1.1, only 5, 10 MHz are implemented The symbol duration is always the same whatever the bandwidth … Read more
what is main Difference between DL and UL in LTE ? OFDMA Advantages Robust against narrow-band co-channel interference Robust against Intersymbol interference (ISI) and fading High spectral efficiency Efficient implementation using FFT Drawbacks High Peak-to-Average Power Ratio The power limitation is more problematic in UL than in DL Signal with high PAPR will limit the … Read more
How OFDMA Transmitter in LTE ? In the downlink, OFDM is selected to efficiently meet E-UTRA performance requirements. With OFDM, it is straightforward to exploit frequency selectivity of the multi-path channel with lowcomplexity receivers. This allows frequency selective in addition to frequency diverse scheduling and one cell reuse of available bandwidth. Furthermore, due to its … Read more
In FDM, the sub-carriers are separated in the frequency domain to avoid interference between the sub-channels It results in a loss of spectrum efficiency because the frequency guard band can not be used to send data. The OFDM allows one to remove the frequency guard band. Benefit: There are more sub-carriers, so more symbols … Read more
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
The system designer will need to determine the specific RF link budget parameters to be used when designing the system. The following figure shows the typical gains and losses that are encountered in the RF path. An RF link budget must be determined for each sector of each site. The RF link budget for … Read more