WCDMA system is said to be interference limited. All cells and users are transmitting on the same frequency and information from individual users is retrieved by coding. The level of interference governs the likelihood of recovering the wanted signal. Minimising the levels of unwanted interference in both the forward and reverse links impacts link quality, cell capacity and cell coverage areas. Nokias RRM is responsible for using the air interface resources optimally and hence maximising cell capacity, cell coverage and ultimately the user link quality for each service.
Two areas in the functional split Cell based functions apply to all the current or even potential connections to a single cell, say of a 3 sector site. Connection based functions apply to every UE currently connected to the cell
Forward link load can be estimated based on throughput. From the equation, the loading is the sum of the bitrates of all currenty active connections divided by the specified maximum throughput for the cell. In the equation Rj is the bitrate of the connection j and N is the total number of connections. Rmax is the maximum thoughput for the cell. Note that in the summation, the bitrates of all the common channels need to be included also. In the reverse link, the load of the cell can be estimated based on the sum of the load factors of the users connected to the cell. In the equation, ‘i’ is the own cell to other cell interference ratio, loadj is the load of user j and N is the number of users.
Forward link load could be estimated by taking the total currently allocated transmit power at the base station PtxTotal and dividing by the maximum transmit power capability of the cell Ptxmax Ie nDL = PtxTotal/Ptxmax In the reverse link, the uplink load factor can be estimated byNul= (Iown+Iother)/PrxTotal. The uplink noise rise can be expressed by the equation NR =Prxtotal/PrxNoise hence PrxNoise/PrxTotal= 1/NR Hence nUL = 1-Prxnoise/Prxtotal = 1-1/NR
Lower area: RT RABS can be admitted as long as they do not inrease Ptx beyond Ptx_target Middle area RT RABS not admitted. NRT RABs can be admitted Higher area: Nothing admitted RT(NC) or NRT if Ptx_Target_BS is exceeded. NRT bit-rates are reduced until Ptx_Total reaches Ptx_targetb
If the IE Establishment Cause of the RRC: RRC Connection Request has any of the values &quot;Emergency call&quot;, &quot;Registration&quot;, &quot;Detach&quot;, &quot;Originating High Priority Signalling&quot;, &quot;Terminating High Priority Signalling&quot;, &quot;Inter-RAT cell reselection&quot;, or &quot;Inter-RAT cell change order&quot;, then the RRC connection request is not rejected either for received wide band power or transmitted power reasons. When the IE Establishment Cause has any of the values &quot;Originating Conversational Call&quot;, &quot;Terminating Conversational Call&quot;, &quot;Originating Streaming Call&quot;, &quot;Terminating Streaming Call&quot;, &quot;Originating Interactive Call&quot;, &quot;Originating Background Call&quot;, &quot;Terminating Interactive Call&quot;, &quot;Terminating Background Call&quot;, &quot;Originating Subscribed traffic Call&quot;, &quot;Originating Low Priority Signalling&quot;, &quot;Terminating Low Priority Signalling&quot;, &quot;Call reestablishment&quot;, or &quot;Terminating - cause unknown&quot;, the RRC connection request is admitted if non-controllable load is below target threshold
Allocates: UL scrambling and spreading DL spreading (but not scrambling as this is fixed per cell by RNP)
Like a lorry with a capacity to carry 1000kg (SF1), it can have 2 * 500 kg packages (SF2), 4 * 250 kg packages(SF3), etc. Draw picture with square that can be divided into sub-squares. Re-arranging the used squares can help to gain capacity.