[Nexus S Q&A, Help & Troubleshooting] g33k84:
If i were you I would do the following:

Settings - Wireless & Networks - Mobile Networks - Access Point Names - Delete All the APN's in there, then use one of the DoCoMo ones listed here:

http://code.google.com/p/cyanogenmod/wiki/APNlist

Ensure you have the "Type" section filled with "default,supl" and that you have it selected after SAVING it.

<apn carrier="TA TA DoCoMo" mcc="405" mnc="025" apn="TATA.DOCOMO.INTERNET" type="default,supl" />

<apn carrier="TA TA DoCoMo MMS" mcc="405" mnc="025" apn="TATA.DOCOMO.MMS" mmsc="http://mmsc/" mmsproxy="10.124.26.94" mmsport="8799" type="mms" />

<apn carrier="TA TA DoCoMo" mcc="405" mnc="026" apn="TATA.DOCOMO.INTERNET" type="default,supl" />

<apn carrier="TA TA DoCoMo MMS" mcc="405" mnc="026" apn="TATA.DOCOMO.MMS" mmsc="http://mmsc/" mmsproxy="10.124.26.94" mmsport="8799" type="mms" />

<apn carrier="TA TA DoCoMo" mcc="405" mnc="027" apn="TATA.DOCOMO.INTERNET" type="default,supl" />

<apn carrier="TA TA DoCoMo MMS" mcc="405" mnc="027" apn="TATA.DOCOMO.MMS" mmsc="http://mmsc/" mmsproxy="10.124.26.94" mmsport="8799" type="mms" />

<apn carrier="TA TA DoCoMo" mcc="405" mnc="029" apn="TATA.DOCOMO.INTERNET" type="default,supl" />

<apn carrier="TA TA DoCoMo MMS" mcc="405" mnc="029" apn="TATA.DOCOMO.MMS" mmsc="http://mmsc/" mmsproxy="10.124.26.94" mmsport="8799" type="mms" />

<apn carrier="TA TA DoCoMo" mcc="405" mnc="030" apn="TATA.DOCOMO.INTERNET" type="default,supl" />

<apn carrier="TA TA DoCoMo MMS" mcc="405" mnc="030" apn="TATA.DOCOMO.MMS" mmsc="http://mmsc/" mmsproxy="10.124.26.94" mmsport="8799" type="mms" />

<apn carrier="TA TA DoCoMo" mcc="405" mnc="031" apn="TATA.DOCOMO.INTERNET" type="default,supl" />

<apn carrier="TA TA DoCoMo MMS" mcc="405" mnc="031" apn="TATA.DOCOMO.MMS" mmsc="http://mmsc/" mmsproxy="10.124.26.94" mmsport="8799" type="mms" />

<apn carrier="TA TA DoCoMo" mcc="405" mnc="032" apn="TATA.DOCOMO.INTERNET" type="default,supl" />

<apn carrier="TA TA DoCoMo MMS" mcc="405" mnc="032" apn="TATA.DOCOMO.MMS" mmsc="http://mmsc/" mmsproxy="10.124.26.94" mmsport="8799" type="mms" />

<apn carrier="TA TA DoCoMo" mcc="405" mnc="033" apn="TATA.DOCOMO.INTERNET" type="default,supl" />

<apn carrier="TA TA DoCoMo MMS" mcc="405" mnc="033" apn="TATA.DOCOMO.MMS" mmsc="http://mmsc/" mmsproxy="10.124.26.94" mmsport="8799" type="mms" />

<apn carrier="TA TA DoCoMo" mcc="405" mnc="034" apn="TATA.DOCOMO.INTERNET" type="default,supl" />

<apn carrier="TA TA DoCoMo MMS" mcc="405" mnc="034" apn="TATA.DOCOMO.MMS" mmsc="http://mmsc/" mmsproxy="10.124.26.94" mmsport="8799" type="mms" />

<apn carrier="TA TA DoCoMo" mcc="405" mnc="035" apn="TATA.DOCOMO.INTERNET" type="default,supl" />

<apn carrier="TA TA DoCoMo MMS" mcc="405" mnc="035" apn="TATA.DOCOMO.MMS" mmsc="http://mmsc/" mmsproxy="10.124.26.94" mmsport="8799" type="mms" />

<apn carrier="TA TA DoCoMo" mcc="405" mnc="036" apn="TATA.DOCOMO.INTERNET" type="default,supl" />

