A wireless radio network may consist of many mobile subscriber units (“MSUs”) all competing for bandwidth resources that are offered in their service area. In addition, fixed network equipment (“FNE”) that serves the MSUs may offer different levels of service in the form of channels of differing bandwidth capabilities. Due to the different levels of service, radio resource management is necessary.
Several techniques have been used to perform radio resource management. One is for the FNE to advertise to the MSUs information about each channel. The MSUs can then choose to move to a new channel if the channel that they are using is no longer satisfactory due to the signal quality or channel loading. This technique may be referred to as “autonomous movement” because the MSUs move to a new channel without informing the FNE prior to registration.
There are several disadvantages with the autonomous movement technique. One disadvantage is that the MSUs move without the knowledge of what the other MSUs are doing, so it is possible for many MSUs to move all at once; if they all make their decision to move based on the same advertised data, they could all move to the same channel, causing that channel to become overloaded. Another disadvantage to the autonomous movement technique is that the MSUs move based on advertised data, which may be out of date when they decide to move. Yet another disadvantage to the autonomous movement technique is that the MSUs move without first informing the FNE, so there is a short period of time when the FNE has outdated information about what channel the particular MSU is on. Yet still another disadvantage to the autonomous movement technique is that the amount of data that must be advertised for an MSU to make a “good” decision to move to another channel can be excessive, thus using up too much of the available bandwidth.
Another technique to perform radio resource management is that the FNE always controls what channel the MSU is on. If a MSU wants to use a channel, it requests a channel from the FNE. The MSU may request a channel before every transmission, or only when it is unable to transfer data on the current channel. In addition, the FNE may attempt to move the MSUs in order to keep an even load on the channels.
There are also several disadvantages to this technique. One disadvantage is that the FNE does not know the signal quality of each bandwidth group, or each individual channel, so it may move the MSU to a channel having a poor signal quality. Another disadvantage is that the FNE does not know when a MSU is going to need bandwidth resources, so it may move a MSU unnecessarily. Yet another disadvantage is that overhead signaling is required, which can slow down access to the network by the MSU.
Moreover, the autonomous movement technique and the radio resource management technique require certain signal quality measurements to be made by the MSUs on a plurality of channels. An issue with these measurements is that they can be intrusive to the normal operation of the MSU.
Thus, there exists a need for efficiently assigning the MSUs to channels such that the bandwidth resources of the FNE are used effectively, and a need for effective channel quality measurements so that they are not as intrusive to the normal operation of the MSU.