Apparatus and method for increasing cell capacity through optional signal combining between relay stations in a cellular system using wired relay stations

A system for increasing cell capacity through optional signal combining between Relay Stations (RSs) in a cellular system using wired RSs, the system comprising:

• a Base Station (BS) for receiving a signal of a Mobile Station (MS) from each of the RSs and the MS, and transmitting data to each of the RSs and the MS depending on the received signal;
• a plurality of wired RSs for delivering information on MSs in corresponding coverage to the BS, and performing resource allocation to corresponding MSs, a plurality of wired RSs for delivering information regarding MSs in corresponding coverage areas to the BS, and performing resource allocation to corresponding MSs, wherein a first method of resource allocation is performed on a group of MSs having a carrier/interference ratio (C/I) value greater than a threshold and a second method of resource allocation is performed on a group of MSs having a (C/I) value less than the threshold, by:
• classifying the MSs into two groups according to the C/I value;
• applying signal combining of the RS with the highest C/I value and the RS with the second highest C/I value, if α×Ck′,n′,s1<Ck′,n′,s1,2 is satisfied;
• allocating corresponding subchannel only for the RS with the highest C/I value if α×Ck′,n′,s1<Ck′,n′,s1,2 is not satisfied, wherein
• α is a parameter related to signal combining condition, an MS having a highest C/I value in a corresponding group is defined as k′, an RS with a highest C/I value and an RS with a second highest C/I value are defined as s1 and s2, respectively,
• ck,n,s is defined as a number of transmission bits satisfying a target Bit Error Rate (BER) taking into account a signal level for a subchannel #n that an MS #k has received from an RS #s, and
• a subchannel corresponding to a maximum value of transmittable bits among available subchannels n for k′ and s1 is defined as n′;
• and
• a plurality of MSs for receiving resources allocated from each of the RSs and updating the resource allocation information.

An apparatus for increasing cell capacity through optional signal combining between Relay Stations (RSs) in a cellular system using wired RSs, the apparatus comprising:

• a processor in communication with a memory, the memory including code therein which provides instruction to said processor to cause the processor to execute:
• determining an average Carrier-to-Interference ratio (C/I) value of transmission signals from Mobile Stations (MSs) located inside each coverage area, being fed back from the RSs or the MSs in its corresponding cell;
• classifying the MSs into two groups according to the average C/I value;
• performing resource allocation satisfying a minimum data rate from a corresponding RS, for MSs belonging to a group having a C/I value greater than a preset threshold .GAMMA. among the classified groups;
• performing resource allocation by applying an optional signal combining scheme taking into account a combination of two RSs having a highest C/I value, for MSs belonging to a group having a C/I value below the threshold among the classified groups by;
• applying signal combining of the RS with the highest C/I value and the RS with the second highest C/I value, if α×Ck′,n′,s1<Ck′,n′,s1,2 is satisfied;
• and
• allocating corresponding subchannels only for the RS with the highest C/I value if α×Ck′,n′,s1<Ck′,n′,s1,2 is not satisfied, wherein
• α is a parameter related to signal combining condition, an MS having a highest C/I value in a corresponding group is defined as k′, an RS with a highest C/I value and an RS with a second highest C/I value are defined as s1 and s2, respectuvely, and a subchannel corresponding to a maximum value of transmittable bits among available subchannels n for k′ and s1 is defined as n′;
• Ck n s is defined as a number of transmission bits satisfying a target Bit Error Rate (BER) taking into account a signal level for a subchannel #n that an MS #k has received from an RS #s, and
• allocating all unallocated subchannels of each individual RS in an order of an MS having a high C/I value among MSs of a corresponding RS until there is no more unallocated subchannel of each RS.

A method for resource allocation in a cellular communication system comprising:

• determining an average carrier-to-interference ratio (C/I) value from a plurality of signals received from mobile stations;
• allocating each of the plurality of mobile stations to a selected group, wherein allocation is based on said average carrier-to-interference ratio;
• allocating resources satisfying a minimum data rate from a group of mobile stations having a C/I value greater than a preset threshold;
• allocating resources by applying an optional signal combining scheme considering a combination of two remote stations having a highest C/I value for the mobile stations having a C/I value less than the preset threshold;
• the resource allocation comprising;
• applying signal combining of the RS with the highest C/I value and the RS with the second highest C/I value, if α×Ck′,n′,s1<Ck′,n′,s1,2 is satisfied;
• allocating corresponding subchannel only for the RS with the highest C/I value if α×Ck′,n′,s1<Ck′,n′,s1,2 is not satisfied, wherein
• α is a parameter related to signal combining condition, an MS having a highest C/I value in a corresponding group is defined as k′, an RS with a highest C/I value and an RS with a second highest C/I value are defined as s1 and s2, respectively,
• ck,n,s is defined as a number of transmission bits satisfying a target Bit Error Rate (BER) taking into account a signal level for a subchannel #n that an MS #k has received from an RS #s, and
• a subchannel corresponding to a maximum value of transmittable bits among available subchannels n for k′ and s1 is defined as n′;
• and
• allocating remaining unallocated subchannels of each to mobile stations having a high C/I value among mobile stations.

An apparatus for resource allocation in a cellular communication system comprising:

• a processor in communication with a memory, the memory including code which provides instruction to the processor to cause the processor to execute:
• determining an average carrier-to-interference ratio (C/I) value from a plurality of signals received from mobile stations;
• allocating each of the plurality of mobile stations to a selected group, wherein allocation is based on said average C/I value;
• allocating resources satisfying a minimum data rate from a group of mobile stations having a C/I value greater than a preset threshold;
• allocating resources by applying an optional signal combining scheme considering a combination of two remote stations having a highest C/I value for the mobile stations having a C/I value less than the preset threshold;
• the resource allocation comprising;
• applying signal combining of the RS with the highest C/I value and the RS with the second highest C/I value, if α×Ck′,n′,s1<Ck′,n′,s1,2 is satisfied;
• allocating corresponding subchannel only for the RS with the highest C/I value if α×Ck′,n′,s1<Ck′,n′,s1,2 is not satisfied, wherein
• α is a parameter related to signal combining condition, an MS having a highest C/I value in a corresponding group is defined as k′, an RS with a highest C/I value and an RS with a second highest C/I value are defined s1 and s2, respectively,
• ck,n,s is defined as a number of transmission bits satisfying a target Bit Error Rate (BER) taking into account a signal level for a subchannel #n that an MS #k has received from an RS #s, and
• a subchannel corresponding to a maximum value of transmittable bits among available subchannels n for k′ and s1 is defined as n′;
• and
• allocating remaining unallocated subchannels of each to mobile stations having a high C/I value among mobile stations.