摘要:
One embodiment of the system and method provides asymmetric adaptive modulation which allows uplink and downlink subframes (304, 302, respectively) of data to be transmitted between a base station (102) and a CPE (104) with different modulation schemes, thus increasing the efficiency of downlink transmissions while maintaining the stability of uplink transmissions. In systems with multiple CPEs, each CPE (104) and base station (102) pair can independently select their uplink and downlink modulation techniques. The system and method are also adaptive in that they adjust the modulation schemes based on, for example, signal to noise ratio measurements or bit error rate measurements.
摘要:
A two-level database structure for use by unlicensed TVBD devices operating in TV white space comprises a central database and local databases. The central database comprises two sub-database: the central licensed database which maintains information about all licensed TV devices and the central unlicensed database which maintains information about unlicensed wireless devices operating in TV spectrum. The local database is created by each TVBD device or TVBD network when it initiates and it stores information related to all transmitters in the local area including location, power transmission levels, operating schedule, sensing results, backup channel information. The local databases communicate with central database to query it about licensed usage of TV spectrum and register with central database. The local databases communicate with each other to exchange information about channel usage, sensing results, transmission patterns and other information that will allow the local databases to negotiate coexistence without central coordinator. The locally implemented negotiation prevents the overloading of the central database.
摘要:
Systems and methods of pre-allocating identifiers to wireless devices for use in requesting resources over a random access channel are described. A wireless communication system includes a random access channel over which wireless devices can anonymously send requests for resources. The base stations receiving and processing the anonymous requests reduces the probability of random access channel collisions and conserves the resources needed to support the anonymous requests by pre-allocating one or more codes to select wireless devices. The wireless devices having the pre-allocated codes can transmit a particular code over the random access channel as a request for resources that uniquely identifies the requestor.
摘要:
A wireless microphone system broadcasts a pilot tone at the designated ATSC pilot position in the TV Band channel being used by the wireless microphone system. The pilot tone is a readily detectable waveform transmitted in the ATSC pilot position. The pilot tone can be generated by any one of: a standalone pilot tone generator; a pilot tone generator incorporated into a wireless microphone receiver; or, a pilot tone generator incorporated into a wireless microphone.