<apn carrier="TA TA DoCoMo MMS" mcc="405" mnc="036" apn="TATA.DOCOMO.MMS" mmsc="http://mmsc/" mmsproxy="10.124.26.94" mmsport="8799" type="mms" />

<apn carrier="TA TA DoCoMo" mcc="405" mnc="037" apn="TATA.DOCOMO.INTERNET" type="default,supl" />

<apn carrier="TA TA DoCoMo MMS" mcc="405" mnc="037" apn="TATA.DOCOMO.MMS" mmsc="http://mmsc/" mmsproxy="10.124.26.94" mmsport="8799" type="mms" />

<apn carrier="TA TA DoCoMo" mcc="405" mnc="038" apn="TATA.DOCOMO.INTERNET" type="default,supl" />

<apn carrier="TA TA DoCoMo MMS" mcc="405" mnc="038" apn="TATA.DOCOMO.MMS" mmsc="http://mmsc/" mmsproxy="10.124.26.94" mmsport="8799" type="mms" />

<apn carrier="TA TA DoCoMo" mcc="405" mnc="039" apn="TATA.DOCOMO.INTERNET" type="default,supl" />

<apn carrier="TA TA DoCoMo MMS" mcc="405" mnc="039" apn="TATA.DOCOMO.MMS" mmsc="http://mmsc/" mmsproxy="10.124.26.94" mmsport="8799" type="mms" />

<apn carrier="TA TA DoCoMo" mcc="405" mnc="040" apn="TATA.DOCOMO.INTERNET" type="default,supl" />

<apn carrier="TA TA DoCoMo MMS" mcc="405" mnc="040" apn="TATA.DOCOMO.MMS" mmsc="http://mmsc/" mmsproxy="10.124.26.94" mmsport="8799" type="mms" />

<apn carrier="TA TA DoCoMo" mcc="405" mnc="041" apn="TATA.DOCOMO.INTERNET" type="default,supl" />

<apn carrier="TA TA DoCoMo MMS" mcc="405" mnc="041" apn="TATA.DOCOMO.MMS" mmsc="http://mmsc/" mmsproxy="10.124.26.94" mmsport="8799" type="mms" />

<apn carrier="TA TA DoCoMo" mcc="405" mnc="042" apn="TATA.DOCOMO.INTERNET" type="default,supl" />

<apn carrier="TA TA DoCoMo MMS" mcc="405" mnc="042" apn="TATA.DOCOMO.MMS" mmsc="http://mmsc/" mmsproxy="10.124.26.94" mmsport="8799" type="mms" />

<apn carrier="TA TA DoCoMo" mcc="405" mnc="043" apn="TATA.DOCOMO.INTERNET" type="default,supl" />

<apn carrier="TA TA DoCoMo MMS" mcc="405" mnc="043" apn="TATA.DOCOMO.MMS" mmsc="http://mmsc/" mmsproxy="10.124.26.94" mmsport="8799" type="mms" />

<apn carrier="TA TA DoCoMo" mcc="405" mnc="044" apn="TATA.DOCOMO.INTERNET" type="default,supl" />

<apn carrier="TA TA DoCoMo MMS" mcc="405" mnc="044" apn="TATA.DOCOMO.MMS" mmsc="http://mmsc/" mmsproxy="10.124.26.94" mmsport="8799" type="mms" />

<apn carrier="TA TA DoCoMo" mcc="405" mnc="045" apn="TATA.DOCOMO.INTERNET" type="default,supl" />

<apn carrier="TA TA DoCoMo MMS" mcc="405" mnc="045" apn="TATA.DOCOMO.MMS" mmsc="http://mmsc/" mmsproxy="10.124.26.94" mmsport="8799" type="mms" />

<apn carrier="TA TA DoCoMo" mcc="405" mnc="046" apn="TATA.DOCOMO.INTERNET" type="default,supl" />

<apn carrier="TA TA DoCoMo MMS" mcc="405" mnc="046" apn="TATA.DOCOMO.MMS" mmsc="http://mmsc/" mmsproxy="10.124.26.94" mmsport="8799" type="mms" />

<apn carrier="TA TA DoCoMo" mcc="405" mnc="047" apn="TATA.DOCOMO.INTERNET" type="default,supl" />

<apn carrier="TA TA DoCoMo MMS" mcc="405" mnc="047" apn="TATA.DOCOMO.MMS" mmsc="http://mmsc/" mmsproxy="10.124.26.94" mmsport="8799" type="mms" />