A Study on Estimation Method of Communication Area using Cooperated Monitoring of Communication Quality in Cognitive Radio
Tatsuya MURAYAMA*, HideichiSASAOKA* and HisatoIWAI*
(Received April 9, 2015)
In the field of Cognitive Radio, to avoid influence to the communication quality of PU (Primary User) and to realize the communication of SU (Secondary User) simultaneously can be technical subjects. In these issues, the sensing technology where the PU signals are detected has been proposed, however, neither the communication area of PU nor the influence to communication quality of PU from SU cannot be estimated sufficiently. In this paper, the method of how to decide the communication area based on communication quality estimation which is a technique by using pseudo error is proposed and the numerical results based on simulation are discussed as well. According to the results, the effectiveness of the proposal is shown. Moreover, the influence to the communication quality of PU by SU is shown by using the relationship between the power and distance as well.
.H\ZRUGV cognitive radio
㸪
communication area estimation㸪
pseudo bit error࣮࣮࢟࣡ࢻ
ࢥࢢࢽࢸࣈ↓⥺㸪㏻ಙ࢚ࣜ᥎ᐃ㸪ᨃఝࣅࢵࢺㄗࡾ
ࢥࢢࢽࢸࣈ↓⥺࠾ࡅࡿ㏻ಙရ㉁ࡢ༠ㄪࣔࢽࢱࣜࣥࢢ
ࢆ⏝࠸ࡓ㏻ಙ࢚ࣜ᥎ᐃἲࡢ᳨୍ウ
ᮧᒣ 㐩ဢ㸪➲ᒸ ⚽୍㸪ᒾ ㄔே
ࡣࡌࡵ
㏆ᖺ㸪↓⥺㏻ಙ➃ᮎ⏝⪅ࡀⳘቑຍࡋ࡚࠸ࡿ㸬 ࡋࡋ㸪⛣ື㏻ಙ⏝ྍ⬟࡞࿘Ἴᩘᖏࡢ༙ࡣ᪤
ࡾᙜ࡚ࡽࢀ࡚࠾ࡾ㸪ᑗ᮶ⓗ࿘Ἴᩘࡢ㐕㏕ࡀᠱ ᛕࡉࢀ࡚࠸ࡿ㸬ࡇࡢၥ㢟ࢆゎỴࡍࡿ᪉ἲࡢ୍ࡘࡋ
࡚ࢥࢢࢽࢸࣈ↓⥺ࡀ⪃࠼ࡽࢀ࡚࠸ࡿ㸬ࢥࢢࢽࢸ
ࣈ↓⥺ࡣ㸪࿘Ἴᩘࡢ⏝ᶒࢆᣢࡘ᪤Ꮡ↓⥺ࢩࢫ ࢸ࣒ࡀᖖඃඛⓗ࡛࠶ࡿ࠸࠺᮲௳ࡢୗ࡛㸪᪂つཧ ධࢩࢫࢸ࣒ࡀ୍ⓗ᪤Ꮡ↓⥺ࢩࢫࢸ࣒ࡢ࿘Ἴᩘ
ࢆ2ḟⓗ⏝ࡋ࡚㏻ಙࢆ⾜࠺↓⥺᪉ᘧ࡛࠶ࡾ㸪࿘
Ἴᩘ⏝ຠ⋡ࢆ㧗ࡵࡿࡶࡢࡋ࡚㸪㏆ᖺὀ┠ࡉࢀ࡚
࠸ࡿ㸬ࡋࡋ㸪ࢥࢢࢽࢸࣈ↓⥺ࡣ㸪ᐇ㝿ᐇ⌧
*Department of Electronics, Doshisha University, Kyotanabe, Kyouto, 610-0321, Japan Telephone: +81-774-65-6355, FAX: +81-774-65-6255, Email: [email protected]
ࢆྍ⬟ࡍࡿࡓࡵከࡃࡢ᪂ࡋ࠸ᢏ⾡➼ࢆᚲせ
ࡍࡿ1, 2)㸬
ࢥࢢࢽࢸࣈ↓⥺ࡢᐇ⌧ࢆྍ⬟ࡍࡿࡓࡵࡢ㔜 せ ࡞ ᢏ ⾡ ࡢ ୍ ࡘ ࡋ ࡚ ࣉ ࣛ ࣐ ࣜ ࣘ ࣮ ࢨ (PU:
Primary User) ࡽࡢ㏦ಙಙྕࢆࢭ࢝ࣥࢲ࣮ࣜࣘࢨ (SU: Secondary User) ࡀ᳨ฟࡍࡿࢫ࣌ࢡࢺࣝࢭࣥࢩ
ࣥࢢᢏ⾡ࡀ࠶ࡿ 3)㸬ࢫ࣌ࢡࢺࣝࢭࣥࢩࣥࢢᢏ⾡ࡣ㸪
↓⥺ᶵࡀ㸪ࢫ࣌ࢡࢺࣝࡢ㛫ⓗ✵㛫ⓗ⏝≧ἣࢆほ ࡋ㸪⏝ྍ⬟⏝ྍ⬟ࢆุ᩿ࡍࡿᢏ⾡࡛࠶
ࡾ㸪ࢫ࣌ࢡࢺࣝ⏝ࡢඃඛᶒࢆ⪃៖ࡋࡓືⓗ࡞࿘Ἴ
ᩘࡢඹ⏝ࢆᐇ⌧ࡍࡿࡓࡵࡢ㔜せ࡞ᢏ⾡࡛࠶ࡿ㸬ࡑࡢ ࢭࣥࢩࣥࢢ᪉ἲࡣࡁࡃศࡅ࡚㟁ຊᇶ‽᳨ฟ㸪࿘
ᮇᐃᖖᛶࢆ⏝࠸ࡓࢭࣥࢩࣥࢢ㸪࣐ࢵࢳࢻࣇࣝࢱࢆ
⏝࠸ࡿࢭࣥࢩࣥࢢࡀ࠶ࡿ㸬ࡑࡢ୰࡛ࡶ㸪᭱ࡶỗ⏝ᛶ ࡀ㧗࠸ࡶࡢࡋ࡚㟁ຊᇶ‽᳨ฟࡀᣲࡆࡽࢀ࡚࠸ࡿ㸬 ࡇࡢ᪉ᘧࡣ㸪࣐ࢵࢳࢻࣇࣝࢱࢆ⏝࠸ࡿࢭࣥࢩࣥࢢ
␗࡞ࡾ㸪ᚲせ࡞㏦ಙಙྕࡢሗࡀせ࡛ㄪࡍࡿ
ᚲせࡀ࡞ࡃ㸪ィ⟬㔞ࡶᑡ࡞࠸ 3-7)㸬ࡋࡋ㸪ࢫ࣌ࢡ ࢺࣝࢭࣥࢩࣥࢢ࡛ࡣ㸪PUࡢ㏦ಙಙྕࡀ᳨ฟࡉࢀࡿ
ࡢࡳ࡛㸪SUࡀ㏦ಙࡋࡓሙྜ PU࠼ࡿᙳ㡪ࡲ
࡛ࡣホ౯࡛ࡁ࡞࠸㸬ࡑࡢࡓࡵ㸪PUࡢ㏻ಙ㞀ᐖ
࡞ࡽ࡞࠸ࡓࡵࡣ༑ศ࣐࣮ࢪࣥࢆຍ࠼࡚㸪SUࡢ
⏝ྍ⬟㡿ᇦࢆỴࡵࡿᚲせࡀ࠶ࡿ㸬ࡇࡢࡓࡵ㸪SU ࡢ㏦ಙྍ⬟㡿ᇦࢆ㐣ᑠホ౯ࡍࡿྍ⬟ᛶࡀ࠶ࡿ㸬ࡇࢀ
ᑐࡋ࡚㸪ࡼࡾṇ☜SUࡢ㏦ಙྍ⬟㡿ᇦࢆỴࡵࡿ
ࡣ㸪PU ࠾ࡅࡿ㏻ಙရ㉁ࡀᇶ‽ࢆ‶ࡓࡍ⠊ᅖ (௨ୗ㸪PUࡢ㏻ಙ࢚ࣜࡍࡿ) ࢆ▱ࡿࡇ㸪㏻ಙ
࢚ࣜෆࡢPU ࡢ➃ᮎᑐࡋ࡚㸪SUࡢ㏦ಙࡼࡿ
㏻ಙရ㉁ࡢຎࡀチᐜ್௨ෆ࡞ࡿSUࡢ࢚ࣜࢆ
Ỵࡵࡿࡇࡀ㔜せ࡞ࡿ㸬
ࡑࡇ࡛ᮏ✏࡛ࡣ㸪ᨃఝࣅࢵࢺㄗࡾ᥎ᐃᡭἲࢆ⏝࠸
ࡓ㏻ಙရ㉁ࡢ༠ㄪࣔࢽࢱࣜࣥࢢࡼࡿPUࡢ㏻ಙ࢚
ࣜ᥎ᐃࢆᥦࡍࡿ8)㸬ᨃఝࣅࢵࢺㄗࡾࡼࡿ㏻ಙ ရ㉁᥎ᐃᡭἲࡣ㸪᪤▱ࡢሗಙྕࡢ㏦ಙࢆᚲせࡏ ࡎ㸪㏦ಙሗࡀ௵ពࡢሙྜࡶ᥎ᐃྍ⬟࡞᪉ἲ࡛࠶
ࡿ9)㸬ࡲࡓ㸪PUࡢ㏻ಙ࢚ࣜຍ࠼㸪SUࡀሗಙ
ྕࢆ㏦ಙࡍࡿ㝿㸪ඃඛᶒࢆ᭷ࡍࡿPUࡀ୍ᐃࡢ㏻
ಙရ㉁ࢆᦆ࡞ࢃ࡞࠸チᐜ⠊ᅖࢆࢩ࣑࣮ࣗࣞࢩࣙࣥ
ࡼࡗ࡚ホ౯ࡍࡿࡇࡼࡗ࡚ᥦ᪉ἲࡢ᭷ពᛶ
ࢆ♧ࡍ10)㸬
ࢥࢢࢽࢸࣈ↓⥺࠾ࡅࡿ㏻ಙ࢚ࣜ᥎ᐃἲ ࢥࢢࢽࢸࣈ↓⥺ࡢᴫせせ⣲ᢏ⾡
ࢥࢢࢽࢸࣈ↓⥺ࡣ㸪࿘ᅖࡢ↓⥺⎔ቃࢆㄆ▱ࡋ㸪
࣮ࣘࢨࡢせồᛂࡌ࡚㐺ᛂⓗ㏻ಙ᪉ᘧ㸪ኚㄪ᪉ᘧ㸪
࿘Ἴᩘ㸪ࢹ࣮ࢱ࣮ࣞࢺ࡞ࡢ㏻ಙࣃ࣓࣮ࣛࢱࢆ⮬ᚊ
ⓗタᐃࡋ㸪↓⥺ᶵࢆᵓᡂࡋ㸪㏻ಙࡍࡿ↓⥺ࢩࢫ ࢸ࣒࡛࠶ࡿ㸬ࢥࢢࢽࢸࣈ↓⥺ࢩࢫࢸ࣒ࡣ㸪࿘ᅖ ࡢ↓⥺⎔ቃࡢほᐹࡽ↓⥺㏻ಙࡢᐇ⾜ࡲ࡛ࢆࢥࢢ ࢽࢸࣈࢧࢡࣝ (cognitive cycle) ࠸࠺ᴫᛕ࡛
⾲ࡋ࡚࠸ࡿ㸬ࢥࢢࢽࢸࣈࢧࢡࣝࡣ⎔ቃࡢ㑄⛣ࢆ
⥭ᛴᛶ࡞ࡼࡗ࡚」㞧ሙྜศࡅࡋ࡚ᵓᡂࡉࢀ
࡚࠸ࡿ㸬ࡇࡢࢧࢡࣝࢆ⡆᫆ࡋ㸪ูࡍࡿ㸪ほ ᐹ㸪ィ⏬㸪ุ᩿࣭㐺ᛂ㸪ᐇ⾜ࡢ4ࡘࡢᵓᡂ࡛ᡂࡗ࡚
࠾ࡾ㸪ࡇࡢᵓᡂࡢࢧࢡࣝࡼࡗ࡚ᶵ⬟ࡢᵓᡂࢆ
⾜࠸㸪࿘ᅖࡢ↓⥺⎔ቃ㐺ᛂࡍࡿࡇࡀྍ⬟࡞ࡿ㸬 ḟࢥࢢࢽࢸࣈࢧࢡࣝࡢᴫᛕᅗࢆ♧ࡍ㸬
Fig. 1. Concept of cognitive cycle.
