Silicon Investor (SI) -- The First Internet Community

STOCKTALK

We've detected that you're using an ad content blocking browser plug-in or feature. Ads provide a critical source of revenue to the continued operation of Silicon Investor. We ask that you disable ad blocking while on Silicon Investor in the best interests of our community. If you are not using an ad blocker but are still receiving this message, make sure your browser's tracking protection is set to the 'standard' level.

Technology Stocks : Qualcomm Incorporated (QCOM) -- Ignore unavailable to you. Want to Upgrade?

To: S100 who wrote (100384)	6/14/2001 12:15:44 AM
From: S100	Read Replies (1) \| Respond to of 152472

Test says CDMA trials interfering with cell networks Thursday Jun 14 2001 \| Updated 0012 hrs IST 1342 EST -------------------------------------------------------------------------------- Vivek Law MUMBAI JOINT tests carried out by the Wireless Planning Cell and the Telecom Engineering Centre has confirmed that there is strong interference from radio frequencies emanating out of the CDMA-based wireless-in-localloop services which are being tested by the Bharat Sanchar Nigam and MTNL. These signals are disrupting signals of some cellular operators and have hampered their operations. The first set of join tests were concluded on June 7 in Ahmedabad and similar tests have been completed in Maharashtra. Joint testing is expected in Mumbai this week. The joint team has recommended that BSNL should take immediate steps to install filters in their WiLL base stations wherever interference has been reported by cellular operators. This is a temporary solution till such time the WPC comes out with a permanent solution. As a long term solution, it has been recommended that the WPC should reallocate frequency to BSNL for CDMA operations, in a frequency spectrum, away from the part used by GSM operators. “The team has concluded that the radio frequency interference in the GSM allocated band is due to the CDMA-WiLL operation by BSNL. This is on account of allocation of frequency of WiLL with guard band of only 1 Mhz with the GSM band and close proximity of the GSM and CDMA base stations. "The case of interference needs to be addressed on a case-to-case basis," said a source close to the team. The guard band refers to the gap between the parts of the frequency spectrum used by different operators. The WiLL trials are being carried out on the frequency bands 824-844 Mhz and 869-889 Mhz (uplink and downlink respectively), which have been allocated for CDMA-based mobile telephony. The GSM bands on the other hand operate on the 890-915 Mhz and 935-960 Mhz frequency bands. However there is likely to be a delay in installing filters because the TEC will have to specify the type of filters which has to be installed. “The way out is to have filters installed. However, it is learnt that now the TEC will need specify the filters that need to be installed. In the meantime, however, our business will continue to be hit," said a cellular operator. Some operators have also approached the WPC which is believed to have taken the stand that the specifications for the filters to be installed would need to be laid down by the TEC. These operators have also written to the TEC urging it to take necessary action to ensure that there is no further disruption. The operators who have been hit owing to the strong signal interference include Hutchison Max and BPL in Mumbai, BPL in Maharashtra and Fascel in Gujarat. It also includes Tata Cellular in Andhra Pradesh. Operators fear that if the issue is not addressed soon it could snowball into a major problem as currently BSNL and MTNL are only undertaking tests of their proposed services, but once they launch full fledged WiLL services, the interference of the signals could get worse. The decision to carry out joint tests was taken at a high level meeting earlier this month which was attended by senior officials from the WPC and Trai apart from the cellular industry representatives. The telecom equipment vendors for BSNL were also present. In several cases, it has been found that despite transmitting signals within the frequency band applicable to them, the signals on the CDMA-based frequency bands have moved over to the frequency bands being used by the GSM operators. The CDMA signals being stronger, the signals have affected frequencies. The impact has been more on the operators who have got the frequencies adjacent to the 889 Mhz band slot ie from 890-896.2 Mhz (each operator has been given 6.2 Mhz frequency). In the case of Mumbai for instance, MTNL has transmitted signals from 886.59 Mhz, 887.85 Mhz and 889.09 Mhz, which have caused severe interference with Orange’s signals. Call drops have been reported and consequently several cell sites have been badly affected during the period, said sources. In one instance, a prepaid recharge centre could not function for the entire day as it had got jammed with the interfering signals. Even BPL Mobile has been facing some interference even though it lies further away from MTNL on the frequency spectrum. economictimes.com