Mobile terminal, base station and methods therein

1. A method in a base station for managing access to a first contention based channel and a second contention based channel, the method comprising:

encoding system information directly indicating first access request preambles for the first contention based channel, and indirectly indicating second access request preambles for the second contention based channel based on the directly indicated first access request preambles; and

broadcasting the encoded system information to mobile terminals;

wherein the encoding comprises encoding system information that indicates a second available resource of the second contention based channel relative to a first available resource of the second contention based channel;

wherein the system information that indicates the second available resource of the second contention based channel relative to the first available resource of the second contention based channel is encoded in an ordered list that defines common Enhanced-Dedicated Channel (E-DCH) resources;

wherein each E-DCH Resource is defined by a Soffset information element, a Fractional Dedicated Physical Control Channel (F-DPCH) code number information element, and an E-DCH Hybrid Automatic Repeat Request Acknowledgement Indicator Channel (E-HICH) info for common E-DCH information element; and

wherein the position of the second available resource in the ordered list is defined by a default value in the Soffset information element, wherein the default value is a function of the position of the second available resource within the ordered list, a function of a “Soffset” value of a previous first available resource, or a function of the position of the second available resource and an offset value that is a Soffset value of the first available resource.

2. The method of claim 1 , wherein said encoding comprises one of the following:

encoding the system information so that the second access request preambles are derivable as a function of the first access request preambles;

encoding the system information to be included in a System Information Block type 5(SIB5);

encoding the system information to indirectly indicate a preamble scrambling code number of the second access request preambles as a preamble scrambling code of the first access request preambles;

encoding the system information to indirectly indicate a preamble scrambling code number of the second access request preambles as a function of a preamble scrambling code of the first access request preambles;

encoding the system information to indirectly indicate an available sub-channel number of the second access request preambles as being equal to, or the inverse of, an available sub-channel number indicated in an information element denoted Physical Random Access Channel (PRACH) info;

encoding the system information to indicate the first access request preambles in an information element denoted as PRACH info included in a PRACH system information list carried in a SIB5; and

encoding the system information to indicate the first access request preambles for the first contention based channel as available signatures in the information element PRACH info and to indirectly indicate the second access request preambles for the second contention based channel as a function of the first access request preambles in an information element denoted as available signatures in an information element denoted PRACH preamble control parameters for enhanced uplink.

3. The method of claim 1 :

wherein the E-HICH info for common E-DCH information element is defined by a channelization code and a signature sequence;

wherein a default value of the signature sequence is a function of the position of the second available resource within the ordered list, a function of a “Signature Sequence” value of a previous first available resource, or a function of the position of the second available resource and the “Signature Sequence” value of a previous first available resource; and

wherein said encoding comprises encoding the system information to indicate a channelization code of the second available resource as being equal to a channelization code of the first available resource.

4. The method of claim 1 , wherein the second available resource is defined by a value in an information element of a scrambling code of an uplink Dedicated Physical Control Channel, wherein that value is a function of the position of the second available resource within the ordered list of common E-DCH resources, a function of a value in an information element of a scrambling code of an uplink Dedicated Physical Control Channel of a previous first available resource, or a function of the position of the second available resource and an “Uplink DPCH code info for Common E-DCH” value in the information element of a scrambling code of an uplink Dedicated Physical Control Channel of the previous first available resource.

5. A method in a mobile terminal for requesting access to a wireless communication system, the method comprising:

receiving broadcasted system information directly indicating first access request preambles for a first contention based channel, and indirectly indicating second access request preambles for a second contention based channel based on the directly indicated first access request preambles, wherein the received broadcasted system information further indicates a second available resource of the second contention based channel relative to a first available resource of the second contention based channel;

deriving the second access request preambles from the first access request preambles and the second available resource; and

requesting access to the wireless communication system using the second access request preambles or the first access request preambles, and the second or the first available resource to access the second contention based channel or the first contention based channel, respectively, of the wireless communication system;

wherein the second available resource of the second contention based channel relative to the first available resource of the second contention based channel is indicated by the received broadcasted system information in an ordered list that defines common Enhanced-Dedicated Channel (E-DCH) resources;

