Showing posts from November, 2019

Carrier Aggregation Part-2

Home                 LTE                NB-IoT            5G(NR-NSA)   What is LTE aggregated carriers? The LTE aggregated carriers indicates a combination of maximum PRB and maximum number of CCs ( component carrier) . In R10 and R11 three classes are defined: Class A: PRB ≤ 100,  maximum number of CC = 1 Class B:  PRB ≤ 100, maximum   number of CC = 2 Class C: 100< Nrb ≤ 200, maximum number of CC = 2 Class D: 200< Nrb ≤ 300, maximum number of CC = 3      How many CC support in Bandwidth Class A? one CC How many CC support in Bandwidth Class B? 2 CC How many CC support in Bandwidth Class C? 2 CC What is CA configuration ? The CA configuration indicates a combination of EUTRA operating bands and CA bandwidth class.  Let's take some example: For instance the configuration CA_7C indicates intra band contiguous carrier aggregation on EUTRA operating band 7 and CA bandwidth class C. (Two contiguous CC in frequency band 7 and transmissi

Carrier Aggregation Part-1

Home                 LTE                NB-IoT            5G(NR-NSA)   Hello readers today we are going to learn about carrier aggregation. To make the topic more interesting and easier to learn I have written this article in the question answer format. So first thing first, When was CA introduced? It has been defined for the first time in 3GPP release 10(it’s also called LTE Advance features). What is Carrier Aggregation and why it is needed? CA is a technology to combine two or more carriers into one data channel to enhance the data capacity. It is also possible to combine same or different frequency bands. CA is used in LTE-Advanced in order to increase the bandwidth, and thereby increase the bit rate. Since it is important to keep backward compatibility with R8 and R9 UEs the aggregation is based on R8/R9 carriers. CA can be used for both Time division duplex (TDD) as well as Frequency division duplex (FDD). OR What is goal of CA? The goal

Soft Handover vs Hard Handover

Home                 LTE                NB-IoT            5G(NR-NSA) Now before we move to other things like measurements in handover, handover decision, handover procedure, handover interruption time, and mobility robustness optimization, let us take a look into difference between soft handover and hard handover. Soft Handover Hard Handover The handover in which radio links are added and removed in a way that MS always keeps at least one radio link to the UTRAN is known as soft handover. The handover in which all the old radio links in MS are removed before the new radio links are established is known as hard handover. This can also be simplified as make before break This can also be simplified as break before make As call drop rate is lower this handover is used to lower the rate of call drop. In this case higher rates of call drops are found Why soft handover is not included

Handover Basics

Home                 LTE                NB-IoT            5G(NR-NSA) Handover Basics: Before starting handover in detail let us take an overview of LTE handover. We all are aware that one of the greatest advantages of a mobile device or wireless device is that one can travel (user) while using the service on it. Because of this feature many users has outvoted the use of wired devices.   This feature of mobility has allowed users to comfortably use their mobile devices at any place, anywhere, anytime, weather at home or on the go. Mobile (cell phone) users can use services while on the go due to the fact that mobile networks provide handovers. So this feature (handover) helps UE (user equipment) to switch from one cell or base station (eNB- in the case of LTE) (gNB- in the Case of NR) to other cell or base station without losing any information and communicate with the network without interruption. Thus handover ensures that user is served seamlessly no matter which c

Types of BWP

Home                LTE               NB-IoT            5G(NR-NSA) In the previous section we learned about BWP and its configuration. Now in this document we will learn more on BWP types and switching. Now to begin with we know that carrier of one BWP is divided into several BWPs and each BWP has a continuous PRB(physical resource block). Some BWPs have SSB and associated RMSI while some BWPs have SSB but no associated RMSI and some BWPs don’t even have SSB. Now, How many types of BWPs a network can configure? Network can configure three different BWP – Initial BWP and two UE specific types, namely first active BWP and default BWP.  Below IEs are used for BWP configuration: (The BWP is split into Downlink and Uplink parameters and into common and dedicated parameters.) 1) DL BWP: 2) UL BWP: Let's talk about BWP types: 1) Initial BWP: When a device enters from idle mode to the connected state it obtains the information from