Abstract: Robust Header Compression (RoHC) compressors and decompressors are provided. A RoHC compressor includes a memory and a processor. The memory stores multiple contexts and multiple codes or program instructions. The processor executes the codes or the program instructions to perform the following steps: receiving a header flow; freeing at least one of the contexts when free space of the memory is insufficient; compressing the header flow; and transmitting the compressed header flow.

Abstract: Robust Header Compression (RoHC) compressors and decompressors are provided. A RoHC compressor includes a memory and a processor. The memory stores multiple contexts and multiple codes or program instructions. The processor executes the codes or the program instructions to perform the following steps: receiving a header flow; freeing at least one of the contexts when free space of the memory is insufficient; compressing the header flow; and transmitting the compressed header flow.

Abstract: A method for performing mode transition of compression operation in a transmission device, and an associated transmission device, are provided. The compression operation includes a plurality of modes. The method includes: determining whether a module within the transmission device transforms a mode within the plurality of modes into another mode within the plurality of modes to transmit a set of context data; and when the module transforms the mode into said other mode to transmit the set of context data, transmitting other sets of context data that also belong to the module in said other mode, wherein the transmission device includes a compressor and a decompressor, and the module represents the compressor or the decompressor.