wherein each E-DCH Resource is defined by a Soffset information element, an Fractional Dedicated Physical Control Channel (F-DPCH) code number information element, and an E-DCH Hybrid Automatic Repeat Request Acknowledgement Indicator Channel (E-HICH) info for common E-DCH information element;

wherein the E-HICH info for common E-DCH information element is defined by a channelization code and a signature sequence; and

wherein a default value of the signature sequence is a function of the position of the second available resource within the ordered list, a function of a “Signature Sequence” value of a previous first available resource, or a function of the position of the second available resource and the “Signature Sequence” value of a previous first available resource.

6. The method of claim 5 , wherein the second access request preambles are derivable as a function of the first access request preambles.

7. The method of claim 5 , wherein the first access request preambles correspond to Physical Random Access Channel (PRACH) preambles comprising a signature sequence, a scrambling code, and a sub-channel, and wherein said deriving comprises:

deriving a preamble scrambling code number of the second access request preambles as a preamble scrambling code of the first access request preambles;

deriving a preamble scrambling code number of the second access request preambles as a function of a preamble scrambling code of the first access request preambles; or

deriving an available sub-channel number of the second access request preambles as being equal to, or as being the inverse of, an available sub-channel number indicated in the information element denoted PRACH info.

8. The method of claim 5 , wherein said deriving comprises:

deriving a channelization code of the second available resource as being equal to a channelization code of the first available resource; or

deriving the second available resource according to a value in an information element of a scrambling code of an uplink Dedicated Physical Control Channel, wherein that value is a function of the position of the second available resource within the ordered list of common E-DCH resources, a function of a value in an information element of a scrambling code of an uplink Dedicated Physical Control Channel of a previous first available resource or a function of the position of the second available resource and an “Uplink DPCH code info for Common E-DCH” value in the information element of a scrambling code of an uplink Dedicated Physical Control Channel of the previous first available resource.

9. A base station for managing access to a first contention based channel and a second contention based channel, the base station comprising:

a processing circuit configured to:

encode system information that directly indicates first access request preambles for the first contention based channel, and indirectly indicates second access request preambles for the second contention based channel based on the directly indicated first access request preambles; and

encode system information that indicates a second available resource of the second contention based channel relative to a first available resource of the second contention based channel; and

a transmitter circuit configured to broadcast the encoded system information to mobile terminals;

wherein the system information that indicates the second available resource of the second contention based channel relative to the first available resource of the second contention based channel is encoded in an ordered list that defines common Enhanced-Dedicated Channel (E-DCH) resources;

wherein each E-DCH Resource is defined by a Soffset information element, a Fractional Dedicated Physical Control Channel (F-DPCH) code number information element, and an E-DCH Hybrid Automatic Repeat Request Acknowledgement Indicator Channel (E-HICH) info for common E-DCH information element; and

wherein the position of the second available resource in the ordered list is defined by a default value in the Soffset information element, wherein the default value is a function of the position of the second available resource within the ordered list, a function of a “Soffset” value of a previous first available resource, or a function of the position of the second available resource and an offset value, which offset value is a Soffset value of the first available resource.

10. The base station of claim 9 , wherein the processing circuit is configured to perform one of the following:

encode the system information so that the second access request preambles are derivable as a function of the first access request preambles;

encode the system information to be included in a System Information Block type 5(SIB5);

encode the system information to indicate a preamble scrambling code number of the second access request preambles as a preamble scrambling code of the first access request preambles;

encode the system information to indicate a preamble scrambling code number of the second access request preambles as a function of the preamble scrambling code of the first access request preambles;

encode the system information to indicate the first access request preambles in an information element denoted as Physical Random Access Channel (PRACH) info included in a PRACH system information list carried in SIB5;

encode the system information to indicate the first access request preambles for the first contention based channel as available signatures in the information element PRACH info and to indirectly indicate the second access request preambles for the second contention based channel as a function of the first access request preambles in an information element denoted as available signatures in an information element denoted PRACH preamble control parameters for enhanced uplink; and

set an available sub-channel number of the second access request preambles to be equal to, or to be the inverse of, an available sub-channel number indicated in the information element denoted PRACH info.

