MadSci Network: Engineering |
Dear Deepu Paul, You are close regarding the frequency ranges that GSM uses, but in India there are two sets of uplink/downlink frequencies: * 890-915 MHz range for the uplink (I think you confused this and said it was for downlink) fronm the handset to the base station, * 935-960 MHz for the downlink, from the base station to the handset or cellular phone *1710-1785 MHz for the uplink (another frequency band for more capacity) *1805-1880 MHz for the downlink For CDMA in India, the frequencies are: 824 - 849 MHz for the uplink (handset to base station) 869 - 889 (or 894) MHz for the downlink (base station to handset) There also was some discussion about allocating the 1880-1900 MHz frequencies for CDMA in India, but I haven't been able to confirm whether that frequency was actually allocated for CDMA. The confusion about the 889 or 894 might be a spectral allocation issue in India. The CDMA frequencies correspond exactly to the spectral allocations in the USA for CDMA (IS-95 standard), but the U.S.A. downlink is from 869- 894 MHz, the same 25 MHz range as the uplink. The frequency ranges for India were the same, except that the upper limit for India seems to be 889 MHz (see the table in the article from the url listed below and the second source as well), a shortfall of 5 MHz. This might mean that India has some other allocation around 889-894 MHz with which they did not want CDMA to interfere. References: http://www.businessworldindia.com/WebUserArticle.aspx?SectionId=382& ArticleId=941 http://www.businessworldindia.com/WebUserArticle.aspx?SectionId=382& ArticleId=941 Best regards, Eric
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