Abstract: A hard handoff method between asynchronous CDMA (code division multiple access) system and synchronous CDMA system is provided. A hard handoff method between asynchronous CDMA (code division multiple access) system and synchronous CDMA system in accordance with an embodiment of the present invention includes following steps. First step is to transmit asynchronous CDMA channels from synchronous CDMA base stations with a purpose of synchronizing handoff time at synchronous CDMA base station and code used at synchronous CDMA base station. The transmission is done by a mobile terminal that is in communication with an asynchronous CDMA base station. The transmission is a part of handoff process and the mobile terminal performs hard handoff to synchronous CDMA base station. Second step is to report measured result to the asynchronous CDMA base station on the basis of intensity of asynchronous CDMA pilot channel received from an adjacent synchronous CDMA base station. The reporting is done by the mobile terminal.

Abstract: An image compression method is provided which uses a wavelet transform technique to generate transform coefficients relating to an input image. Furthermore, the method generates and encodes an efficient tree structure of the transform coefficients by performing the following steps. First, transform coefficients are obtained by transforming an input image in accordance with the wavelet transforming technique. Then, a quantizing interval which minimizes quantization errors is determined for a predetermined step size and is determined according to statistical characteristics of the input image. Then, a simple tree structure is generated based on the transform coefficients, and such tree structure is modified by using statistical characteristics of the transform coefficients to produce a monotonically decreasing tree structure. The resultant tree structure is modified by limiting a maximum height difference between parent nodes and child nodes of the tree structure to produce the tree list.