ࡇࡢࡼ࠺࡞ᴫᛕ࠾ࡅࡿࢥࢢࢽࢸࣈ↓⥺ࡣ
ࡁࡃศࡅ࡚2ࡘࡢࢩࢫࢸ࣒ᙧែศ㢮ࡉࢀࡿ㸬1 ࡘࡣ࣊ࢸࣟࢪࢽࢫᆺࢥࢢࢽࢸࣈ↓⥺࠸࠸㸪᪤
Ꮡࡢ↓⥺ࢩࢫࢸ࣒ࡀ࿘ᅖࡢ↓⥺⎔ቃࢆㄆ▱ࡋ㸪」ᩘ
ࡢ↓⥺㏻ಙࢩࢫࢸ࣒ࢆ⎔ቃᛂࡌ࡚࠸ศࡅࡿࡇ
࡛ࢿࢵࢺ࣮࣡ࢡࢆຠ⋡ⓗ⏝ࡋ࡚㏻ಙࢆ⾜࠺
ࢩࢫࢸ࣒࡛࠶ࡿ㸬ࡶ࠺1ࡘࡣࢲࢼ࣑ࢵࢡࢫ࣌ࢡࢺ
ࣝࢡࢭࢫ (DSA: Dynamic Spectrum Access) ᆺࢥ ࢢࢽࢸࣈ↓⥺࠸࠸㸪᪤Ꮡ↓⥺ࢩࢫࢸ࣒ࡋ࡚
ࡾᙜ࡚ࡽࢀ࡚࠸ࡿ࿘Ἴᩘᖏᇦࢆࢥࢢࢽࢸࣈ↓⥺
ࢩࢫࢸ࣒ࡀ2 ḟⓗ⏝ࡍࡿ᪉ἲ࡛࠶ࡿ㸬DSA ࡛ ࡣ㸪᪤Ꮡ↓⥺ࢩࢫࢸ࣒ࡢ⏝≧ἣࢆ⪃៖ධࢀ࡚㸪
┦ᖸ΅࡞ࡽ࡞࠸ࡼ࠺㏻ಙࢆ⾜࠺ࢩࢫࢸ࣒
࡛࠶ࡿ㸬ᮏ◊✲࡛ࡣ㸪DSA ࠾ࡅࡿࢥࢢࢽࢸࣈ
↓⥺ࢆᐃࡋ࡚ᥦࡍࡿ㸬
ࡇࡢࢩࢫࢸ࣒ࡣ㸪࣮ࣘࢨࡀ⏝ࡋ࡚࠸ࡿ↓⥺᪉ᘧ
ࡸ࿘Ἴᩘࡢ⏝≧ἣࢆㄆ▱ࡋ㸪⏝࡛ࡁࡿࡢ㏻ಙ ࢩࢫࢸ࣒ษࡾ᭰࠼ࡿࡇ࡛㸪₯ᅾⓗ⏝ࡉࢀ࡚
࠸࡞࠸࿘Ἴᩘ㈨※ࢆぢࡘࡅࡿࡇࡸ㸪࿘Ἴᩘࡢ⏝
ຠ⋡ࢆ㧗ࡵ㸪㏻ಙࢺࣛࣇࢵࢡࡢΰ㞧ࢆ㍍ῶࡍࡿࡇ
ࡀ࡛ࡁࡿ᪉ᘧ࡛࠶ࡾ㸪࿘Ἴᩘࡢ㈨※ၥ㢟ࢆゎỴࡍ
ࡿ᪉ἲࡋ࡚ᮇᚅࡉࢀ࡚࠸ࡿ㸬
DSA ࡛ࡣ㸪᪤Ꮡ↓⥺ࢩࢫࢸ࣒ࢥࢢࢽࢸࣈ↓
⥺ࢩࢫࢸ࣒ࡀྠ୍ࡢ࿘Ἴᩘࢆඹ⏝ࡍࡿࡇ࡛࿘Ἴ
ᩘ⏝ຠ⋡ࡢᨵၿࢆᅗࡗ࡚࠸ࡿ㸬ࡇࡢࡼ࠺࡞࿘Ἴᩘ
ඹ⏝࠾ࡅࡿ᪤Ꮡࢩࢫࢸ࣒ࢆࣉ࣐ࣛࣜࢩࢫࢸ࣒㸪 ࢥࢢࢽࢸࣈ↓⥺ࢩࢫࢸ࣒ࢆࢭ࢝ࣥࢲࣜࢩࢫࢸ࣒
ࡪ㸬࿘Ἴᩘඹ⏝ࢩࢫࢸ࣒࡛ࡣ࿘Ἴᩘࡢ⏝ᶒ
ࢆᣢࡘࣉ࣐ࣛࣜࢩࢫࢸ࣒ࡀᖖඃඛⓗ࡛࠶ࡿࡓ
ࡵ㸪ࢭ࢝ࣥࢲࣜࢩࢫࢸ࣒ࡣ┦ᖸ΅ࢆᅇ㑊ࡋ㸪ࣉࣛ
࣐ࣜࢩࢫࢸ࣒ࡢ㏻ಙရ㉁ࢆಖࡗࡓୖ࡛㸪㏻ಙࢆ⾜
࠺ᚲせࡀ࠶ࡿ㸬ࡇࡢࡁ㸪ࢭ࢝ࣥࢲࣜࢩࢫࢸ࣒ࡽ
ࣉ࣐ࣛࣜࢩࢫࢸ࣒ࡢᖸ΅ࢆᖸ΅㸪ࣉ࣐ࣛࣜ
ࢩࢫࢸ࣒ࡽࢭ࢝ࣥࢲࣜࢩࢫࢸ࣒ࡢᖸ΅ࢆ⿕ᖸ
΅ࡪ㸬ḟᖸ΅⿕ᖸ΅ࡢ㛵ಀࢆ♧ࡍ㸬࡞࠾㸪 0࠾ࡅࡿPUTX㸪PURXࡣࡑࢀࡒࢀࣉ࣐ࣛࣜࢩࢫ ࢸ࣒ࡢ㏦ಙᒁ㸪ཷಙᒁࢆ⾲ࡍ㸬
Fig. 2. Mutual interference in the frequency common use system.
