telecom • networking • design

an EventHelix.com blog


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QoS and Policy Management in LTE

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.

LTE policy and charging control framework

LTE policy and charging control framework

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OFDM tutorial

LTE moves away from CDMA to OFDM – Orthogonal Frequency Division Multiplexing. This article provides an excellent introduction to OFDM.

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OFDM tutorial from complextoreal.com


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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.


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LTE and WiMax Tutorial

Detailed presentation that covers the following topics:

  • Fundamental constraints from the Shannon Limit
  • Multipath radio propagation
  • Time varying multi-path channel
  • Cellular systems and frequency reuse
  • 4G enabling technologies
    • OFDM/OFDMA
    • SC-FDMA
    • MIMO
    • Fast channel-dependent scheduling
    • Fractional frequency reuse
  • OFDM
    • Orthogonal sub-carriers
    • OFDM implementation using DFT
    • Cyclic Prefix
    • Frequency Domain Equalization
  • SC-FDMA
    • Subcarrier mapping
    • SC-FDMA is DFT precoded OFDMA
    • PAPR characteristics
  • MIMO
    • Spatial diversity
    • Spatial multiplexing
  • Channel dependent scheduling
    • Select channels based on users signal quality in the resource grid
  • LTE specifications
    • Network architecture
    • Frame structure
    • Resource grid
    • Bandwidth configuration
  • LTE physical channels
  • LTE transport channels
  • LTE logical channels
  • Downlink physical channel processing
  • Uplink physical channel processing
  • Random access
  • LTE Advanced
    • Channel aggregation
    • Enhanced MIMO
  • WiMax


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3GPP LTE Evolved Packet System & Application to Femtocells

The Evolved Packet System (EPS) comprises the Long-Term Evolution (LTE) specifications of the 3GPP mobile network standard, including evolved radio access network (E-UTRAN) and system architecture evolution (SAE). This talk provides an overview of the 3GPP mobile network evolution, including the following topics: from GSM over UMTS to LTE and LTE-Advanced: the roots of next generation mobile network standards; 3GPP standardization architecture: specification groups and their responsibilities; overview of the LTE/SAE system architecture; quality of service architecture; overview of E-UTRAN; outlook on LTE-Advanced and beyond; and, of course, femtocells in LTE.