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IS-2000 Sync Channel Issue

IS-2000 Sync Channel Issue. The IS95 Sync Channel Message length is increased in IS2000 Release 0 (11 bits) and Release A (14 to 81 bits)

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IS-2000 Sync Channel Issue

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  1. IS-2000 Sync Channel Issue • The IS95 Sync Channel Message length is increased in IS2000 Release 0 (11 bits) and Release A (14 to 81 bits) • Legacy IS95 mobiles from more than one manufacturer (Including Motorola and Nokia) experience problems when Sync Channel Message length is extended beyond 27 octets (IS95 length) • Problems differ depending on manufacturer & message length • There are two issues associated with Motorola IS95 CDMA mobiles (to be summarized in following slides) • All currently shipping product has the issues corrected

  2. Motorola “28 octet” Issue • Experienced when Sync Channel Message exceeds 27 octets (i.e. IS2000 Release 0 and beyond) • Can result in mobile failing to acquire Paging Channel of preferred system (acquires service on “less preferred” system): 4% of time • Can result in delay in acquiring Paging Channel of preferred system: 30% of time • Expected behavior of affected Motorola mobiles • 66% No impact (PCH/BCCH acquired immediately after Sync Channel) • 22% About 4sec delay to acquire PCH/BCCH after acquiring Sync • 8% About 7sec delay to acquire PCH/BCCH after acquiring Sync • 4% PCH/BCCH of most preferred channel not acquired, acquires next channel in PRL

  3. Motorola “32 octet” Issue • Experienced when Sync Channel Message exceeds 31 octets (i.e. IS2000 Release A) • Sync Channel Message exceeds 31 octets ONLY in networks that support Transmit Diversity (TD) and/or 3X channels. • When 31 octets is exceeded, the problem Motorola mobile will reject the Sync Channel Message as too long • Expected behavior of affected Motorola mobiles • 100% Release A CDMA channel never acquired, less preferred IS95 CDMA channel or AMPS channel acquired instead (based on channels in the PRL)

  4. Standards-based Solution • Problem affects a “significant” number of legacy mobiles • Recall would impact smooth evolution to IS2000 • Standards fix desirable, if there are not “significant’ performance trade-offs • Standards-based solution developed jointly between Motorola and Qualcomm, and supported by Nokia, includes 3 “scenarios” • No problem mobiles • “32-octet” problem mobiles AND TD/3X deployed • “28-octet” problem mobiles

  5. Impacts • Proposed standards changes • Add new BCCH Channel List Message to both BCCH and PCH • Allow MS to go directly to Idle State from Traffic Channel, after successful release of traffic channel (and SID, Band Class have not changed) • Other minor changes and bug fixes • In the short-term (where “workarounds” are needed) • Extra “hop” needed to go from Sync to appropriate CDMA Channel • Average worst case delay is 640ms to reach PCH/F-CCCH for pages • 0.7% to 2% increase in PCH/BCCH loading • In the long-term (or where “workarounds” NOT needed) • Standard is improved (Sync acquisition success rate improved, time away from PCH/F-CCCH reduced) • BCCH Channel List Message obsoleted on PCH

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