| 摘要 |
A single transducer digital communication receiver is described which is capable of extracting the data bits of at least one desired signal in the presence of interfering signals of similar type. The present invention also seeks to provide a communication system in which overlapping transmissions are tolerated and allowed. The present invention describes a design for a digital communication system, according to a specific frequency plan, which includes an appropriate digital demodulator that extracts the data bits of the desired signal(s) in the presence of closely spaced signals. The present invention enables reduced channel spacing in digital communication systems and thereby increases the system capacity (i.e. the number of users per bandwidth unit) without incurring any significant loss in system performance (e.g. power margins, BER, and channel availability). It also allows a reduced power margin that is required to maintain a pre-specified performance level without sacrificing system capacity. These two factors, power margin and system capacity, play a central role in the design and construction of state-of-the-art digital communication systems which seek to pack more users on the same frequency band without incurring significant power loss. Thus, the present invention also provides a method and apparatus for upgrading existing systems such as a cellular system for mobile wireless communications that is based on the IS-54 or the GSM standard. |
