Abstract: First data is repeatedly sent out by using various sorts of transfer speeds by a receiver; a preselected number of polarity information about the first data is sequentially compared with each other by a first incoincident number detector to detect a first incoincident number; a most likelihood pathmetric value is detected by Viterbi-decoding each of second data a most likelihood detector; the polarity information of the respective second data is compared with the polarity information of corresponding coded data by a second incoincident number detector to detect a second incoincident number; and the transfer speed of the transmission processing is predicted by a transfer speed predicting circuit based on the first incoincident number, the most likelihood pathmetric value, and the second incoincident number, acquired every transfer period.

Abstract: A receiving apparatus and a receiving method translates information of reception data, received by receiving means into a soft decision symbol with data translating means, translates a replacement information into the specific soft decision symbol which indicates that information has disappeared due to replacement to create first disappeared-information added data, decodes this through de-interleaving means and decoding means, and locates disappeared information a the replaced position without a translation table of the replaced position and/or an arithmetic circuit. In this way, disappearance treatment of the received data can be performed with a simple circuit configuration, and the resulting first disappearance-information added data can be decoded using known techniques.

Abstract: A viterbi decoder that performs viterbi decoding at a high speed with low power consumption using a memory such as a random access memory as a path selection information storage unit. Adder-comparator-selector (ACS) processing units 13a, 13b time-divisionally perform ACS processing for even and odd number states, respectively, based on the branch metrics from a branch metric computing unit 12 and the path metric of the previous period to produce the path selection information. Eight states of the path selection information storage are collected together by a temporary storage circuit 20 and sent to and written in a path selection information storage unit 15. In the path selection information storage unit 15, the past path selection information is read out during the time other than a write time for the path selection information.

Abstract: A Viterbi decoder for reducing the access times of the path metric memory, for lowering the power consumption, speeding up the Viterbi decoding. includes a branch metric operating unit 12, an adder, comparator, selector (ASC) operating unit 13a and 13b, a path metric memory 14a for the lower states, and a path metric memory 14b for the upper states. The ACS operating unit 13a performs the ACS operation about the even states on the branch metric from the branch metric operating unit 12 and the path metric at the previous time point. The ACS operating unit 13b performs the ACS operation about the odd states. These ACS operations are executed in a time-dividing manner. The path metrics from these ACS operating units 13a and 13b are written in the path metric memories 14a and 14b. The memory 14a or 14b stores as one storage unit the path metrics of the adjacent even and odd states.

Abstract: A cellular communication system includes a mobile station with a switch or button which, when actuated by the user, calls a predetermined party. In the case of an emergency, the user actuates this switch and automatically places a call to an emergency agency. The switch also actuates a system for automatically locating the mobile station by measuring distances from the mobile station to a plurality of fixed stations in the cellular communication system.

Abstract: A Viterbi decoder for decoding a convolution coded reception signal. The Viterbi decoding uses an algorithm for efficiently executing the maximum likelihood decoding using a convolution code by selecting a path locating at the minimum distance from a reception series between two paths which are joined. Since it is necessary to store a state metric of each state, after the state metric of the surviving path was calculated by ACS calculation, it is considered to normalize metrics. However, this results in a large circuit scale and a low processing speed. Therefore, in this invention, a maximum likelihood value of a present state metric is detected from a maximum likelihood branch metric pair before the ACS calculation and the preceding maximum likelihood state metric pair and metrics are normalized by using the maximum likelihood value.