step 413 if the generic mac header cid requires the piggyback the ms goes to step 415 in the case where transmission data exists for the generic mac header cid and bandwidth allocation is needed for the generic mac header cid by a piggyback it can be said that the generic mac header cid requires the piggyback in step 415 the ms sets the type lsb to 0 and the bwr to 1 in the generic mac header then the ms lends the piggyback area of the generic mac header cid to the cid selected in step 403 in step 417 the highest priority level of a service class with the same qos is given to the generic mac header cid for the next ul bandwidth allocation request in step 417 step 417 may be skipped depending on a system situation on the other hand if the generic mac header cid does not require the piggyback in step 413 the ms proceeds to step 419 in the case where there is no transmission data associated with the generic mac header cid and thus it is not necessary to issue a bandwidth allocation request for the generic mac header cid it can be said that the.