| according to GSM 05.02: |
| |
| general parameters from CCCH: |
| * CA cell allocation of ARFCN's (System Information / BCCH) |
| * FN: TDMA frame number (t1,t2,t3') in SCH |
| |
| specific parameters from channel assignment: |
| * MA: mobile allocation, defines set of ARFCN's, up to 64 |
| * MAIO: index |
| * HSN: hopping sequence generator number (0..64) |
| |
| |
| hopping sequence generation (6.2.3): |
| |
| u_int8_t rntable[114] = { |
| 48, 98, 63, 1, 36, 95, 78, 102, 94, 73, |
| 0, 64, 25, 81, 76, 59, 124, 23, 104, 100, |
| 101, 47, 118, 85, 18, 56, 96, 86, 54, 2, |
| 80, 34, 127, 13, 6, 89, 57, 103, 12, 74, |
| 55, 111, 75, 38, 109, 71, 112, 29, 11, 88, |
| 87, 19, 3, 68, 110, 26, 33, 31, 8, 45, |
| 82, 58, 40, 107, 32, 5, 106, 92, 62, 67, |
| 77, 108, 122, 37, 60, 66, 121, 42, 51, 126, |
| 117, 114, 4, 90, 43, 52, 53, 113, 120, 72, |
| 16, 49, 7, 79, 119, 61, 22, 84, 9, 97, |
| 125, 99, 17, 123 |
| }; |
| |
| /* mai=0 represents lowest ARFCN in the MA */ |
| |
| |
| u_int8_t hopping_mai(u_int8_t hsn, u_int32_t fn, u_int8_t maio, |
| u_int8_t t1, u_int8_t t2, u_int8_t t3_) |
| { |
| u_int8_t mai; |
| |
| if (hsn == 0) /* cyclic hopping */ |
| mai = (fn + maio) % n; |
| else { |
| u_int32_t m, m_, t_, s; |
| |
| m = t2 + rntable[(hsn xor (t1 % 64)) + t3]; |
| m_ = m % (2^NBIN); |
| t_ = t3 % (2^NBIN); |
| if (m_ < n then) |
| s = m_; |
| else |
| s = (m_ + t_) % n; |
| mai = (s + maio) % n; |
| } |
| |
| return mai; |
| } |
| |