Hongyan

Expert Opinion

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

    Physical Hybrid-ARQ Indicator Channel (PHICH)

    • 3 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

    PDCCH Blind Detection

    • 1 Comments
    We discussed how PDCCHs are constructed from the CCEs in the control region of a subframe. Next, let's look at the PDCCH detection procedure; in other words, how a UE searches for the DCIs intended for it. The UE searches...
  • 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

    Cell Size Configuration in RACH (II) – Cyclic Shift

    • 1 Comments
    We have discussed the preamble format configuration vs. the maximum cell radius during the random access procedure. For example, Preamble Format 0 supports a maximum cell radius of 14.5 km. Another random access parameter that...
  • Hongyan

    Cell Size Configuration in Random Access Procedure (I) - Preamble Format

    • 2 Comments
    When we talk about the cell size, we usually think of RF coverage first. The cell radius is also related to the parameter configuration for the random access procedure, such as the preamble format and cyclic shift. Let's...
  • 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...