The impact of the ATM concept on video coding

A New Call Admission Control Mechanism for Multimedia Traffic over Next-Generation Wireless Cellular Networks

“…As explained in Section 1, our scheme generally falls within the category of the probabilistic service [8]. However, the regular use in this type of scheme of the "equivalent bandwidth" method for estimating the aggregate bandwidth (for example, as in [10], [11], [12], [13], [14], [15], [16], [32], and [33]), which will be needed by a superposition of sources, is a quite conservative approach, as it has been shown in the literature. It only provides an approximate formula, which generally significantly overestimates the sources' actual bandwidth requirements.…”

“…This results in good QoS for all admitted users (customers), but as in the case of the guaranteed service, a significant portion of the wireless channel bandwidth is again left unused. More specifically, in [10], the equivalent bandwidth of a set of flows is defined as the bandwidth CðÞ, which is such that the stationary bandwidth requirement of the set of flows exceeds this value, with a probability of at most , where is the packet loss rate. However, in the case of the absence of a very accurate statistical model for each individual flow, the use of the effective bandwidth allotment leads to a significant overestimation of the sources' actual bandwidth requirements and, therefore, to a conservative CAC scheme, which fails to efficiently use all of the available bandwidth, as shown in [11], [12], [13], [14], and [15].…”

“…The standard method of implementation for this service type is that each source is allotted an "equivalent bandwidth" (also called "effective bandwidth"), which is larger than its average rate but less than its peak rate. In most cases, the equivalent bandwidth is computed based on a statistical model [9] or a fluid flow approximation of traffic [10], [11]. 3.…”

Call-Admission-Control and Traffic- Policing Mechanisms for the Transmission of Videoconference Traffic From MPEG-4 and H.263 Video Coders in Wireless ATM Networks

“…Our simulation results have shown that the method presented in [11] for calculating the equivalent bandwidth of the superposition of the movies greatly overestimates the actual bandwidth requirements. This "problem" is not restricted to just this method, but has been encountered in other methods as well (e.g., the authors in [12] comment on their own method as overestimating the actual bandwidth requirements).…”

Call Admission Control for wireless videoconference traffic based on the users' willingness to pay

“…We further investigate our mechanism's performance in the results presented in Figure 1, where we present both the estimation provided by the DAR model and the actual bandwidth usage from our CAC mechanism; we also indicatively present the estimation provided by the use of the equivalent bandwidth approach from [6]. All the above are presented versus the normalized real system utilization; this indicates the actual traffic load generated by the traces, normalized to the channel capacity, e.g., a traffic load equal to 40% represents 40% of the 20 Mbps downlink capacity, i.e., 8 Mbps system throughput (these loads have been created for each of the five scenarios under study, and the results presented are the average over all the conducted simulations).…”