Abstract: A communication system which has a plurality of mobile terminals and a base station, each of the mobile terminals and/or base station comprising a medium access control sub-layer, upper layers of the medium access control sub-layer, and a lower layer of the medium access control sub-layer, wherein the medium access control sub-layer is configured to perform self-basic functions in response to basic function execution requests or functions associated with the upper layers or lower layer in response to requests therefrom. According to the present invention, the communication system can provide a compatible multimedia communication service even if an originating terminal and a terminating terminal employ different communication manners, they are available from different manufacturers or they are operated by different communication service operators.

Abstract: A communication system which has a plurality of mobile terminals and a base station, each of the mobile terminals and/or base station comprising a medium access control sub-layer, upper layers of the medium access control sub-layer, and a lower layer of the medium access control sub-layer, wherein the medium access control sub-layer is configured to perform self-basic functions in response to basic function execution requests or functions associated with the upper layers or lower layer in response to requests therefrom. According to the present invention, the communication system can provide a compatible multimedia communication service even if an originating terminal and a terminating terminal employ different communication manners, they are available from different manufacturers or they are operated by different communication service operators.

Abstract: A communication system which has a plurality of mobile terminals and a base station, each of the mobile terminals and/or base station comprising a medium access control sub-layer, upper layers of the medium access control sub-layer, and a lower layer of the medium access control sub-layer, wherein the medium access control sub-layer is configured to perform self-basic functions in response to basic function execution requests or functions associated with the upper layers or lower layer in response to requests therefrom. According to the present invention, the communication system can provide a compatible multimedia communication service even if an originating terminal and a terminating terminal employ different communication manners, they are available from different manufacturers or they are operated by different communication service operators.

Abstract: An improved data writing density judging apparatus and method for a disc capable of judging a writing density of a disc by detecting an amount of cross talk or detecting a tracking error signal. Cross talk is detected when a disc track is scanned by a beam. A tracking error signal is detected when a pick-up member jumps a certain track while the pick-up member moves across a disc track. The improved apparatus and method computes a ratio between a minimum value and a maximum value of an envelope signal based on the detected amount of cross talk a writing density can be determined. The improved apparatus and method also converts a tracking error signal which is a high frequency analog signal into a digital signal that is used to compute a time required for a pick-up member to jump a certain track. Based on the computed time which is compared with a reference value, a writing density of a disk can also be determined.

Abstract: An improved data writing density judging apparatus and method for a disc capable of judging a writing density of a disc by detecting an amount of cross talk or detecting a tracking error signal. Cross talk is detected when a disc track is scanned by a beam. A tracking error signal is detected when a pick-up member jumps a certain track while the pick-up member moves across a disc track. The improved apparatus and method computes a ratio between a minimum value and a maximum value of an envelope signal based on the detected amount of cross talk a writing density can be determined. The improved apparatus and method also converts a tracking error signal which is a high frequency analog signal into a digital signal that is used to compute a time required for a pick-up member to jump a certain track. Based on the computed time which is compared with a reference value, a writing density of a disk can also be determined.