QoS in IEEE 802.16-2009
QoS Performance Measures
The performance level of a connection is normally expressed in terms of its throughput, delay, jitter, priority and packet loss. However, the standard specifies another set of parameters to be used in setting up and maintaining a connection. In the following, the mapping between these two sets of parameters is detailed.
- Maximum sustained traffic rate: This is the peak information rate expressed in bits per second to which, the users' traffic shall on average be policed to conform to. However, this parameter only specifies a traffic bound, not a guarantee that the rate is actually available. It should also be mentioned that the standard does not specify any traffic policing mechanism.
- Maximum traffic burst: Is the maximum burst size accommodated for a particular service measured in bits. It is also the maximum continuous burst accommodated by the system for a service if this service is not currently using any of its allocated resources. The maximum sustained traffic rate and the maximum traffic burst are jointly identified by a six-bit code word. The standard documents define twenty three different levels for the maximum traffic burst and maximum sustained traffic rate are defined.
- Minimum reserved traffic rate: This last parameter represents the minimum rate reserved for a service flow measured in bits per second. A connection mapped to a certain superframe may request a data rate up to its minimum reserved traffic rate ...