Carrier Ethernet Services over WiMAX
As stated previously, the early development of the IEEE 802.16 standard was driven
by the objective to serve the needs of carriers. Therefore, much of the effort was on developing
the technology to satisfy the needs of the carriers. In this section, we discuss
how it fares in some of the carrier-centric attributes.
Failure Resiliency One of the key necessities for failure resiliency of a communication
protocol is the robustness of its PHY protocol. WiMAX defines very resilient PHY protocols.
All PHY protocols define an adaptive modulation scheme that allows for transmission
methods to be changed as the channel characteristics of the physical medium
changes. PHYs also allow for adaptive FEC algorithms, which provide an added level
of data transmission resiliency. In addition to the robustness provided by the PHY,
WiMAX also adds to the resiliency by allowing for retransmission (ARQ and H-ARQ)
on a per-connection basis.
Scalability It is often the case that limitation of a shared medium is its scalability.
Examples are some variants of Ethernet and WiFi, which are not very scalable because
of their contention-based MAC protocol.
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