11. The base station of claim 9 :

wherein the E-HICH info for common E-DCH information element is defined by a channelization code and a signature sequence;

wherein a default value of the signature sequence is a function of the position of the second available resource within the ordered list, a function of a “Signature Sequence” value of a previous first available resource, or a function of the position of the second available resource and the “Signature Sequence” value of a previous first available resource; and

wherein the processing circuit is configured to encode the system information to indicate a channelization code of the second available resource as being equal to a channelization code of the first available resource.

12. The base station of claim 9 , wherein the second available resource is defined by a value in an information element of a scrambling code of an uplink Dedicated Physical Control Channel, wherein that value is a function of the position of the second available resource within the ordered list of common E-DCH resources, a function of a value in an information element of a scrambling code of an uplink Dedicated Physical Control Channel of a previous first available resource or a function of the position of the second available resource and an “Uplink DPCH code info for Common E-DCH” value in the information element of a scrambling code of an uplink Dedicated Physical Control Channel of the previous first available resource.

13. A mobile terminal for requesting access to a wireless communication system, the mobile terminal comprising:

a receiver circuit configured to receive broadcasted system information directly indicating first access request preambles for a first contention based channel, and indirectly indicating second access request preambles for a second contention based channel based on the directly indicated first access request preambles, wherein the received broadcasted system information further indicates a second available resource of the second contention based channel relative to a first available resource of the second contention based channel; and

a processing circuit configured to:

derive the second access request preambles from the first access request preambles and the second available resource; and

request access to the wireless communication system using the second access request preambles or the first access request preambles, and the second or the first available resource to access the second contention based channel or the first contention based channel, respectively, of the wireless communication system;

wherein the second available resource of the second contention based channel relative to the first available resource of the second contention based channel is indicated by the received broadcasted system information in an ordered list that defines common Enhanced-Dedicated Channel (E-DCH) resources;

wherein each E-DCH Resource is defined by a Soffset information element, an Fractional Dedicated Physical Control Channel (F-DPCH) code number information element, and an E-DCH Hybrid Automatic Repeat Request Acknowledgement Indicator Channel (E-HICH) info for common E-DCH information element;

wherein the E-HICH info for common E-DCH information element is defined by a channelization code and a signature sequence; and

wherein a default value of the signature sequence is a function of the position of the second available resource within the ordered list, a function of a “Signature Sequence” value of a previous first available resource, or a function of the position of the second available resource and the “Signature Sequence” value of a previous first available resource.

14. The mobile terminal of claim 13 , wherein the processing circuit is configured to derive the second access request preambles as a function of the first access request preambles.

15. The mobile terminal of claim 13 , wherein the first access request preambles correspond to Physical Random Access Channel (PRACH) preambles comprising a signature sequence, a scrambling code, and a sub-channel, and wherein the processing circuit is configured to:

derive a preamble scrambling code number of the second access request preambles as a preamble scrambling code of the first access request preambles;

derive a preamble scrambling code number of the second access request preambles as a function of the preamble scrambling code of the first access request preambles; or

derive an available sub-channel number of the second access request preambles as being equal to, or as being the inverse of, an available sub-channel number indicated in the information element denoted PRACH info.

16. The mobile terminal of claim 13 , wherein the processing circuit is configured to:

derive a channelization code of the second available resource as being equal to a channelization code of the first available resource; or

derive the second available resource according to a value in an information element of a scrambling code of an uplink Dedicated Physical Control Channel, wherein that value is a function of the position of the second available resource within the ordered list of common E-DCH resources, a function of a value in an information element of a scrambling code of an uplink Dedicated Physical Control Channel of a previous first available resource or a function of the position of the second available resource and an “Uplink DPCH code info for Common E-DCH” value in the information element of a scrambling code of an uplink Dedicated Physical Control Channel of the previous first available resource.