How to Calculate LTE Data Rate – Downlink Throughput

This tutorial explains how LTE downlink maximum throughput is determined. This is a simple and straightforward formula for data rate calculation.

The maximum data rate depends on channel bandwidth. As LTE uses different channel bandwidths both for FDD and TDD.

Let’s take the example for LTE using FDD, where channel bandwidth can be 5 MHz, 10 MHz and 20 MHz. In LTE release 8 there is no carrier aggregation, so let’s just consider simple cases.
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IMS Multimedia Emergency Session (MES) – Emergency calls in the IM CN subsystem

A few weeks ago I was looking into an issue related to E911 or Emergency call over the IMS network. Though it appears as most of the concepts related to emergency calls are still same in IMS as compared to legacy systems, such as 3G and GSM, there are many new things are added for IMS.

Both in UMTS and GSM and other CS based systems emergency call was often referred to speech calls, but the IP Multimedia Subsystem(IMS) supports different other types of media along with speech calls. When other media types are used during an emergency session, it is referred as IMS Multimedia Emergency Session (MES).

As usual whenever the user calls an emergency number by default the call is routed to the emergency service.

Let’s find it out what different media types an IMS UE supports during a E911 session towards IP PSAPs (emergency response centre).

  • Real time video both simplex and fullduplex
  • Text-messaging (Similar to SMS)
  • File transfer
  • Video clip sharing, picture sharing, audio clip sharing
  • Voice
  • GTT

IMS Multimedia Emergency Session Other Media Continue reading

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IPhone 6 Comes with Qualcomm’s MDM9625 LTE Modem

iphone6-qualcomm-MDM9625
According to latest reports Apple iPhone 6 will feature a Qualcomm MDM9625 LTE modem. Though the wireless modem is not the best from Qualcomm and not the latest, still it features some of the best technology options.

Here are some of the things you should expect from iPhone 6 modem.

Qualcomm MDM9625

Qualcomm MDM9625 features HSPA+ Release 10 and the next-generation of the LTE mobile broadband standard, LTE Advanced in the same chip. Apart from that MDM9625 is a category 4 LTE modem and supports Carrier Aggregation. This improves the downlink data rates up to 150 Mbps. Implemented in a 28nm manufacturing process, the chipsets will feature significant improvements in performance and power consumption from previous generations and provide support for multiple mobile broadband technologies to deliver a best-in-class mobile broadband experience.

Here are the key features of Qualcomm MDM9625 modem which will power Apple iPhone 6:

  • 28nm chipset design
  • Supports LTE Advanced (LTE Release 10)
  • Supports HSPA+ Release 10 (including 84 Mbps dual carrier HSDPA)
  • Backward compatible with other standards, including EV-DO Advanced, TD-SCDMA and GSM.
  • Downlink throughput of 150 Mbps when using LTE Advanced

Here is a video which shows what Qualcomm MDM9625 can capable of:

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LTE MAC Layer – Medium Access Control

LTE User Plane and Control Plane
This tutorial describes the specific details of the LTE MAC layer or the Medium Access Control protocol. MAC is a radio network protocol which resides both in the UE and in the E-UTRAN. Also, it should be noted that MAC protocol is available for both User plane and also for the control plane.

RRC (Radio Resource Control) protocol is in control of the configuration of MAC that means RRC decides how MAC will behave. For example RRC tells MAC to configure a specific PDU size. Continue reading

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Hyper-dense small cells deployment for better coverage and throughput

UltraSON-Small-Cells-deployments
When the best data throughput of today becomes bad in couple of years and mobiles are used more as entertainment and file sharing purpose than voice call, we need new revolutions to achieve best data rate using existing technologies.

According to latest study by Qualcomm by 2017 two third of mobile traffic will be from video. There is also predictions that there will be 25 billion interconnected devices by 2020. So what is the solution to fix this data scarcity problem?

One of the solution is use many small cells which eventually works as WiFi hotspots. There may be unplanned deployments for both indoor and outdoor use.

Checkout this informative white paper from Qualcomm to understand the problem we are going to face soon and the use of hyper-dense small cells to solve data throughput issues.

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