DSA ࡛ࡣ㸪≉ࢭ࢝ࣥࢲࣜࢩࢫࢸ࣒ࡀ↓⥺⎔ቃ
㛵ࡍࡿሗࢆ㞟ࡵ࡚㸪ࣉ࣐ࣛࣜࢩࢫࢸ࣒ࡢ
ᖸ΅ࢆ㑊ࡅࡿࡇࡀ㔜せ࡞ࡿ㸬ᖸ΅ࢆᅇ㑊ࡍࡿ᪉ ἲࡋ࡚ࡣ㸪ࢩࢫࢸ࣒㛫ࡢ✵㛫ࢆά⏝ࡍࡿ᪉ἲ㸪␗
࡞ࡿ࿘Ἴᩘࢆ⏝ࡍࡿ᪉ἲ㸪␗࡞ࡿ㛫ࢆ⏝ࡍࡿ
᪉ἲࡢ㸱ࡘࡀᣲࡆࡽࢀࡿ㸬ࡑࡇ࡛㸪ࡇࢀࡽࡢ⏝ࡢ
ྍྰࡢ᳨ฟࡀ㔜せ࡞ࡿ㸬
ࣉ࣐ࣛࣜಙྕࡢ᭷↓ࢆุ᩿ࡍࡿࡇࡼࡗ࡚
ࢭ࢝ࣥࢲࣜࢩࢫࢸ࣒ࡢ㏦ಙࡢྍྰࡢุ᩿ࡀྍ⬟
࡞ࡿࢫ࣌ࢡࢺࣝࢭࣥࢩࣥࢢᢏ⾡ࡀ࠶ࡿ㸬ࢫ࣌ࢡࢺࣝ
ࢭࣥࢩࣥࢢᢏ⾡࡛ࡣ㞃ࢀ➃ᮎၥ㢟ࡀ⏕ࡌ࡞࠸ࡼ࠺
ࡍࡿࡓࡵ㸪ࣉ࣐ࣛࣜಙྕࡀ㞧㡢௨ୗ࡛ࡢࣞ࣋
࡛ࣝ࠶ࡗ࡚ࡶ᳨ฟࡍࡿᚲせࡀ࠶ࡾ㸪㧗ᛶ⬟࡞᳨ฟᢏ
⾡ࡀᚲせ࡞ࡿ㸬ࡲࡓ㸪༢⊂ࣀ࣮ࢻࡢࢭࣥࢩࣥࢢ࡛
ࡣ㸪↓⥺㏻ಙ≉᭷ࡢ⌧㇟࡛࠶ࡿࣇ࢙࣮ࢪࣥࢢࡼࡿ
ᒁᡤⓗ࡞ಙྕࡢⴠࡕ㎸ࡳࡸ㸪㞀ᐖ≀࡞ࡢᙳ㡪ࡼ
ࡾಙྕࡀ᳨ฟ࡛ࡁ࡞࠸ሙྜࡀ࠶ࡿ㸬ࡑࡢࡓࡵ」ᩘ➃ ᮎࡼࡿࢭࣥࢩࣥࢢࢆ⾜࠸㸪ሗඹ᭷ࡍࡿࡇ࡛ಙ
ྕࡢ᳨ฟࢆྍ⬟ࡍࡿ༠ㄪࢭࣥࢩࣥࢢᢏ⾡ࡀᚲせ
࡞ࡿ㸬
ࢫ࣌ࢡࢺࣝࢭࣥࢩࣥࢢᢏ⾡ࡣ㸪㟁ຊᇶ‽᳨ฟ㸪࿘
ᮇᐃᖖᛶࢆ⏝࠸ࡓࢭࣥࢩࣥࢢ㸪࣐ࢵࢳࢻࣇࣝࢱࢆ
⏝࠸ࡓࢭࣥࢩࣥࢢࡁࡃศ㢮࡛ࡁࡿ㸬㟁ຊᇶ‽᳨
ฟࡣ᳨ฟࡍࡿࡢኚㄪ᪉ᘧࡸࢩ࣮ࣥ࣎ࣝࣞࢺ࡞
ࡢಙྕሗࡀせ࡛㸪᳨ฟ࠾ࡅࡿฎ⌮ࡀᑡ࡞࠸ࡇ
ࡀⅬ࡛࠶ࡿ㸬୍᪉㸪࿘ᮇᐃᖖᛶࢆ⏝࠸ࡓࢭࣥࢩ
ࣥࢢཬࡧ࣐ࢵࢳࢻࣇࣝࢱࢆ⏝࠸ࡓࢭࣥࢩࣥࢢ࡛
ࡣࣉ࣐ࣛࣜࢩࢫࢸ࣒ࡢ㏦ಙಙྕࡢሗࡀከࡃᚲ せ࡞ࡿ㸬࿘ᮇᐃᖖᛶࢆ⏝࠸ࡓࢭࣥࢩࣥࢢࡣࣇ࢙࣮
ࢪࣥࢢ࡞ࡢᙳ㡪ᙉࡃ㸪ࡲࡓኚㄪ᪉ᘧࡸࢩࣥ࣎ࣝ
࣮ࣞࢺࡢ␗࡞ࡿಙྕࡢ㆑ูࡀྍ⬟࡛㟁ຊᇶ‽᳨ฟ
ẚ࡚㧗⢭ᗘ࡞ࢭࣥࢩࣥࢢࡀྍ⬟࡞ࡿ㸬࣐ࢵࢳ ࢻࣇࣝࢱࡣ᭱ࡶ㧗࠸᳨ฟ⢭ᗘࡀᮇᚅ࡛ࡁࡿᡭἲ
࡛࠶ࡿࡀ㸪ࣉ࣐ࣛࣜࢩࢫࢸ࣒ࡢ㏦ಙಙྕࢆࢭ࢝ࣥ
ࢲࣜࢩࢫࢸ࣒ࡀㄪࡍࡿᚲせࡀ࠶ࡿࡓࡵ㸪ࡼࡾከࡃ ࡢ㏦ಙಙྕ㛵ࡍࡿሗࡀᚲせ࡞ࡿ㸬࿘ᅖࡢ↓⥺
⎔ቃࡢኚᰂ㌾ᑐᛂࡍࡿࢥࢢࢽࢸࣈ࠾࠸
࡚ࡣ㸪㏦ಙಙྕࡢሗࢆከࡃ▱ࡾ㸪᳨ฟࢆ⾜࠺᪉ἲ ࡣ⌧ᐇⓗ㞴ࡋ࠸㸬ࡑࡢࡓࡵ㸪ࡼࡾỗ⏝ᛶࡀ㧗ࡃ㸪
᭱ప㝈ࡢ๓ሗࡢࡳࢆᚲせࡍࡿ㟁ຊᇶ‽ࡼ
ࡿࢫ࣌ࢡࢺࣝࢭࣥࢩࣥࢢࡀ㐺ࡋ࡚࠸ࡿ㸬
ࡋࡋ㸪㟁ຊᇶ‽᳨ฟ࡛ࡣ㸪ࣉ࣐ࣛࣜࢩࢫࢸ࣒
ࡢ㏦ಙಙྕࡀ᳨ฟࡉࢀࡿࡢࡳ࡛㸪ࢭ࢝ࣥࢲࣜࢩࢫࢸ
࣒ࡀ㏦ಙࡋࡓሙྜࣉ࣐ࣛࣜࢩࢫࢸ࣒࠼ࡿ
PUTx
Transmission station
PURx
Receiving station
SU SU
Primary system
Secondary system Receiving
interference Giving
interference
ᙳ㡪ࡲ࡛ࡣ༑ศホ౯࡛ࡁ࡞࠸㸬ࡑࡢࡓࡵ㸪ࢭ࢝ࣥ
ࢲࣜࢩࢫࢸ࣒ࡣࣉ࣐ࣛࣜࢩࢫࢸ࣒ࡢ㏻ಙࡀྍ⬟
࡞ࡿ㟁ຊࡼࡾ༑ศᑠࡉ࠸㟁ຊࡢಙྕࡲ᳨࡛ฟ ࡋ㸪ࡉࡽࡣ༑ศ㞳ࢀࡓሙᡤࢆ⏝ྍ⬟㡿ᇦࡍ
ࡿᚲせࡀ࠶ࡿ㸬ࡘࡲࡾ㸪༑ศ࡞ಙྕᙉᗘࡢῶ⾶ࢆ☜
ಖࡋ࡚࠾ࡾ㸪ሙྜࡼࡗ࡚ࡣ㸪ࡉࡽ࣐࣮ࢪࣥࢆຍ
࠼࡚⏝ྍ⬟㡿ᇦࢆỴࡵ࡚࠸ࡿ㸬ࡇࡢࡓࡵ㸪SUࡢ
㏦ಙྍ⬟㡿ᇦࢆ㐣ᑠホ౯ࡍࡿྍ⬟ᛶࡀ࠶ࡿ㸬ࡇࢀ
ᑐࡋ࡚㸪ࡼࡾṇ☜SUࡢ㏦ಙྍ⬟㡿ᇦࢆỴࡵࡿ
ࡣ㸪PUࡢ㏻ಙ࢚ࣜࢆ▱ࡿࡇ㸪㏻ಙ࢚ࣜෆࡢ PUࡢ➃ᮎᑐࡋ࡚㸪SUࡢ㏦ಙࡼࡿ㏻ಙရ㉁ࡢຎ
ࡀチᐜ್௨ෆ࡞ࡿSUࡢ࢚ࣜࢆỴࡵࡿࡇࡀ 㔜せ࡞ࡿ㸬ࡑࡢࡓࡵࡣ㸪㏻ಙရ㉁ࡢ᥎ᐃἲࡀ㔜 せ࡞ࡿ㸬
㏻ಙရ㉁᥎ᐃἲࡢ᳨ウ
㏻ಙရ㉁ࢆồࡵࡿࡣᮏ᮶㸪㏦ಙሗࡀ᪤▱࡛࠶
ࡿᚲせࡀ࠶ࡿ㸬ࡋࡋࢥࢢࢽࢸࣈ↓⥺࠾࠸࡚ࡣ㸪
㏦ಙಙྕࡣ᪤▱࡛࡞࠸㸬ࡑࡢࡓࡵ㸪SUࡀ㏻ಙရ㉁
ࢆ᥎ᐃࡍࡿ᪉ἲࡋ࡚ࡣ㸪PUࡢ㏦ಙಙྕࡀ௵ព࡛
࠶ࡗ࡚ࡶồࡵࡽࢀࡿ᪉ἲࡀ⌧ᐇⓗ࡛࠶ࡿ㸬PUࡢ㏦
ಙಙྕࡀ௵ព࡛࠶ࡗ࡚ࡶ㏻ಙရ㉁ࢆ᥎ᐃ࡛ࡁࡿ᪉ ἲࡋ࡚㸪ཷಙ㟁ຊࡽSNR (Signal to Noise Ratio)
ࢆồࡵ࡚ࣅࢵࢺㄗࡾ⋡ (BER: Bit Error Rate) ࢆ᥎ ᐃࡍࡿ᪉ἲ㸪EVM (Error Vector Magnitude) ࢆ⏝࠸
ࡓ᪉ἲࡀ୍⯡ⓗᣲࡆࡽࢀࡿ 11, 12)㸬ࡋࡋ㸪ཷಙ 㟁ຊࡽ᥎ᐃࡍࡿ᪉ἲ࡛ࡣ㸪ᖸ΅ࡀ࠶ࡿሙྜࡣᖸ΅
ࡶ㏦ಙ㟁ຊぢ࡞ࡋ࡚ࡋࡲ࠺ࡓࡵ㸪SNR ࡣᮏ᮶ࡼ
ࡾࡶ㧗ࡃ᥎ᐃࡉࢀ࡚ࡋࡲ࠺㸬EVMࢆ⏝࠸ࡓ᪉ἲࡣ㸪 ᐃࡋࡓಙྕ⌮ಙྕࡢᕪࢆ⏝࠸࡚㏻ಙရ㉁ࢆ
᥎ᐃࡍࡿࡶࡢ࡛࠶ࡾᖸ΅ࢆ⪃៖ࡋࡓ᥎ᐃࡀྍ⬟࡛
࠶ࡿࡀ㸪ࣅࢵࢺุᐃࡢ㜈್㏆࠾ࡅࡿ☜⋡ศᕸࡀ ㄗࡾ⋡ᐦ᥋㛵ಀࡍࡿࡓࡵ㸪㧗⢭ᗘ࡞ホ౯ࡀᚓ㞴
࠸㸬
ࡑࡇ࡛ᮏ◊✲࡛ࡣ㸪᪤▱ಙྕࢆᚲせࡏࡎ㏻ಙ ရ㉁ࢆ᥎ᐃ࡛ࡁ㸪ᖸ΅ࡢᙳ㡪ࡶᑐᛂ࡛ࡁࡿᨃఝࣅ
ࢵࢺㄗࡾࡼࡿ㏻ಙရ㉁᥎ᐃἲࢆ⏝࠸ࡿ㸬
ᨃఝࣅࢵࢺㄗࡾࡢཎ⌮≉ᛶ
