The paper proposes a vertical handoff algorithm based on differential pre-decision and improved utility-function method. This algorithm is relied on utility function to improve its two parameters, which are received s...
详细信息
The paper proposes a vertical handoff algorithm based on differential pre-decision and improved utility-function method. This algorithm is relied on utility function to improve its two parameters, which are received signal strength and bandwidth, by using their normalized values to determine the target network. Then, it enters judgment stage of vertical handoff, where introduce differential prediction algorithm that has good accuracy to further constraint the switching decision through taking a prediction of the RSS into account. The purpose is to reduce the impact of ping-pong effect and to obtain accurate handoff. The paper applies MATLAB software to gain the simulated analysis based on this algorithm, And compares the performance of this switching algorithm with utility function algorithm to demonstrate its priority. Simulation results shows that the proposed algorithm can significantly reduce the impact of the ping-pong effect and improve the switching efficiency and the system performance as well in heterogeneous network environments.
This study presents a fast intra-prediction algorithm for a high-profile H.264 encoder. First, a pre-decision algorithm is proposed to reject the impossible block size based on image variance. Then a fast 4x4 block pr...
详细信息
This study presents a fast intra-prediction algorithm for a high-profile H.264 encoder. First, a pre-decision algorithm is proposed to reject the impossible block size based on image variance. Then a fast 4x4 block prediction algorithm is proposed to select four possible modes from nine predicted modes based on the edge-filtering detection. With a hierarchical approach, the 8x8 block prediction is based on the result of the chosen 4x4 block mode. This approach selects only one to five modes of H.264 coding from nine prediction modes. Following the prediction of the 16x16 luminance block and 8x8 chrominance block is mapped by the result of the 8x8 luminance block by checking only one to two modes. The pre-decision algorithm, the fast 4x4, 8x8 and 16x16 block prediction algorithms can be combined to improve the coding speed. Simulations demonstrate that the proposed algorithm can save about 70% coding time at most for intra-frame coding in the H.264 system while increasing only about 1% bit-rate with a negligible peak signal-to-noise ratio drop.
暂无评论