mirror of https://gerrit.osmocom.org/osmo-tetra
24 lines
702 B
C
24 lines
702 B
C
#ifndef TETRA_SCRAMB_H
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#define TETRA_SCRAMB_H
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/* TETRA scrambling according to Section 8.2.5 of EN 300 392-2 V3.2.1 */
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/* This converts from type-4 to type-5 bits (and vice versa) */
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#include <stdint.h>
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/* Section 8.2.5.2:
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* For scrambling of BSCH, all bits e(1) to e(30) shall equal to zero
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* p(k) = e(1-k) for k = -29, ... 0
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* p(k) = 1 for k = -31, -30
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*/
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#define SCRAMB_INIT 3
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uint32_t tetra_scramb_get_init(uint16_t mcc, uint16_t mnc, uint8_t colour);
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int tetra_scramb_get_bits(uint32_t lfsr_init, uint8_t *out, int len);
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/* XOR the bitstring at 'out/len' using the TETRA scrambling LFSR */
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int tetra_scramb_bits(uint32_t lfsr_init, uint8_t *out, int len);
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#endif /* TETRA_SCRAMB_H */
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