**2.3 Network Aware Differentiated Bandwidth Allocation Mechanism (nDBAM)**

Though eDBAM improves the throughput, the algorithm is indifferent to the current network conditions. Especially, if eDBAM method-1 is implemented, it could result in delays for regular and low-priority RTPS. Users might face jitter when they are viewing videos. This might not be desirable. nDBAM takes care of current network conditions before allocating bandwidth to the different service flows. The steps for nDBAM algorithm as given below.

**Step 1.** Users shall be allotted bandwidth as per one of the selected Seven methods of eDBAM.

BS keeps monitoring the network condition. BS could poll the SS to know their current queue length and the average queuing delays faced for each service flow. BS and SS can use the ranging mechanism to pass the information between them.


#### **2.3.1 Implementation**

BS does ranging at periodically with the SS. Ranging process is generally done to adjust the power levels and the clock skews. During the ranging process, BS can also request for the current queue state for the different service flows. As a part of ranging response (RNG-RSP) The SS can send the queue state to BS. The information is generally sent as a TLV (Type-Length-Value) header. A new header will be required to send the queue state information. Table 9 lists an example for the TLV.


Table 9. TLV header used to send Queue state.

BS receives the RNG-RSP from all the SS for each of their service class. BS then checks if the queuing delay is within the QoS limits for the service class. If not then it means that the eDBAM algorithm is introducing delay for regular and low-priority users. So, BS shifts from eDBAM to DBAM.
