Optimal frequency assignments of cycles and powers of cycles

  • Authors:
  • Hsun-Wen Chang;Hao-Wen Chen

  • Affiliations:
  • Department of Applied Mathematics, Tatung University, Taipei, Taiwan, ROC.;Department of Applied Mathematics, Tatung University, Taipei, Taiwan, ROC

  • Venue:
  • International Journal of Mobile Network Design and Innovation
  • Year:
  • 2006

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Abstract

To reduce the interfering among transmitters, any two 'close'transmitters, with distance no more than d2, mustreceive frequencies at least l2 apart, and any two 'veryclose' transmitters, with distance no more than d1, mustreceive channels at least l1 apart. Theassignment problem is to assign a frequency to each transmittersuch that total bandwidth of assigned frequencies can be minimised.In this paper, we present upper and lower bounds of the minimumbandwidth of cycles and powers of cycles. We also show thecorresponding assignment functions. And then we partially solve theassignment problem of cycles Cn and their powers suchas: (i) 3 ≤ n ≤ 2d1+1; (ii) 2d1 + 2≤ n ≤ 2d2 + 1, q1 ≠ 0 andl1 ≤ m1l2; (iii) 2d1+ 2 ≤ n ≤ 2d2 + 1, q1 ≡ 1(modm1) and l1 m1l2;(iv) 2d1 + 2 ≤ n ≤ 2d2 + 1,q1 = 0 and l1 ≥ (m1 +d1 − 1)l2 or l1 ≤(m1 − 1)l2; (v) n ≥ 2d2 +2 and l1 ≤ ⌊(d2 +⌊q2/m2⌋)/(d1 +1)⌋l2; and (vi) n ≥ 2d2 + 2,q1 ≡ 1(mod m1), and l1 m1l2, where n = mi(di +1) + qi and 0 ≤ qi ≤ di.