Hongyan

Expert Opinion

Expert Opinion
Short LTE articles and opinions by our team of Subject Matter Experts (SMEs)
  • Hongyan

    How to calculate peak data rate in LTE?

    • 12 Comments
    You may hear it many times that the peak data rate of LTE is about 300Mbps? How is the number calculated? What are the assumptions behind? Let's estimate it in a simple way. Assume 20 MHz channel bandwidth, normal CP, 4x4...
  • Hongyan

    PDCCH Construction

    • 9 Comments
    The PDCCH (Physical Downlink Control Channel) in LTE carries UE-specific scheduling assignments for Downlink (DL) resource allocation, Uplink (UL) grants, PRACH (Physical Random Access Channel) responses, UL power control commands...
  • Hongyan

    Physical Hybrid-ARQ Indicator Channel (PHICH)

    • 4 Comments
    The Physical Hybrid-ARQ Indicator Channel (PHICH) in the downlink carries Hybrid ARQ (HARQ) acknowledgements (ACK/NACK) for uplink data transfers. PHICHs are located in the first OFDM symbol of each subframe. (Note that our...
  • Hongyan

    UE measurement in LTE

    • 4 Comments
    In cellular networks, when a mobile moves from cell to cell and performs cell selection/reselection and handover, it has to measure the signal strength/quality of the neighbor cells. We know that in UMTS, a UE measures RSSI, CPICH...
  • Hongyan

    PDCCH Dimensioning

    • 3 Comments
    We have discussed PCFICH resource mapping, PHICH resource mapping, and PDCCH construction. Now we are ready to look at PDCCH dimensioning. Since the PDCCH is constructed from Control Channel Elements (CCEs) with an aggregation...
  • Hongyan

    CQI Reporting in LTE

    • 2 Comments
    CQI (Channel Quality Indication) report is an important element of LTE and has significant impact on the system performance. There are two types of CQI report in LTE: periodic and aperiodic. The periodic CQI report is ...
  • Hongyan

    LTE System Information: Part 3

    • 2 Comments
    The transmission time and periodicity for the MIB and SIB1 are fixed by the specifications. A UE knows exactly when to listen for them. The transmission time and periodicities of other SIBs are configurable and scheduled by...