| 摘要 |
A preamble generating apparatus used for synchronization of a reception apparatus in an orthogonal frequency division multiplexing system and generating a preamble to be added to a beginning of data at a time of communication, receives preamble length identifying information and position specifying information, and generates a plurality of elements constituting a preamble according to a predetermined sequence based on those information. The preamble generating apparatus creates a preamble model, and generates a plurality of preambles by setting the generated elements at positions of elements in element deciding information included in the preamble model, the positions indicating elements in the preamble model which are to be used in data communication. The preamble generating apparatus calculates PAPRs respectively corresponding to the plurality of preambles, and compares the PAPRs of the preambles with one another to decide the preamble corresponding to a minimum PAPR as a preamble to be used in communication. |
| 主权项 |
1. A preamble generating apparatus used for synchronization of a reception apparatus in an orthogonal frequency division multiplexing system and generating a preamble to be added to a beginning of communication data at a time of communication, comprising:
a reception unit that receives preamble setting information including preamble length identifying information indicating a length of the preamble requested to be generated, guard position identifying information indicating a position of an element constituting a guard interval in the preamble, and center position identifying information indicating an element in approximately a center of the preamble; a preamble-elements generating unit that generates a plurality of elements constituting the preamble according to a predetermined sequence based on the preamble length identifying information received by the reception unit, wherein the preamble-elements generating unit performs the following:
if (1) the length of the preamble indicated by the preamble length identifying information is a power of two and (2) a square root of a value obtained by dividing the length of the preamble by two is an integer, creating elements comprising CAZAC sequences having a length equal to a value obtained by dividing the length of the preamble by two based on a Frank-Zadoff sequence;if (1) the length of the preamble indicated by the preamble length identifying information is a power of two and (2) a square root of the value obtained by dividing the length of the preamble by two is not an integer, creating two elements comprising CAZAC sequences each having a length equal to a half of the value obtained by dividing the length of the preamble by two based on the Frank-Zadoff sequence; orif the length of the preamble indicated by the preamble length identifying information is not a power of two, creating elements comprising a shortest CAZAC sequence that satisfies a length equal to or greater than a value obtained by (i) subtracting, from the length of the preamble, a length of the guard interval and a length of the element in approximately a center of the preamble, wherein the length of the element in approximately the center of the preamble is 1, and (ii) dividing the value obtained by (i) by two; a preamble-model creating unit that creates a preamble model including position information indicating a position of an element constituting the preamble and element deciding information indicating whether the element corresponding to the position is to be used in data communication, based on the preamble length identifying information, the guard position identifying information and the center position identifying information received by the reception unit; a preamble generating unit that generates a plurality of preambles by setting the elements generated by the preamble-elements generating unit at positions of the elements to be used in the data communication in the preamble model created by the preamble-model creating unit; a Peak-to-Average-Power Ratio (PAPR) calculator that calculates PAPRs respectively corresponding to the plurality of preambles generated by the preamble generating unit; and a preamble deciding unit that compares the PAPRs of the preambles calculated by the PAPR calculator with one another to decide that the preamble corresponding to a minimum PAPR is used in communication.
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