[Galaxy S Plus I9001 Android Development] omegaRED7:
For what it's worth:

On 3G/HSPA, the logcat for the radio (logcat -b radio) is spammed with signal strength requests each 1-2 seconds (which go unrecognized, for whatever reason, suspect specific Samsung RIL implementation - the unsolicited response code 1009 is for the signal strength - as defined in RILConstants.java) . Maybe this is the reason why the battery drains so quickly on 3G.

12-02 19:27:36.433 E/RIL ( 155): processLine():
12-02 19:27:36.433 E/RIL ( 155): processLine: got a single frame.
12-02 19:27:36.433 E/RIL ( 155): [EVT]:Req(0), RX(1)
12-02 19:27:36.433 E/RIL ( 155): RIL_onMultiClientUnsolicitedResponse:
12-02 19:27:36.433 E/RIL ( 155): unsupported multiclient unsolicited response code 1009
12-02 19:27:38.435 E/RIL ( 155): processLine():
12-02 19:27:38.435 E/RIL ( 155): processLine: got a single frame.
12-02 19:27:38.435 E/RIL ( 155): [EVT]:Req(0), RX(1)
12-02 19:27:38.435 E/RIL ( 155): RIL_onMultiClientUnsolicitedResponse:
12-02 19:27:38.435 E/RIL ( 155): unsupported multiclient unsolicited response code 1009
12-02 19:27:39.436 E/RIL ( 155): processLine():
12-02 19:27:39.436 E/RIL ( 155): processLine: got a single frame.
12-02 19:27:39.436 E/RIL ( 155): [EVT]:Req(0), RX(1)
12-02 19:27:39.436 E/RIL ( 155): RIL_onMultiClientUnsolicitedResponse:
12-02 19:27:39.436 E/RIL ( 155): unsupported multiclient unsolicited response code 1009
12-02 19:27:40.437 E/RIL ( 155): processLine():
12-02 19:27:40.437 E/RIL ( 155): processLine: got a single frame.
12-02 19:27:40.437 E/RIL ( 155): [EVT]:Req(0), RX(1)
12-02 19:27:40.437 E/RIL ( 155): RIL_onMultiClientUnsolicitedResponse:
12-02 19:27:40.437 E/RIL ( 155): unsupported multiclient unsolicited response code 1009
12-02 19:27:41.438 E/RIL ( 155): processLine():
12-02 19:27:41.438 E/RIL ( 155): processLine: got a single frame.
12-02 19:27:41.438 E/RIL ( 155): [EVT]:Req(0), RX(1)
12-02 19:27:41.438 E/RIL ( 155): RIL_onMultiClientUnsolicitedResponse:
12-02 19:27:41.438 E/RIL ( 155): unsupported multiclient unsolicited response code 1009
12-02 19:27:43.430 E/RIL ( 155): processLine():
12-02 19:27:43.430 E/RIL ( 155): processLine: got a single frame.
12-02 19:27:43.430 E/RIL ( 155): [EVT]:Req(0), RX(1)
12-02 19:27:43.430 E/RIL ( 155): RIL_onMultiClientUnsolicitedResponse:
12-02 19:27:43.430 E/RIL ( 155): unsupported multiclient unsolicited response code 1009
12-02 19:27:46.433 E/RIL ( 155): processLine():
12-02 19:27:46.433 E/RIL ( 155): processLine: got a single frame.
12-02 19:27:46.433 E/RIL ( 155): [EVT]:Req(0), RX(1)
12-02 19:27:46.433 E/RIL ( 155): RIL_onMultiClientUnsolicitedResponse:
12-02 19:27:46.433 E/RIL ( 155): unsupported multiclient unsolicited response code 1009
12-02 19:27:47.434 E/RIL ( 155): processLine():
12-02 19:27:47.434 E/RIL ( 155): processLine: got a single frame.
12-02 19:27:47.434 E/RIL ( 155): [EVT]:Req(0), RX(1)
12-02 19:27:47.434 E/RIL ( 155): RIL_onMultiClientUnsolicitedResponse:
12-02 19:27:47.434 E/RIL ( 155): unsupported multiclient unsolicited response code 1009
12-02 19:27:49.436 E/RIL ( 155): processLine():
12-02 19:27:49.436 E/RIL ( 155): processLine: got a single frame.
12-02 19:27:49.436 E/RIL ( 155): [EVT]:Req(0), RX(1)
12-02 19:27:49.436 E/RIL ( 155): RIL_onMultiClientUnsolicitedResponse:
12-02 19:27:49.436 E/RIL ( 155): unsupported multiclient unsolicited response code 1009
12-02 19:27:50.437 E/RIL ( 155): processLine():
12-02 19:27:50.437 E/RIL ( 155): processLine: got a single frame.