ᨃఝࣅࢵࢺㄗࡾࡼࡿ㏻ಙရ㉁᥎ᐃἲࡣ㸪ཷಙ
ഃ࠾࠸࡚ㄗࡾ⋡≉ᛶࡀ࠶ࡿ⛬ᗘຎࡍࡿせᅉࢆ
ேⅭⓗຍ࠼㸪ࡇࡢቑຍࡋࡓㄗࡾ⋡ (ᨃఝࣅࢵࢺㄗ
ࡾ)ࢆ᳨ฟࡋ㸪๓ồࡵ࡚࠾࠸ࡓᨃఝㄗࡾࡢⓎ⏕
⋡ (PBER: Pseudo Bit Error Rate) ᐇ㝿ࡢㄗࡾ⋡
(௨ୗActual BER) ࡢᑐᛂ㛵ಀࢆ⏝࠸࡚BERࢆ᥎ ᐃ (௨ୗ Estimated BER) ࡍࡿ᪉ἲ࡛࠶ࡿ㸬ࡇࡢ᪉ ἲ࡛ࡣ㸪᪤▱ಙྕࡢ㏦ಙࢆᚲせࡏࡎ㸪ࣅࢵࢺ⣔ิ
ࡀ᫂࡞ሗಙྕࡼࡾᐇ⌧ྍ⬟࡛࠶ࡿ㸬
ᨃఝࣅࢵࢺㄗࡾࡢⓎ⏕᪉ἲࡣ㞧㡢ࢆຍࡍࡿ
᪉ἲ㸪᳨Ἴ┦ࢆᅇ㌿ࡉࡏࡿ᪉ἲ➼㸪࠸ࡃࡘ᪉ἲ ࡀ࠶ࡿࡀ㸪ᮏ◊✲࡛ࡣุᐃ㍈ࢆ࢜ࣇࢭࢵࢺࡉࡏࡿ᪉ ἲࢆ⏝࠸࡚ホ౯ࡍࡿ9)㸬
Fig. 3.
Concept of pseudo error and example of the receiver constitution.
Fig. 3 ࡣ㸪BPSKኚㄪ࡛ࡢุᐃ㍈ࢆ࢜ࣇࢭࢵࢺࡉ ࡏࡿ᪉ἲ࠾ࡅࡿᨃఝㄗࡾⓎ⏕᪉ἲࡢᴫᛕᅗࡑ
ࢀࢆᐇ⌧ࡍࡿཷಙᶵࡢᵓᡂࢆ♧ࡋ࡚࠸ࡿ㸬࡞࠾㸪
Fig. 3 ࡛ࡣಙྕᖜࢆ1ṇつࡋ࡚࠸ࡿ㸬㏻ᖖࡢ
ཷಙ࡛ࡣ2ࡘࡢಙྕⅬࡢ୰ኸ (A0) ࢆ㜈್ (Th.) ࡋ࡚ཷಙࣅࢵࢺ⣔ิࢆุᐃࡍࡿ㸬ࡑࢀᑐࡋ࡚㸪ಙ
ྕⅬ᪉ྥa/2-a/2ࡔࡅ࢜ࣇࢭࢵࢺࡋࡓ㜈್ (A+
A-) ࢆ⏝࠸ุ࡚ᐃࡍࡿ㸬ࡇࢀࡽࡢࣅࢵࢺࡀ␗࡞ࡗ ࡓሙྜᨃఝࣅࢵࢺㄗࡾࡀⓎ⏕ࡋࡓࡍࡿ㸬ࡍ࡞ࢃ
ࡕ㸪ࡇࡢ᪉ἲࡼࡗ࡚Ⓨ⏕ࡋࡓᨃఝㄗࡾࣅࢵࢺࡣ㸪
Fig. 3 ࡢ⥙ࡅࡢ㡿ᇦཷಙಙྕࡀᏑᅾࡍࡿሙྜ
┦ᙜࡍࡿ㸬ཷಙࣅࢵࢺ⣔ิㄗࡾࡀⓎ⏕ࡍࡿࡢࡣ㸪 㞧㡢࡞ࡢᙳ㡪ࡼࡾ㸪ุᐃ㍈ (A0) ࢆ㉺࠼࡚ᮏ᮶ ࡢಙྕⅬࡣ㏫ࡢ༙ᖹ㠃ཷಙಙྕⅬࡀ⛣ືࡍࡿ
ሙྜ࡛࠶ࡿ㸬ࡇࡢ⌧㇟ࡀⓎ⏕ࡍࡿ☜⋡㸪Fig. 3 ࡢ
⥙ࡅ㒊ศཷಙಙྕⅬࡀᏑᅾࡍࡿ☜⋡ࡣ୍ᐃ ࡢ┦㛵ࡀ࠶ࡿ㸬ࡇࢀࡀᨃఝࣅࢵࢺㄗࡾࡼࡿ BER ᥎ᐃࡢཎ⌮࡛࠶ࡿ㸬࡞࠾㸪ࡇࡇ࡛ࡣBPSK᪉ᘧࢆᑐ
Q
I 1
a
BPSK Demod.
Th.=
BPSK Demod.
Th.=
BPSK Demod.
Th.=
XOR XOR: The exclusive OR
Received bit stream
Pseudo error of bit stream Received
signal
㇟ࡑࡢཎ⌮ࢆㄝ᫂ࡋࡓࡀ㸪QPSK᪉ᘧ࡞ࡢኚ ㄪ᪉ᘧࡶ㐺⏝ྍ⬟࡛࠶ࡿࡇࡀ▱ࡽࢀ࡚࠸ࡿ9) 㸬
ᨃఝࣅࢵࢺㄗࡾࢆ⏝࠸ࡓ㏻ಙရ㉁᥎ᐃἲ࡛ࡣ㸪
Fig. 4 ࠾ࡅࡿᖸ΅ࡀᏑᅾࡋ࡞࠸ሙྜ♧ࡍࡼ࠺
࡞࢞࢘ࢫ (AWGN: Additive White Gaussian Noise) ఏ㏦㊰ᑐࡍࡿQPSKኚㄪ࡛ࡢActual BERPBER ࡢ≉ᛶࢆ๓ồࡵ࡚࠾ࡃ㸬࡞࠾㸪Fig. 4࡛ࡣ㸪ุ
ᐃ㍈࢜ࣇࢭࢵࢺ㔞aࢆ0.3ࡋ࡚࠸ࡿ㸬ḟ㏦ಙ
ሗࡀᮍ▱ࡢሙྜ PBER ࢆ ᐃࡋ㸪๓ồࡵࡓ Actual BERPBERࡢ㛵ಀࢆ⏝࠸࡚BERࢆ᥎ᐃࡋ㸪 ࡇࡢ᥎ᐃ್ࢆEstimated BERࡍࡿ㸬
Fig. 4. Characteristic of BER and PBER (AWGN channel, QPSK, a=0.3).
Fig. 5. Estimated characteristic in case of interference (AWGN channel, QPSK, a=0.3).
ᖸ΅ࡀᏑᅾࡍࡿ⎔ቃୗ࠾࠸࡚ࡶ㸪PBERࢆ ᐃ ࡋ㸪࢞࢘ࢫఏ㏦㊰࠾ࡅࡿᖸ΅ࡢᏑᅾࡋ࡞࠸ሙྜࡢ
PBERActual BERࡢ㛵ಀࡽ㸪Estimated BERࢆ ồࡵࡿ㸬ᖸ΅ࡀᏑᅾࡍࡿ⎔ቃୗ࡛ࡢActual BER Estimated BERࡢ㛵ಀࢆFig. 5 ♧ࡍ㸬SIR (Signal to Interference Ratio) ࡀ10dB௨ୖࡢሙྜ⢭ᗘⰋࡃ᥎ᐃ ࡉࢀ࠾ࡾ㸪᭷ຠ࡛࠶ࡿࢃࡿ㸬
ࡲࡓ㸪࣮ࣞࣜࣇ࢙࣮ࢪࣥࢢ (Rayleigh fading) ఏ
㏦㊰࠾࠸࡚ࡶྠᵝࡢࡇࡀྍ⬟࡛࠶ࡾ㸪ᨃఝࣅࢵ
ࢺㄗࡾActual BERࡣFig. 6 ࡢࡼ࠺࡛࠶ࡾ㸪ࡇࡢ
Actual BERPBERࡢ㛵ಀࢆ๓ồࡵࡿ㸬
Fig. 6. Characteristic of BER and PBER (Rayleigh fading channel, QPSK, aൌ0.3).
Fig.7. Estimated characteristic in case of interference (Rayleigh fading channel, QPSK, aൌ0.3).
