Transmit power control scheme for TV white space wireless system
Sang‐Yun Lee, Mee Kyong Kwon, Seung Hun Lee · International Conference on Advanced Communication Technology · 2011
White space means spatially (or temporally) unused spectrum and this can be used on a unlicense basis. Since protecting primary users from harmful interference is the most important issue in unlicensed spectrum access on a secondary basis, regulatory authorities mandate the use of geolocation and DB (database) access capability as interference avoid scheme. The main role of this white space DB is to notify white space device of information required to use spectrum e.g. available channel or maximum transmit power level. Therefore, it is important to devise optimum allocation scheme in order to fully exploit scarce spectrum resources. In this paper, we investigate how DB allocates transmit power in a sense that maximizes total system uplink throughput. There are transmit power constraints in this system, i.e. sum of transmit power of all users are should be controlled so as not to make harmful interference to primary users. With this constraint, we consider optimization problems which maximize total system uplink throughput and show the solution of the optimization problem becomes well known water-filling algorithm.