12-02 19:27:50.437 E/RIL ( 155): [EVT]:Req(0), RX(1)
12-02 19:27:50.437 E/RIL ( 155): RIL_onMultiClientUnsolicitedResponse:
12-02 19:27:50.437 E/RIL ( 155): unsupported multiclient unsolicited response code 1009
12-02 19:27:53.440 E/RIL ( 155): processLine():
12-02 19:27:53.440 E/RIL ( 155): processLine: got a single frame.
12-02 19:27:53.440 E/RIL ( 155): [EVT]:Req(0), RX(1)
12-02 19:27:53.440 E/RIL ( 155): RIL_onMultiClientUnsolicitedResponse:
12-02 19:27:53.440 E/RIL ( 155): unsupported multiclient unsolicited response code 1009
12-02 19:27:56.442 E/RIL ( 155): processLine():
12-02 19:27:56.442 E/RIL ( 155): processLine: got a single frame.
12-02 19:27:56.442 E/RIL ( 155): [EVT]:Req(0), RX(1)
12-02 19:27:56.442 E/RIL ( 155): RIL_onMultiClientUnsolicitedResponse:
12-02 19:27:56.442 E/RIL ( 155): unsupported multiclient unsolicited response code 1009
12-02 19:27:57.443 E/RIL ( 155): processLine():
12-02 19:27:57.443 E/RIL ( 155): processLine: got a single frame.
12-02 19:27:57.443 E/RIL ( 155): [EVT]:Req(0), RX(1)
12-02 19:27:57.443 E/RIL ( 155): RIL_onMultiClientUnsolicitedResponse:
12-02 19:27:57.443 E/RIL ( 155): unsupported multiclient unsolicited response code 1009
12-02 19:27:58.444 E/RIL ( 155): processLine():
12-02 19:27:58.444 E/RIL ( 155): processLine: got a single frame.
12-02 19:27:58.444 E/RIL ( 155): [EVT]:Req(0), RX(1)
12-02 19:27:58.444 E/RIL ( 155): RIL_onMultiClientUnsolicitedResponse:
12-02 19:27:58.444 E/RIL ( 155): unsupported multiclient unsolicited response code 1009
12-02 19:27:59.445 E/RIL ( 155): processLine():
12-02 19:27:59.445 E/RIL ( 155): processLine: got a single frame.
12-02 19:27:59.445 E/RIL ( 155): [EVT]:Req(0), RX(1)
12-02 19:27:59.445 E/RIL ( 155): RIL_onMultiClientUnsolicitedResponse:
12-02 19:27:59.445 E/RIL ( 155): unsupported multiclient unsolicited response code 1009
12-02 19:28:00.446 E/RIL ( 155): processLine():
12-02 19:28:00.446 E/RIL ( 155): processLine: got a single frame.
12-02 19:28:00.446 E/RIL ( 155): [EVT]:Req(0), RX(1)
12-02 19:28:00.446 E/RIL ( 155): RIL_onMultiClientUnsolicitedResponse:
12-02 19:28:00.446 E/RIL ( 155): unsupported multiclient unsolicited response code 1009
12-02 19:28:01.437 E/RIL ( 155): processLine():
12-02 19:28:01.437 E/RIL ( 155): processLine: got a single frame.
12-02 19:28:01.437 E/RIL ( 155): [EVT]:Req(0), RX(1)
12-02 19:28:01.437 E/RIL ( 155): RIL_onMultiClientUnsolicitedResponse:
12-02 19:28:01.437 E/RIL ( 155): unsupported multiclient unsolicited response code 1009
12-02 19:28:03.449 E/RIL ( 155): processLine():
12-02 19:28:03.449 E/RIL ( 155): processLine: got a single frame.
12-02 19:28:03.449 E/RIL ( 155): [EVT]:Req(0), RX(1)
12-02 19:28:03.449 E/RIL ( 155): RIL_onMultiClientUnsolicitedResponse:
12-02 19:28:03.449 E/RIL ( 155): unsupported multiclient unsolicited response code 1009
12-02 19:28:03.820 D/RILJ ( 610): [1030]> REQUEST_GET_NEIGHBORING_CELL_IDS
12-02 19:28:03.830 E/RIL ( 155): onRequest: GET_NEIGHBORING_CELL_IDS
12-02 19:28:03.830 E/RIL ( 155): CreateRequest(): req(0x196d0), id(75), tok(0x19a00) - FUNC(0x4014c7b1)
12-02 19:28:03.830 E/RIL ( 155): [EVT]:Req(1), RX(0)
12-02 19:28:03.830 E/RIL ( 155): defaultReqHandler()
12-02 19:28:03.830 E/RIL ( 155): RIL_onRequestComplete: tok(0x19a00)
12-02 19:28:03.830 E/RIL ( 155): [RM REQ]: req(0x196d0), tok(0x19a00)
12-02 19:28:03.830 E/RIL ( 155): [EVT]:Req(0), RX(0)
12-02 19:28:03.830 E/RIL ( 155): [EVT]:Req(0), RX(0)
12-02 19:28:03.830 D/RILJ ( 610): Serial: 1030
12-02 19:28:03.830 D/RILJ ( 610): Error: 6
12-02 19:28:03.830 D/RILJ ( 610): [1030]< REQUEST_GET_NEIGHBORING_CELL_IDS error: com.android.internal.telephony.CommandException: REQUEST_NOT_SUPPORTED
12-02 19:28:05.451 E/RIL ( 155): processLine():
12-02 19:28:05.451 E/RIL ( 155): processLine: got a single frame.