Fig.6 ࡼࡾồࡵࡓActual BER PBERࡢ㛵ಀࡣ
Fig.7 ࡛࠶ࡿ㸬Fig.6࠾࠸࡚㸪࣮ࣞࣜࣇ࢙࣮ࢪࣥ
ࢢఏ㏦㊰ࡢሙྜ㸪SNRᑐࡍࡿ PBER ࡢኚࡀ࢞
࢘ࢫఏ㏦㊰ࡢሙྜẚ࡚ᑠࡉ࠸㸬ࡲࡓ㸪ᖸ΅ࡀᏑ ᅾࡍࡿ⎔ቃୗ࡛ࡢActual BERPBERࡢຎࡶᑠ
10-4 10-3 10-2 10-1
10-4 10-3 10-2 10-1
BER
Estimated BER
䢢
䢢
SIR=5dB SIR=10dB SIR=15dB SIR=20dB
0 5 10 15 20 25 30
10-4 10-3 10-2 10-1 100
Average SNR[dB]
BER
䢢
䢢
PBER BER
0 2 4 6 8 10 12
10-5 10-4 10-3 10-2 10-1 100
Average SNR[dB]
BER
䢢
䢢
PBER Actual BER
10-4 10-3 10-2 10-1
10-4 10-3 10-2 10-1
BER
Estimated BER
䢢
䢢
SIR=5dB SIR=10dB SIR=15dB SIR=20dB SIR=30dB SIR=50dB
ࡉ࠸㸬ࡑࡢࡓࡵ㸪Fig.7 ࡛ࡢ᥎ᐃㄗᕪࡣ࢞࢘ࢫఏ㏦
㊰ࡢሙྜẚ࡚ᑠࡉࡃ࡞ࡿ㸬ࡇࢀࡽࡢ⤖ᯝࡼࡾ㸪
࣮ࣞࣜࣇ࢙࣮ࢪࣥࢢఏ㏦㊰࡛ࡢ㏻ಙရ㉁᥎ᐃ
ᑐࡋ࡚ᨃఝࣅࢵࢺㄗࡾࢆ⏝࠸ࡓ㏻ಙရ㉁᥎ᐃἲࡣ
᭷ຠ࡛࠶ࡿࡇࡀࢃࡿ㸬
PUࡢ㏻ಙ࢚ࣜ᥎ᐃἲ
SUࡢ㏦ಙ㟁ຊチᐜ್ࡢᥦ
PUࡢ㏻ಙ࢚ࣜ᥎ᐃἲࡢᥦ
ᮏ◊✲࡛ࡣ௨ୗࡢࡼ࠺࡞ࣔࢹࣝࢆ᳨ウᑐ㇟ࡍ
ࡿ㸬PUࡣᦠᖏ㟁ヰࡢࡼ࠺࡞ࢭࣝᵓᡂࢆࡶࡘ↓⥺ࢩ ࢫࢸ࣒࡛࠶ࡿࡍࡿ㸬ࢥࢢࢽࢸࣈ↓⥺࠾ࡅࡿ
DSA ࠾࠸࡚㸪Fig. 8 ࡢࡼ࠺ PU ࡢ㏦ಙᇶᆅᒁ (PUTX) PUࡢཷಙᒁ (PURX)㸪」ᩘࡢSU (㏦ಙ ᶵ: SUTX㸪ཷಙᶵ: SURX) ➃ᮎ㸪ᑐഃࡢࢭࣝ
⨨ࡍࡿྠ୍࿘Ἴᩘࢆ⏝ࡍࡿᖸ΅ᇶᆅᒁ࡞ࡾ
࠺ࡿPU (PUTX) ࡀᏑᅾࡍࡿ⎔ቃࢆᑐ㇟ࡍࡿ㸬ࡲ
ࡓ㸪SU ࡢཷಙᶵࡣPUࡢ㏻ಙ࢚ࣜෆ㏻ಙ࢚ࣜ
እከᩘ㓄⨨ࡉࢀ࡚࠸ࡿࡍࡿ㸬ࡇࡇ࡛㸪㏻ಙ࢚
ࣜࡢ➃ࢆ࢝ࣂࣞࢵࢪ➃ࡪࡇࡍࡿ㸬
Fig. 8. Targeted system form.
SUࡣPUࡀ㏦ಙࡍࡿಙྕࡢ㏻ಙရ㉁ࢆồࡵ㸪PU ࡢ㏻ಙ࢚ࣜࢆ᥎ᐃࡍࡿ㸬㏻ಙရ㉁ࢆồࡵࡿࡣᮏ ᮶㸪㏦ಙಙྕࡀ᪤▱࡛࠶ࡿᚲせࡀ࠶ࡿ㸬ࢥࢢࢽࢸ
ࣈ↓⥺࠾࠸࡚ࡣ㸪㏦ಙಙྕࡣ᪤▱࡛࡞࠸ࡓࡵ㸪㏻
ಙ࢚ࣜࡢ᥎ᐃ᪉ἲࡋ࡚ࡣ㸪ཷಙ㟁ຊࡽ SNR (Signal to Noise Ratio) ࢆ ồ ࡵ ࡚ ࣅ ࢵ ࢺ ㄗ ࡾ ⋡ (BER: Bit Error Rate) ࢆ᥎ᐃࡍࡿ᪉ἲࡀ⡆༢࡛࠶ࡿ㸬 ࡋࡋ㸪ᖸ΅ࡀ࠶ࡿሙྜࡣᖸ΅ࡶ㏦ಙ㟁ຊぢ࡞ࡋ
࡚ࡋࡲ࠺ࡓࡵ㸪SNR ࡣᮏ᮶ࡼࡾࡶ㧗ࡃ᥎ᐃࡉࢀ࡚
ࡋࡲ࠺㸬ࡑࡇ࡛㸪᪤▱ಙྕࢆᚲせࡏࡎ㏻ಙရ㉁
ࢆ᥎ᐃ࡛ࡁ㸪ᖸ΅ࡢᙳ㡪ࡶᑐᛂ࡛ࡁࡿᨃఝࣅࢵࢺ ㄗࡾࡼࡿ㏻ಙရ㉁᥎ᐃἲࢆ⏝࠸࡚㏻ಙ࢚ࣜࢆ
᥎ᐃࡍࡿ㸬ࡇࢀࡼࡾ㸪࢝ࣂࣞࢵࢪ➃㏆Ꮡᅾࡍ
ࡿ」ᩘࡢSUࡽ㏻ಙ࢚ࣜࢆ᥎ᐃࡍࡿࡇࡀྍ⬟
࡞ࡿ㸬ᮏ◊✲࡛ࡣ㸪ཷಙ㟁ຊࡽSNR (Signal to Noise Ratio) ࢆồࡵ࡚ࣅࢵࢺㄗࡾ⋡ (BER: Bit Error
Rate) ࢆ᥎ᐃࡍࡿ᪉ἲ㸪㏦ಙಙྕࡀ᪤▱࡛࠶ࡿ
ࡋࡓࡁồࡵࡽࢀࡿᐇ㝿ࡢㄗࡾ⋡ࡽ᥎ᐃࡍࡿ
ሙྜࢆẚ㍑ᑐ㇟ࡋ࡚⏝࠸ࡿ㸬
SUࡀPU࠼ࡿᙳ㡪ᑐࡍࡿ᳨ウ ᖸ΅ࡢᏑᅾࡍࡿ⎔ቃ࡛ࡶPUࡢ㏻ಙရ㉁ࡀ᥎ᐃ࡛
ࡁࢀࡤ㸪SUࡀ㏦ಙࡋࡓሙྜࡢᙳ㡪ࢆホ౯ࡍࡿࡇ
ࡶ࡛ࡁࡿ㸬PUࡢ࿘Ἴᩘࡀ୍ⓗ⏝ྍ⬟࡛࠶ࡿ
SU ࡀุ᩿ࡋ㸪SUࡀሗಙྕࢆ㏦ಙࡍࡿ㸪ཷ
ಙഃPUࡶᑡ࡞ࡽࡎᖸ΅ࢆ࠼࡚ࡋࡲ࠺㸬ࡑࡢ ࡓࡵ㸪PUࡢ㏻ಙ࢚ࣜ㞀ᐖࢆ࠼࡞࠸⠊ᅖ࡛㏻
ಙရ㉁ࡢຎチᐜ್ࢆᐃࡵࡿࡇࡀᚲせ࡛࠶ࡿ㸬 ࡋࡋ㸪PUࡽࡢ㟁Ἴࢆࢭࣥࢩࣥࢢࡍࡿ᪉ἲ࡛ࡣ PUࡢ⛬ᗘࡢᙳ㡪ࢆཬࡰࡍࢆ SUࡽࡣุ᩿
࡛ࡁ࡞࠸㸬ࡑࡇ࡛㸪᪤▱ಙྕࢆᚲせࡏࡎ㏻ಙရ
㉁ࢆ᥎ᐃ࡛ࡁࡿᨃఝࣅࢵࢺㄗࡾࡼࡿ㏻ಙရ㉁᥎ ᐃἲࢆ⏝࠸ࢀࡤ㸪࢝ࣂࣞࢵࢪ➃㏆Ꮡᅾࡍࡿཷಙ
ഃSUࡀཷಙഃPUࡢ㏻ಙရ㉁ࢆࣔࢽࢱࣜࣥࢢࡍࡿ
ࡇࡀྍ⬟࡛࠶ࡿࡓࡵ㸪PUࡢ㏻ಙရ㉁ࡢຎᑐ ࡍࡿチᐜ್௨ୗ࡞ࡿࡼ࠺SUࡢ㏦ಙ㟁ຊࢆไᚚ ࡍࡿࡇࡀ࡛ࡁࡿ㸬ᮏ◊✲࡛ࡣチᐜ್ࡑࢀࡒࢀᑐ ࡍࡿ㊥㞳㟁ຊࡢ㛵ಀࢆ᫂ࡽࡍࡿࡇ࡛ᥦ
᪉ᘧࡢ᭷ຠᛶࢆ♧ࡍ㸬
PUࡢ㏻ಙ࢚ࣜ᥎ᐃἲ
SUࡢ㏦ಙ㟁ຊチᐜ್ࡢホ౯ ࢩ࣑࣮ࣗࣞࢩࣙࣥࣔࢹࣝ
PUࡢ㏦ಙಙྕࢆ SUࡀཷಙࡍࡿࡇࡼࡗ࡚㸪 PUࡢ㏻ಙ࢚ࣜࢆ᥎ᐃࡍࡿ㸬ᥦ᪉ᘧࡢ᭷ពᛶࢆ
♧ࡍࡓࡵ㸪ࢩ࣑࣮ࣗࣞࢩࣙࣥࡼࡾホ౯ࡍࡿ㸬Fig. 9
PUSUࡢ㓄⨨ࣔࢹࣝࢆ♧ࡍ㸬 Fig. 9 ࠾࠸࡚㸪
