| Summary: | 碩士 === 國立交通大學 === 資訊科學學系 === 84 === While ATM (Asynchronous Transfer Mode) serves as the backbone of
our NII (National Information Infrastructure), the
prevailing cable TV networks may serve as the NII
community networks that span the infrastructure into the
homes. However, in order to support these services to the
residential users, the community cable TV networks have to
be redesigned to support 2-way interactive communication.
In this work, we propose PCUP (Pipelined Cyclic Upstream
Protocol) as the upstream MAC (Medium Access Control)
protocol for HFC (Hybrid Fiber Coax) community access
network. PCUP is designed with the intention of pipelining
the upstream channel. This is achieved by proper station
positioning, which measures the station propagation offset
from the headend, and transmission scheduling, which assigns
each station the transmission starting time and duration in
a cycle. By taking into account the propagation offsets and the
transmission times, transmitted cells can appear back-to-back,
i.e. pipelined, at the headend. Since only the active stations
are scheduled to transmit in a cycle, a membership control
mechanism, which runs a contention-based tree walk algorithm,
is executed periodically to allow the stations to join or
leave.
We evaluate the behavior of our protocol through simulations to
show the effectiveness with respect to loss ratio,
throughput, delay, and setup latency. Comparisons with
R-ALOHA (Reservation Slotted ALOHA) and CSMA/CD are also
made. The results confirm PCUP's excellent performance.
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