4G LTE

WKT UE will receive downlink data over PDCCH. So UE has to monitor PDCCH everytime to check if there is any downlink data available. By doing…

Before we learn about Logical Channel Prioritization (LCP), we need to learn about channel starvation. Channel Starvation: Before LCP, every…

dlInformationTransfer Direction: eNB => UE Signalling Radio Bearer: SRB2 or SRB1 RLC Mode: AM Logical Channel: DCCH Transport Channel:…

BSR is a MAC UpLink control element. Truncated BSR LCID value is “11100” in binary and 28 in decimal Short BSR LCID value is…

Below is the MAC PDU structure: From the above image we can see that, one MAC PDU has 2 parts 1. MAC Header 2. MAC Payload. Mac Header can…

Power Headroom Report (PHR) is a MAC Uplink Control Element. LCID value is “11010” in binary and 26 in decimal * Every UE will…

NAS layer : Non-Access Stratum: This is used to communicate control plane information between UE and MME. NAS layer protocols functions are to…

In this chapter we shall see the keys exchanged between different procedures. Below security flows is a smaller part in LTE Attach Request. To…

  Step 1: UE will read MIB and SIB from network to synchronize with the network. Step 2: UE will send Random Access Preamble (RAP)…

Detach Request can be initiated from UE or by the Network. We shall learn both types of detach request in this chapter. Below are the messages…