┦ᑐ㊥㞳ࡣᇶᆅᒁࡽ㏻ಙရ㉁ᇶ‽࡞ࡿ㊥㞳 r0
࡛ṇつࡋࡓ㊥㞳࡛࠶ࡿ㸬ᖸ΅ಙྕࡣྠ୍࿘Ἴᩘࡀ
⏝ࡉࢀࡿ㏆᥋ࢭࣝࡽ㏦ಙࡉࢀࡿࡇࢆᐃ
Transmission station
PUTx PU
SU Tx Tx SURx SURx
SURx SURx SURx
SURx SURx
SURx
SURx PURx
Interference station
Communication area Communication area
ࡍࡿ㸬3ࢭࣝ⧞ࡾ㏉ࡋࡢሙྜ࡛ࡣ┦ᑐ㊥㞳ࡣ3࡛࠶
ࡿ㸬ࡇࡢ2ࡘࡢPUTXࡢ㛫SURXࡋ࡚ཷಙⅬ
ࢆ㸪ࡇࡇ࡛ࡣ⡆༢ࡋ㸪㏻ಙ࢚ࣜࡢ᥎ᐃࡀ࡛ࡁࡿ
ࡼ࠺㐺ᙜ࡞㛫㝸 (┦ᑐ㊥㞳ᑐࡋ࡚ 0.2~0.4) ࡛ ᱁Ꮚ≧ከᩘ㓄⨨ࡍࡿ㸬ࢩ࣑࣮ࣗࣞࢩࣙࣥ࠾࠸࡚
ࡣ㸪㊥㞳ఏᦙᦆࡣ⮬⏤✵㛫ఏᦙ⎔ቃ (㊥㞳ఏᦙᦆ ኻ㸸2 ๎) 㝣ୖ⛣ື㏻ಙ⎔ቃ (㊥㞳ఏᦙᦆኻ㸸 3.5๎) ࡢሙྜࢆᐃࡍࡿ㸬ఏ㏦᪉ᘧࡣQPSKኚ ㄪࡢ OFDM᪉ᘧ㸪ఏ㏦㊰ࡣ‽㟼ⓗ࡞࣮ࣞࣜࣇ࢙
࣮ࢪࣥࢢࡍࡿ㸬ࡇࡢࣔࢹࣝୗ࠾࠸࡚㸪ཷಙ㟁ຊ
ࡽ᥎ᐃࡋࡓSNRࢆ⏝࠸࡚ồࡵࡓBER㸪ᨃఝࣅࢵ
ࢺㄗࡾ (a=0.3) ࢆ⏝࠸࡚᥎ᐃࡋࡓ BER㸪ẚ㍑ࡢࡓ
ࡵ㸪㏦ಙሗ᪤▱ࡢ๓ᥦࡢୗ࡛ồࡵࡓActual BER㸪 ࡑࢀࡒࢀࡽ᥎ᐃࡉࢀࡿ㏻ಙ࢚ࣜࢆẚ㍑ࡍࡿ㸬
ࡲࡓ㸪Fig. 9 ࠾࠸࡚㏦ಙⅬࡽ㊥㞳ࡢ␗࡞ࡿཷ
ಙⅬ࡛ࡢSNRࡣ␗࡞ࡿࡓࡵ㸪ᇶ‽࡞ࡿSNRࢆᐃ
⩏ࡍࡿ㊥㞳ࢆSNRᇶ‽㊥㞳ࡪࡇࡍࡿ㸬ࡇ ࡇ࡛ࡣ㸪⡆༢ࡢࡓࡵr0ࢆSNRᇶ‽㊥㞳ࡍࡿ㸬⮬
⏤✵㛫ఏᦙ⎔ቃ㝣ୖ⛣ື㏻ಙ⎔ቃ࠾ࡅࡿ㊥㞳 ఏᦙᦆኻࡣࡑࢀࡒࢀ
ܮሾሿ ൌ ʹͲ ൬ͶɎݎ
ɉ ൰ (1)
ܮሾሿ ൌ ͵ͷ ݎ ʹͲ ൬ͶɎ
ɉ൰ (2)
࡞ࡿ㸬ࡇࡇ࡛㸪r ࡣ㏦ಙⅬࡽࡢ㊥㞳㸪ɉࡣἼ㛗
࡛࠶ࡿ㸬ࡇࢀࡽࡢᘧࢆࢩ࣑࣮ࣗࣞࢩࣙࣥࣔࢹࣝ㐺 ᛂࡍࡿ㸪SNRࡣ㊥㞳ఏᦙᦆࡀ2๎3.5๎ࡢ ሙྜࡑࢀࡒࢀ
ሾሿ ൌ [dB]െ20logቀ
బቁ (3)
ሾሿ ൌ [dB]െ35logቀ
బቁ (4)
࡞ࡿ㸬ࡇࡇ࡛㸪SNR0ࡣ㊥㞳r0࡛ࡢᇶ‽SNR࡛࠶
ࡿ㸬ࡲࡓ㸪ᡤᮃಙྕᖸ΅ಙྕࡢ㟁ຊẚࡣ
ሺሻ ൌ ͳͲ ൬ܲୗ
୍ܲ൰ െ ʹͲ ቀݎ
݀ቁ (5) ሺሻ ൌ ͳͲ ൬ܲୗ
୍ܲ൰ െ ͵ͷ ቀݎ
݀ቁ (6)
࡞ࡿ㸬ࡇࡇ࡛㸪PSࡣ㏦ಙಙྕ㟁ຊ㸪PIࡣᖸ΅ಙ
ྕ㏦ಙ㟁ຊ㸪dࡣཷಙⅬᖸ΅㏦ಙⅬࡢ㊥㞳࡛࠶
ࡿ㸬ࡲࡓ㸪㏦ಙಙྕ㟁ຊᖸ΅ಙྕ㏦ಙ㟁ຊࡢẚࡣ SIR0ࡍࡿ㸬
ࡲࡓ㸪ᚋ㏙࡛♧ࡍ4.3ࡢホ౯࡛ࡣ㸪2ࡘࡢPUTX
ࡢ㛫 SUTXࢆ㓄⨨ࡋ㸪PU ࡢ࢝ࣂࣞࢵࢪ➃Ꮡᅾ ࡍࡿ SURXࢆ⏝࠸࡚㸪㝣ୖ⛣ື㏻ಙ⎔ቃ࠾ࡅࡿ
SUࡀPU࠼ࡿᙳ㡪ᑐࡋ࡚SIR┦ᑐ㊥㞳ࡢ 㛵ಀᛶࡽホ౯ࡍࡿ㸬
Fig. 9. Placement model of PU and SU.
⮬⏤✵㛫ఏᦙࣔࢹ࡛ࣝࡢ㏻ಙ࢚ࣜ᥎ᐃ
3.1ࡢࣔࢹࣝ࠾ࡅࡿ㏻ಙ࢚ࣜ᥎ᐃࢆSIR㸪SNR ࡑࢀࡒࢀࢆኚࡉࡏ࡚⾜࠺㸬࡞࠾㸪ཷಙⅬ㛫㝸ࡣ 0.4ࡋ㸪㏻ಙྍ⬟ࡍࡿBERࡣBER≤0.01ࡍࡿ㸬 Fig. 10 㹼 Fig. 12 ಙྕ㏦ಙ㟁ຊ (PS) ᖸ΅ಙ
ྕ㏦ಙ㟁ຊ (PI) ࡢẚSIR0ࡀࡑࢀࡒࢀ10dB㸪20dB, 30dB㸪ᇶ‽SNR ࡀ20dBࡢሙྜࡢ㏻ಙ࢚ࣜ᥎ᐃ
⤖ᯝࢆ♧ࡍ㸬ᐇ⥺ࡣ Actual BER, ◚⥺ࡣ Estimated BER㸪Ⅼ⥺ࡣཷಙ㟁ຊࡽồࡵࡓBER ࢆ⏝࠸࡚ࡑ
ࢀࡒࢀ㏻ಙ࢚ࣜ᥎ᐃࡋࡓ⤖ᯝ࡛࠶ࡿ㸬ࡲࡓ㸪࣭ࡢ
༳×ࡢ༳ࡣActual BER࠾ࡅࡿ㏻ಙྍ⬟Ⅼ࣭㏻ಙ
ྍ⬟Ⅼࢆࡑࢀࡒࢀ⾲ࡋ࡚࠾ࡾ㸪㏻ಙ࢚ࣜࡣ࣭༳
×༳ࡢ୰㛫Ⅼࢆྲྀࡾ㸪᭱ᑠⓗ᭱㐺㏆ఝࡍࡿ
3ḟࡢከ㡯ᘧ࡛㏆ఝࡋࡓ⥺ࢆ⾲ࡋࡓࡶࡢ࡛࠶ࡿ㸬 Fig. 10 㹼 Fig.12 ࡽࢃࡿࡼ࠺㸪㟁ຊࡽồ
ࡵࡿሙྜ࡛ࡣ㸪ᖸ΅ಙྕࡢࡢ㟁ຊࡽBERࢆ ᥎ᐃࡍࡿࡓࡵ㸪SIRࡀᑠࡉ࠸ᮏ᮶ࡢ㏻ಙ࢚ࣜ
ࡼࡾࡶࡁࡃ࡞ࡗ࡚ࡋࡲ࠺㸬୍᪉㸪Estimated BER
ࡼࡗ࡚᥎ᐃࡉࢀࡓ㏻ಙ࢚ࣜࡣᖸ΅ࡀᏑᅾࡋ࡚
0 1 2 3 4
0 0.5 1 1.5 2 2.5 3 3.5 4
Relative distance
Relative distance
Reference distance of SNR
Transmission point of signal
䠄PUTx䠅 Receiving
point 䠄SURx䠅 Transmission point of
interference signal 䠄PUTx䠅
Fig. 10. Estimation result of communication area (SIR0=10dB).