12-02 19:28:05.451 E/RIL ( 155): [EVT]:Req(0), RX(1)
12-02 19:28:05.451 E/RIL ( 155): RIL_onMultiClientUnsolicitedResponse:
12-02 19:28:05.451 E/RIL ( 155): unsupported multiclient unsolicited response code 1009
12-02 19:28:06.452 E/RIL ( 155): processLine():
12-02 19:28:06.452 E/RIL ( 155): processLine: got a single frame.
12-02 19:28:06.452 E/RIL ( 155): [EVT]:Req(0), RX(1)
12-02 19:28:06.452 E/RIL ( 155): RIL_onMultiClientUnsolicitedResponse:
12-02 19:28:06.452 E/RIL ( 155): unsupported multiclient unsolicited response code 1009
12-02 19:28:07.453 E/RIL ( 155): processLine():
12-02 19:28:07.453 E/RIL ( 155): processLine: got a single frame.
12-02 19:28:07.453 E/RIL ( 155): [EVT]:Req(0), RX(1)
12-02 19:28:07.453 E/RIL ( 155): RIL_onMultiClientUnsolicitedResponse:
12-02 19:28:07.453 E/RIL ( 155): unsupported multiclient unsolicited response code 1009
12-02 19:28:10.446 E/RIL ( 155): processLine():
12-02 19:28:10.446 E/RIL ( 155): processLine: got a single frame.
12-02 19:28:10.446 E/RIL ( 155): [EVT]:Req(0), RX(1)
12-02 19:28:10.446 E/RIL ( 155): RIL_onMultiClientUnsolicitedResponse:
12-02 19:28:10.446 E/RIL ( 155): unsupported multiclient unsolicited response code 1009
12-02 19:28:11.447 E/RIL ( 155): processLine():
12-02 19:28:11.447 E/RIL ( 155): processLine: got a single frame.
12-02 19:28:11.447 E/RIL ( 155): [EVT]:Req(0), RX(1)
12-02 19:28:11.447 E/RIL ( 155): RIL_onMultiClientUnsolicitedResponse:
12-02 19:28:11.447 E/RIL ( 155): unsupported multiclient unsolicited response code 1009
12-02 19:28:12.448 E/RIL ( 155): processLine():
12-02 19:28:12.448 E/RIL ( 155): processLine: got a single frame.
12-02 19:28:12.448 E/RIL ( 155): [EVT]:Req(0), RX(1)
12-02 19:28:12.448 E/RIL ( 155): RIL_onMultiClientUnsolicitedResponse:
12-02 19:28:12.448 E/RIL ( 155): unsupported multiclient unsolicited response code 1009

This doesn't happen on 2G/EDGE, only occasional error for GET_NEIGHBORING_CELL_IDS. Which in itself is weird, why this request is not supported, but i doubt it's serious.

12-02 19:32:01.882 E/RIL ( 155): onRequest: GET_NEIGHBORING_CELL_IDS
12-02 19:32:01.882 E/RIL ( 155): CreateRequest(): req(0x196d0), id(75), tok(0x19b18) - FUNC(0x4014c7b1)
12-02 19:32:01.882 E/RIL ( 155): [EVT]:Req(1), RX(0)
12-02 19:32:01.882 E/RIL ( 155): defaultReqHandler()
12-02 19:32:01.882 E/RIL ( 155): RIL_onRequestComplete: tok(0x19b18)
12-02 19:32:01.882 E/RIL ( 155): [RM REQ]: req(0x196d0), tok(0x19b18)
12-02 19:32:01.882 E/RIL ( 155): [EVT]:Req(0), RX(0)
12-02 19:32:01.882 E/RIL ( 155): [EVT]:Req(0), RX(0)
12-02 19:32:01.882 D/RILJ ( 610): Serial: 1148
12-02 19:32:01.882 D/RILJ ( 610): Error: 6
12-02 19:32:01.882 D/RILJ ( 610): [1148]< REQUEST_GET_NEIGHBORING_CELL_IDS error: com.android.internal.telephony.CommandException: REQUEST_NOT_SUPPORTED