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To: S100 who wrote (13904)	7/17/2001 5:10:07 PM
From: 49thMIMOMander	Read Replies (3) \| Respond to of 34857

S100, if you dig enough you might find out what kind of military system would have either spilled over into the 5Mhz band or didn't have enough receive filtering itself. The 5MHz bands are consecutive for WCMDA in the rest of the world, but in US there are some military,etc stuff in the middle, needing more isolation. Note also that if QCDMA for 3G would have been deployed in Finland it would have disturbed the neighbouring bands so much that one extra band would have been wasted. That is because that 48 tap filter was "future" and "optional", QCOM didn't use any FIR filtering, just blasted the sky full of garbage.. Btw, even your old 56k modem has at least 128 tap filters, only academic idiots with no real experience do 129 tap filters (with MatLab, without any tool to properly optimize them) An ADSL modem has a lot more except if it too is cutting corners. Ilmarinen That is, americans better stay out of spectrum and guardband, out-of-band interference debates, but it is a good way to keep FCC handicapped. That "complex" filter is really fun, hilarious, probably means the poor guy who got the propaganda job has half the taps almost zero, the imaginary ones, ho-ho-ho... Using half the wheels as propellers on a tractor and then complaining the tractor still gets stuck in the mud, didn't make it into a helicopter..

To: S100 who wrote (13904)	7/17/2001 6:02:59 PM
From: Eric L	Read Replies (1) \| Respond to of 34857

<< Well, that sounds good but then how do you explain this? Last I checked, the FCC is not run by ERICY or QCOM >> 3) It has been shown in "IMT-2000 CDMA Chip Rate Selection," T1P1 Harmonization Ad Hoc, 98-024, August 19, 1998, Portland, OR, that even with a difficult-to-realize, complex filter, the 4.096 Mcps rate signal does not meet the FCC out of band emission requirement for a 5 MHz deployment. Well, the Ericsson/DoCoMo WCDMA proposal accepted by ETSI and then by 3GPP in January 1998 was for a 4.096 Mcps rate. Qualcomm was standing fast on 3.6864 and 3GPP on the compromise (originally offerred by Ericsson) of 3.84 Mcps. Maybe the FCC got in the act because Ericsson or 3GPP or GSMNA approached them. I'm guessing Qualcomm did, but it is just a guess. Here is Qualcomm's stance: >> Principle #1 - A single chip rate of 3.6864 Megachips per second should be used for the 5 MHz bandwidth A key requirement for third generation systems is the ability to support IMT-2000 services in spectrum allocations of 5 MHz x 2 (i.e., the network operator has multiples of 5 MHz allocated for the transmit channel and equal 5 MHz multiples allocated for the receive channel). This is true for the D, E, and F band Personal Communications Services (PCS) operators in the U.S. and may also be true in other countries where regulators may partition IMT-2000 spectrum into similar-sized spectrum segments or choose to phase in the allocation of new spectrum. The objective is to fit the wideband CDMA carrier within this allocation, while still allowing for the requisite guard band (a narrow bandwidth between adjacent channels which serves to reduce interference between those adjacent channels) between this carrier and any adjacent uncoordinated carrier. Significant debate has ensued around the choice of the chip rate, which in simple terms, determines the degree of spreading for the CDMA signal. The chip rate, therefore, impacts the carrier spacing and the resultant system capacity. Standard band CDMA TIA/EIA-95 (previously called IS-95) utilizes 1.2288 Megachips per second (Mcps) as the chip rate, resulting in a bandwidth of slightly less than 1.25 MHz. For third generation systems, a chip rate of 3.6864 Mcps has been specified for a variety of reasons. The most obvious is the fact that it fits well into the 5 MHz band allocation, allowing a minimum of 250 kHz as a guard band to be provisioned on either side in order to prevent interference with any adjacent uncoordinated operators. This is not true of the 4.096 Mcps chip rate that has been specified for the competing W-CDMA proposal, which results in a guard band of 0 kHz, making it unacceptable from a spectral emissions perspective. The 3.6864 Mcps value is also 3 x 1.2288, a multiple of the current CDMA chip rate, allowing greater compatibility with the systems now being manufactured and deployed worldwide. The cdma2000 proposal allows two approaches on the forward link, a multi-carrier option and a direct-spread option. A chip rate of 3.6864 Mcps supports both these options and supports a flexible third generation overlay of today's cdmaOne (TIA/EIA-95) systems and, most importantly, equal or greater efficiency in new green field spectrum. The grievances voiced by the North American GSM Alliance on the third generation convergence issue and their opposition to the 3.6864 Mcps chip rate stem from their desire to prevent ease of transition to third generation systems for the cdmaOne operators, and thereby avoid a competitive disadvantage for GSM operators arising from their choice of GSM technology. It is certainly true that use of CDMA in second generation, either initially or following a transition, provides a competitive advantage to use of CDMA in third generation. The power of CDMA should not be weakened in an attempt to somewhat weaken these advantages. The analysis for the 3.6864 Mcps based wideband CDMA system permits the deployment of five wideband CDMA carriers in a 20 MHz x 2 band allocation, with a minimum guard band of 250 kHz on either side of the band. The choice of a 4.096 Mcps chip rate on the other hand allows for only four wideband CDMA carriers in the same 20 MHz allocation, with no guard band at all. In fact, there is significant concern that provisioning four carriers will overlap the edges of the 20 MHz band, potentially causing interference in the adjacent band. In countries where cdmaOne (TIA/EIA-95) deployments exist, the operators could mix the wideband channel with the standard band 1.25 MHz channels, enabling them to provide a greater mix of differentiated voice and data services. In the 15 MHz x 2 band allocation (used in Region 2 and under consideration for new allocations in some countries), choosing 3.6864 Mcps allows the operator to fit three wideband CDMA carriers and additional standard band CDMA carriers. Choosing 4.096 Mcps yields the capability to support at most three wideband carriers. A "compromise" chip rate, 3.84 Mcps, has also been proposed. This change from 3.6864 Mcps is driven by the advocates of competitive disadvantage, and this change would achieve their goal without providing any technical advantage. Thus, it is not a compromise. The 3.6864 Mcps chip rate has true claim for acceptance in the converged standard because it builds on the 100 million or more CDMA subscribers expected by the time IMT-2000 services are offered commercially, currently targeted for 2002. The choice of chip rate has also been incorrectly linked by some opponents of convergence to the issue of Intellectual Property Rights (IPR). This linkage is erroneous and misleading since the selection of the chip rate does not make QUALCOMM's IPR any more or less applicable. Dual chip-rate options have also been discussed to resolve the political issue of chip rate selection. A dual chip rate option unnecessarily complicates the implementation of the handset. Conclusion: QUALCOMM urges the adoption of the 3.6864 Mcps as the single chip rate for the converged standard. << Dr. Jacobs general view Message 5849466 Some Clark Hare comments on all: Message 8520327 On chip rate: Message 8523625 Perry to Clark: Message 8521878 Thas all I know. Chip rate got changed. Maybe the FCC thing prompted Ericsson's compromise offer. I dunno. - Eric -