Fig. 11. Estimation result of communication area (SIR0=20dB).
Fig. 12. Estimation result of communication area (SIR0=30dB).
࠸࡚ࡶActual BERࡼࡗ࡚᥎ᐃࡉࢀࡿ㏻ಙ࢚ࣜ
ࡀࡰ୍⮴ࡍࡿࡇࡀࢃࡿ㸬
ࡲࡓ㸪㏻ಙ࢚ࣜ᥎ᐃࡢ⢭ᗘࡘ࠸࡚᥎ᐃㄗࡾࡢ
ྜࡢほⅬࡽホ౯ࡍࡿ㸬
Fig. 13. Relationship between a real communication area and the estimated communicationarea.
Fig. 13. ࡣ㏻ಙ࢚ࣜ᥎ᐃ࠾ࡅࡿᐇ㝿ࡢ㏻ಙ࢚
ࣜ᥎ᐃࡋࡓ㏻ಙ࢚ࣜࡢ㛵ಀࢆ♧ࡋࡓࡶࡢ࡛
࠶ࡿ㸬A B ࡀ㔜࡞ࡾྜ࠺ሙᡤࡣṇࡋࡃ᥎ᐃࡀ⾜
ࢃࢀࡓ⠊ᅖ࡛࠶ࡿ㸬ഥ ת ࡣᐇ㝿ࡼࡾࡶవศࡁ ࡃ㏻ಙ࢚ࣜࡋุ࡚᩿ࡋ࡚ࡋࡲࡗࡓ⠊ᅖ࡛࠶ࡿ㸬 ࢥࢢࢽࢸࣈ↓⥺࠾ࡅࡿ SU ࡢほⅬࡽゝ࠼ࡤ㸪 SUࡢチᐜ㏦ಙ㟁ຊࢆ㐣ᑠホ౯ࡋ࡚ࡋࡲ࠺ࡇ࡞
ࡿࡀ㸪PU ᝏᙳ㡪ࢆཬࡰࡍࡇࡣ࡞ࡽ࡞࠸㸬
ת ഥ ࡣᐇ㝿ࡼࡾࡶᑠࡉࡃ㏻ಙ࢚ࣜࡋุ࡚᩿
ࡋ࡚ࡋࡲࡗࡓ⠊ᅖ࡛࠶ࡿ㸬ࢥࢢࢽࢸࣈ↓⥺࠾ࡅ
ࡿSUࡢほⅬࡽゝ࠼ࡤ㸪PU ᖸ΅ࢆ࠼࡚ࡋࡲ
࠺ྍ⬟ᛶࡀ⏕ࡌࡿࡇ࡞ࡿ㸬ࡇࡢഥ ת ࡢྜ
ሺഥ ת ሻȀሺ ሻࢆ㐣ホ౯ྜ㸪 ת ഥࡀ㉳ࡇࡿ
ྜሺ ת ഥሻȀሺ ሻࢆ㐣ᑠホ౯ྜࡍࡿ㸬
Fig. 14 ࡣࡇࢀࡽࡢྜࢆ㟁ຊࡽ᥎ᐃࡍࡿሙྜ
Estimated BERࡢሙྜ࡛ホ౯ࡋࡓ⤖ᯝ࡛࠶ࡿ㸬
Fig. 14 ࡽ㸪㟁ຊࢆ⏝࠸ࡓሙྜ࡛ࡣᇶ‽SNRࡀ
࠶ࡿ୍ᐃࡢ್ࡽ㐣ホ౯ྜࡀⴭࡋࡃୖࡀࡗ࡚
࠸ࡿࡇࡀࢃࡿ㸬ࡇࢀࡣ㏦ಙ㟁ຊࡢቑຍకࡗ࡚
㏻ಙ࢚ࣜࡀᣑࡋᖸ΅ᒁ㏆࡙ࡃࡓࡵ㸪ᖸ΅ࡢᙳ 㡪ࡶࡁࡃཷࡅ࡚ࡋࡲ࠺ࡓࡵ࡛࠶ࡿ㸬ࡲࡓ㸪SIR0
ࡀᑠࡉ࠸ุᐃࡢㄗࡾࡀ⏕ࡌࡿ᭱ᑠࡢᇶ‽ SNR ࡣᑠࡉࡃ㸪ㄗࡾࡢྜᑐࡍࡿ್᭱ࡶࡁࡃ࡞ࡗ
࡚࠸ࡿ㸬
0 1 2 3 4
0 0.5 1 1.5 2 2.5 3 3.5 4
Relative distance
Relative distance
䢢
䢢
Actual BER Estimated BER BER(Detected by power)
The cases of Actual BER and Estimated BER is overlaped
0 1 2 3 4
0 0.5 1 1.5 2 2.5 3 3.5 4
Relative distance
Relative distance
䢢
䢢
Actual BER Estimated BER BER(Detected by power)
The cases of Actual BER and Estimated BER is overlaped
Correct estimation communication of
area Underestimation
communication of area
Communication area A by actual BER Estimated communication area B Overestimation communication of
area
0 0.5 1 1.5 2 2.5 3 3.5 4
0 0.5 1 1.5 2 2.5 3 3.5 4
Relative distance
Relative distance
䢢
䢢
Actual BER Estimated BER BER(Detected by power) All of the estimation area is overlaped
Fig. 14. Estimation accuracy of communication area (SIR=20dB).
୍᪉㸪Estimated BERࡽồࡵࡽࢀࡿ㏻ಙ࢚ࣜ
ࡣᐇ㝿ࡢ㏻ಙ࢚ࣜࡢㄗᕪࡣᑠࡉ࠸㸬ࡇࢀࡽࡢ⤖
ᯝࡼࡾ㸪㟁ຊࡽồࡵࡿሙྜ࡛ࡣ㸪㏻ಙ࢚ࣜࡀ㐣
ホ౯ࡉࢀ࡚ࡋࡲ࠺ࡢᑐࡋ࡚㸪Estimated BER
ࡽồࡵࡿሙྜ࡛ࡣ⢭ᗘࡀⰋࡃ㸪SUࡢチᐜ㏦ಙ㟁 ຊ᥎ᐃࡢ≉ᛶྥୖࡀྍ⬟࡛࠶ࡿࡇࡀࢃࡿ㸬
SUࡢ㏦ಙ㟁ຊチᐜ್≉ᛶ
㝣ୖ⛣ື㏻ಙ⎔ቃ࠾࠸࡚㸪㏦ಙᇶᆅᒁᖸ΅ᇶ ᆅᒁࡢ㛫SUTXࢆ㓄⨨ࡍࡿ㸬㏦ಙᇶᆅᒁᖸ΅ᇶ ᆅᒁࡢ㟁ຊࢆ➼㟁ຊࡋ㸪SUTXࡢ㟁ຊ┦ᑐ㊥㞳
ࢆኚࡍࡿ㸬SNR ᇶ‽㊥㞳ࢆ㏻ಙ࢚ࣜࡢ࢝ࣂࣞ
ࢵࢪ➃ࡋࡓࡁ㸪SUTXࡀ㏻ಙ࢚ࣜ㞀ᐖࢆ
࠼࡞࠸⠊ᅖ࡛ࡢ㏦ಙྍ⬟࡞㟁ຊ┦ᑐ㊥㞳ࢆ㸪㏻ಙ
ྍ⬟ࡍࡿBERチᐜ್ࢆタࡅ࡚㸪BER≤P0+∆P ࡋ࡚ホ౯ࡍࡿ㸬ࡇࡇ࡛ P0ࡣチᐜ್ࢆ࠼࡞࠸ࡁ ࡢ㏻ಙྍ⬟࡞BERࡢ್࡛࠶ࡾ㸪∆P0ࡣP0ᑐࡍࡿ
チᐜቑຍྜࢆ࠼ࡿ್࡛࠶ࡿ㸬࡞࠾㏻ಙྍ⬟࡞⠊
ᅖࡣBER≤0.01ࡋ㸪ࡇࡢ್チᐜ್ࢆ࠼ࡿࡶࡢ
ࡍࡿ㸬
3.2࡛㏙ࡓࡼ࠺ SUࡀಙྕࢆ㏦ಙࡍࡿᑡ࡞
ࡽࡎPUᙳ㡪ࢆ࠼࡚ࡋࡲ࠺㸬ᮏホ౯࠾ࡅࡿ
᮲௳ୗ࡛ࡣ㸪Fig. 15 ࡢࡼ࠺PU ࡢ㏻ಙ࢚ࣜࡀ ᑠࡉࡃ࡞ࡗ࡚ࡋࡲ࠺㸬ࡑࡇ࡛チᐜ್ࢆタࡅࡿFig.
16 ࡢࡼ࠺㏻ಙ࢚ࣜࡣಖࡓࢀࡿ㸬࡞࠾㸪Fig. 16
࡛ࡣࡋ࡚ 7 ࢭࣝ⧞ࡾ㏉ࡋ┦ᙜࡢᇶᆅᒁ㛫㊥㞳
࠾ࡅࡿチᐜቑຍྜࢆ 50%ࡋࡓሙྜࢆ♧ࡋ࡚
࠸ࡿ㸬
Fig. 15. Image of the influence that SU gives in the communication area of PU.
Fig. 16. Concept of the measures by the permission level.
