A method is known from document WO 2005/011154 which sets out to prevent a reduction in data transmission rate towards users in a 1xEvDO system. However this method solely concerns connection problems in a base station and proposes the management of user-associated connections to avoid overloading some of these connections.
In known cellular mobile telephony systems of CDMA type using several carriers, there is no method for optimising the capacity of the network, in particular by limiting accumulated transmission powers towards user mobile terminals so as to adapt operationally to the traffic to be handled. Existing solutions are limited to power planning within each cell, which is unsatisfactory from an operational viewpoint since load disparities exist within one same cell.
One major disadvantage of known methods is that some areas within a cell do not provide radio access of quality on account of a signal-to-noise ratio (SNR) that is too low. In these areas, data transmission rate is therefore very low (for a determined bandwidth) or else the use of a very broad channel is required to ensure a sufficient bit rate.
By way of illustration, the power ratio C/I between the carrier signal and the interferer signal may vary from 0 to more than 15 dB depending on whether the client using the mobile terminal is on the edge of a cell or nearer the transmitter. To improve network capacity, current solutions consist of adding new carriers on additional frequencies, the channelling of technologies of CDMA type being fixed (channel width of 1.25 MHz for CDMA 2000, 5 MHz for UMTS.
There is therefore a need to find a method more adapted to actual site conditions with which it is possible to efficiently configure the network so as to optimise the global capacity of the network and the data rate for users located in those cell areas that are least well served.
USPTO Backgrounds
USPTO Backgrounds