Small cells sit alternately on either side of the street. Each has a 28 GHz mmWave link to the moving handset. Path loss follows the free-space 3GPP formula:
FSPL(dB) = 32.4 + 20·log10(f_GHz) + 20·log10(d_m)
RSRP = P_tx − FSPL − L_block (L_block ≈ 25 dB if a body/vehicle blocks the line of sight)
SINR ≈ 10^((RSRP − N0)/10), N0 = −95 dBm noise floor
Throughput = BW·log2(1 + SINR), BW = 100 MHz
Because mmWave range is short and easily blocked, the phone must switch cells far more often than on 4G. The handover uses the real 3GPP A3 event: a neighbour must beat the serving cell's RSRP by the hysteresis margin continuously for the time-to-trigger window before the switch fires (this debounce stops rapid "ping-pong" handovers from noise). Every handover briefly interrupts the link — count and interruption time both feed the outage stat.
- Cell spacing — denser small cells raise average RSRP but trigger more handovers.
- Blockers — pedestrians/vehicles crossing the line of sight add ~25 dB of loss, which can push RSRP below the −100 dBm outage floor even with a nearby cell.
- Hysteresis / time-to-trigger — larger values cut ping-pong handovers but let the phone linger on a fading cell longer, hurting throughput.
This is the same trade-off 5G mmWave network planners tune between capacity (many small cells), mobility robustness (handover parameters) and blockage sensitivity — the reason mmWave 5G is deployed as dense urban "hot zones" rather than wide-area coverage.