This paper explores the growth in mobile data, and examine how this growth impacts QoE by placing heavy strains on wireless network resources. The paper reviews how wireless networks are evolving from primarily voice-only services to converged voice,
video, and data traffic, and how operators can use the emerging 3GPP standards for QoS and policy management to ease network congestion, provide higher service quality, and create a framework for new business models. Finally, we will discuss techniques to validate service quality for mobile broadband and explore a voice over LTE (VoLTE) QoS-validation use case from a tier-one operator.
Monthly Archives: June 2012
C++ Coding Style Guide from Google
Google has a comprehensive C++ coding standard that covers the following areas:
- Header files
- Scoping
- Classes
- Naming
- Commenting
- Formatting
Google Python Class: Utilities – OS and Commands
The next lecture in the series. This lecture covers how Python can be used for shell scripting and interfacing with the OS.
Revise what you learnt:
OFDM tutorial
LTE moves away from CDMA to OFDM – Orthogonal Frequency Division Multiplexing. This article provides an excellent introduction to OFDM.
LTE User Equipment Categories
LTE supports five categories of terminals. The details of the terminal types in uplink and downlink are detailed below:
LTE UE Category: Downlink Physical Layer Parameters
| UE Category | Maximum number of DL-SCH transport block bits received within a TTI | Maximum number of bits of a DL-SCH transport block received within a TTI | Total number of soft channel bits | Maximum number of supported layers for spatial multiplexing in Downlink | Maximum bit rate in Downlink (Mbps) |
| Category 1 | 10296 | 10296 | 250368 | 1 | 10 |
| Category 2 | 51024 | 51024 | 1237248 | 2 | 50 |
| Category 3 | 102048 | 75376 | 1237248 | 2 | 75 |
| Category 4 | 150752 | 75376 | 1827072 | 2 | 75 |
| Category 5 | 299552 | 149776 | 3667200 | 4 | 150 |
LTE UE Category: Downlink Physical Layer Parameters
| UE Category | Maximum number of bits of an UL-SCH transport block transmitted within a TTI | Support for 64QAM in Uplink | Maximum bit rate in Uplink (Mbps) |
| Category 1 | 5160 | No | 5 |
| Category 2 | 25456 | No | 25 |
| Category 3 | 51024 | No | 50 |
| Category 4 | 51024 | No | 50 |
| Category 5 | 75376 | Yes | 75 |
Refer to 3GPP 36.306 for other UE attributes.
IMS registration sequence diagram
This sequence diagram details the message interactions involved in IMS registration. IMS registration from a visited IMS network is covered. The interactions covered are:
- Terminal attaching to the GPRS Network.
- Terminal activates a PDP context.
- An unauthenticated IMS registration is attempted.
- IPSec security association is established between the User terminal and the P-CSCF.
- Finally the terminal performs an IPSec protected registration that completes the authentication of the network and the terminal.
Google Python Class: Regular Expressions
Revise: Python regular expressions