ࡇࡢࡼ࠺SUࡀಙྕࢆ㏦ಙࡍࡿ㝿ࡣ㸪㏻ಙရ
㉁ᑐࡋ࡚࠶ࡿ⛬ᗘࡢチᐜࢆタࡅࡿᚲせࡀ࠶ࡾ㸪ࡑ ࡢチᐜ್ࡼࡗ࡚㸪SUࡀ㏦ಙྍ⬟࡞㟁ຊࡢࡁࡉ
ࡶኚࡍࡿ㸬Fig. 17 チᐜቑຍྜᑐࡍࡿ㏻ಙ
ྍ⬟࡞PUSUࡢ㟁ຊẚ㊥㞳ࡢ㛵ಀࢆ♧ࡍ㸬
⤖ᯝࢆFig. 17 ♧ࡍ㸬⦪㍈ࡣPUࡢ㏻ಙရ㉁
ᑐࡍࡿチᐜ್ࢆ‶ࡓࡋ㸪PUࡢ㏻ಙ࢚ࣜ㞀ᐖࢆ
࠼࡞࠸⠊ᅖ࡛ࡢPUࡢ㏦ಙಙྕ㟁ຊSUࡀ㏦ಙ
ྍ⬟࡞᭱㏦ಙ㟁ຊࡢẚ࡛࠶ࡿ㸬ᶓ㍈ࡣSUTXࡢ 㓄⨨ࡍࡿ┦ᑐ㊥㞳࡛࠶ࡿ㸬ࡲࡓ㸪ซࡣࡑࢀࡒࢀチ ᐜቑຍྜࢆ♧ࡋ࡚࠸ࡿ㸬┦ᑐ㊥㞳ࡀᑠࡉ࠸ሙྜ࡛
ࡣ㸪㟁ຊẚࡀࡁࡃ࡞ࡅࢀࡤPUᙳ㡪ࢆ࠼࡚ࡋ
10 12 14 16 18 20 22 24 26
0 20 40 60 80 100
Reference SNR(dB)
Error rate of decision (%)
䢢
Overestimation (Estimated BER) 䢢
Underestimation (Estimated BER) Overestimation (Detected by power) Underestimation (Detected by power)
0 0.5 1 1.5 2 2.5 3
0.5 1 1.5 2 2.5 3 3.5
Reference distance
Reference distance
䢢
䢢 BERd0.01 , SIR0=fdB BERd0.01 , SIR0=20dB
0 0.5 1 1.5 2 2.5 3
0.5 1 1.5 2 2.5 3 3.5
Reference distance
Reference distance
䢢
䢢 BERd0.015 , SIR0=fdB BERd0.015 , SIR0=20dB
ࡲ࠺ࡇࡀࢃࡿࡀ㸪┦ᑐ㊥㞳ࡀࡁ࠸ሙྜ࡛ࡣ㸪 SUࡢ㏦ಙ㟁ຊࢆ࠶ࡿ⛬ᗘࡁࡃࡍࡿࡇࡀྍ⬟࡛
࠶ࡿࡇࡀࢃࡿ㸬ࡲࡓ㸪チᐜ್ࢆ࠼࡞࠸ሙྜ㸪 ᖸ΅ᇶᆅᒁࡽࡢᖸ΅ຍ࠼㸪SUࡽࡢᖸ΅ࡀᙳ 㡪ࡍࡿࡓࡵ㸪㏻ಙ࢚ࣜࢆ☜ಖ࡛ࡁ࡞࠸ࡇࡀࢃ
ࡿ㸬ࡇࡢ⤖ᯝࡽ㸪ᨃఝࣅࢵࢺㄗࡾࢆ⏝࠸ࢀࡤ㸪 SUࡢᖸ΅ࢆไᚚࡋ࡞ࡀࡽ㏻ಙࢆ⾜࠺ࡇࡶྍ⬟
࡛࠶ࡿ࠸࠼ࡿ㸬
Fig. 17. Relationship between upper bound of available SIR and relative distance (Relative distance of the
interference point isҀ21).
⤖ㄽ
ᮏ◊✲࡛ࡣ㸪ࢥࢢࢽࢸࣈ↓⥺࠾ࡅࡿᨃఝࣅࢵ
ࢺㄗࡾࢆ⏝࠸ࡓ㏻ಙရ㉁ࡢ༠ㄪࣔࢽࢱࣜࣥࢢࢆᥦ
ࡋ㸪ࢩ࣑࣮ࣗࣞࢩࣙࣥࡼࡾ㸪ࡑࡢ᭷ពᛶࢆホ౯ ࡋࡓ㸬
ࡑࡢ⤖ᯝ㸪ࢫ࣌ࢡࢺࣝࢭࣥࢩࣥࢢ࡛ࡣ༑ศ᥎ᐃ
࡛ࡁ࡞࠸PUࡢ㏻ಙ࢚ࣜࡢ᥎ᐃࡀྍ⬟࡛࠶ࡿࡇ
ࢆ♧ࡋࡓ㸬ࡲࡓ㸪㟁ຊࢆ⏝࠸࡚BERࢆ᥎ᐃࡍࡿሙ
ྜࡼࡾࡶ⢭ᗘࡀⰋࡃᖸ΅ࡢᙳ㡪ࡶ༑ศ⪃៖࡛ࡁ
ࡿࡇࢆ☜ㄆࡋࡓ㸬ࡉࡽ㸪SUࡢ㏦ಙ㟁ຊチᐜ
್≉ᛶࡽ㸪ᨃఝࣅࢵࢺㄗࡾࢆ⏝࠸ࡓ㏻ಙရ㉁᥎ᐃ ᡭἲࢆ⏝࠸ࢀࡤ㸪SU ࡀPU࠼ࡿᙳ㡪ࡘ࠸࡚
ࡶ⪃៖ࡍࡿࡇࡀ࡛ࡁ㸪PU࠼ࡿᖸ΅ࢆᢚไࡋ ไᚚࡍࡿࡇࡀྍ⬟࡛࠶ࡿ㸬ࡇࢀࡽࡼࡾ㸪ᮏ◊✲ࡢ ᥦἲࢆ⏝࠸ࡿࡇ࡛ࢫ࣌ࢡࢺࣝࢭࣥࢩࣥࢢ࡛ࡣ ᥎ᐃ࡛ࡁ࡞࠸ㄢ㢟ࢆ⿵࠺ࡇࡀ࡛ࡁ㸪SU ࡼࡿ 2 ḟ⏝ࡢ≉ᛶྥୖࢆᅗࡿࡇࡀ࡛ࡁࡿ࠸࠼ࡿ㸬
ᮏ◊✲࡛ࡣSUࢆ᱁Ꮚ≧ከᩘ㓄⨨ࡋࡓࡀ㸪ࡇࢀ
ࡣ⌧ᐇⓗ࡛ࡣ࡞࠸ࡓࡵᚋࡢㄢ㢟࡛࠶ࡿ㸬ࡲࡓ㸪SU ࡢᖸ΅ไᚚᑐࡍࡿ≉ᛶࡸ㸪SUࡀ㏻ಙࢆ⾜࠺㝿 ࡢSUࡢ㏻ಙ࢚ࣜ᥎ᐃࡶ㔜せ࡛࠶ࡾ㸪ᚋࡢㄢ㢟
࡛࠶ࡿ㸬
ཧ⪃ᩥ⊩
1) A. Ghasemi, “Spectrum Sensing in Cognitive Radio Networks: Requirements, Challenges and Design Trade-offs,” IEEE Communications Magazine, 46, 32-39 (2008).
2) R. Chen, J. Park, and Y. T. Hou, “Toward Secure Distributed Spectrum Sensing in Cognitive Radio Networks,” IEEE Communications Magazine, 46, 50-55 (2008).
3) ୕⎼ᨻ୍, 㜰ཱྀၨ, ↓⥺ศᩓࢿࢵࢺ࣮࣡ࢡ, 㸦(♫)㟁 Ꮚሗ㏻ಙᏛ㸪2011㸧㸪pp. 88-99㸬
4) H. Urkowitz, “Energy Detection of Unknown Deterministic Signals,” Proceedings of the IEEE, 55, 523-531 (1967).
5) A. Ghasemi and E.S. Sousa, “Collaborative Spectrum Sensing for Opportunistic Access in Fading Environments,” Proc. DySPAN, 131-136 (2005).
6) E. Visotsky, S. Kuffner, and R. Peterson, “On Collaborative Detection of TV Transmissions in Support of Dynamic Spectrum Sharing,” Proc. DySPAN, 338-345 (2005).
7) S.Mishra, A. Sahai, and R. Brodersen, “Coperative Sensing among Cognitive Radios,” Proc. ICC, 4, 1658-1663 (2006).
8) ᮧᒣ㐩ဢ, ᒾㄔே, ➲ᒸ⚽୍, “ࢥࢢࢽࢸࣈ↓⥺
࠾ࡅࡿᨃఝࣅࢵࢺㄗࡾ᥎ᐃᡭἲࢆ⏝࠸ࡓ㏻ಙ࢚ࣜ
᥎ᐃἲࡢ᳨୍ウ,” 㟁Ꮚሗ㏻ಙᏛࢯࢧ࢚ࢸ
, 294 (2014).
9) ᒾㄔே, Ώ㑔㈗ᚿ, 㧗ಙே, ➲ᒸ⚽୍, “ᨃఝㄗ
ࡾᇶ࡙ࡃࣅࢵࢺㄗࡾ⋡ࡢ᥎ᐃἲ,” 㟁Ꮚሗ㏻ಙ Ꮫ㸪 A࣭P2006-15, 35-40 (2006).
10) ᮧᒣ㐩ဢ, ᒾㄔே, ➲ᒸ⚽୍, “ࢥࢢࢽࢸࣈ↓⥺
࠾ࡅࡿᨃఝࣅࢵࢺㄗࡾ᥎ᐃᡭἲࢆ⏝࠸ࡓ㏻ಙ࢚ࣜ
᥎ᐃἲࡢ᳨୍ウ,” 㟁Ꮚሗ㏻ಙᏛ, SR2014-100, 35-40 (2015).
11) B. Nebendahl, W. Freude, C. Koos, J. Leuthold, M.
Huebner, R. Schmogrow, A. Josten, D. Hillerkuss, S.
Koenig, M. Winter, J. Meiyer, and M. Dreschmann,
“EVM as New Quality Metric for Optical Modulation Analysis,” Proc. Electronics, Communications and Photonics Conference, (2013).
1.4 1.6 1.8 2 2.2 2.4
10 15 20 25 30 35 40 45 50
Relative distance
Upper bound of available SIR (dB)
䢢
䢢
0%10%
20%30%
50%
100%
12) R. A. Shafik, Md. S. Rahman, and A. R. Islam, “On the Extended Relationships among EVM, BER and SNR as Performance Metrics,” Proc. ICECE, 408-411 (2006).
