Abstract: The system includes a plurality of user kits and a head-end kit in bi-directional communication over the electricity network. Its essential characteristics are: carrier by carrier treatment of transmission and reception signals and control of transmission power in each kit. The system makes it possible to reach the maximum the number of users, it maximizes transmission capacity, it admits signals coming from users situated at varying distances both near and far, it avoids the production of overflows, it introduces the maximum average power for the range available to the communication and it minimizes the number of bits necessary for the analog/digital conversion in reception.

Abstract: This process applies to a number of user kits (A, B, . . . X) and a head-end kit (1) communicating over the electricity network (2) using an upstream channel and a downstream channel. In essence, the process comprises accessing by multiple user kits (A, B, . . . X) in the upstream channel and the sending of multiple information frames by the head-end (1) in the downstream channel simultaneously applying OFDMA/TDMA/CDMA multiplexing and dynamically assigning each carrier so as to maximize transmission capacity in both the upstream and downstream channels. In turn, the process allows the adjustment of the quality of service according to the type of information and the user that requires the transmission and the dynamic allocation of bandwidth through constantly calculating the signal-to-noise ratio.

Abstract: The system in this invention is applicable to bi-directional communication over the electricity network between a head-end and a plurality of users, and permits the synchronization in time and frequency of multiple users in a multi-carrier OFDM communication system. It is characterized in that it consists of the generation of synchronization sequences by means of two identical synchronization symbols, periodically transmitted in the downstream, from the head-end to the users to estimate and correct the sampling frequency and simultaneously estimate the moment in which each OFDM symbol commences.

Abstract: The system enables bidirectional communication between a center and a plurality of users via a power line network and is characterized in that low and high speed communication can be established to provide multiple high-quality services to the users. The system comprises a performing network and frequency time-sharing and/or orthogonal frequency-division multiple access (OFDMA).

Abstract: Applicable to two-way communication over the electricity network between a plurality of user equipments (2) and a head-end equipment (1); characterized in that the receptors in the equipment (1, 2) continually monitor communication quality by estimating signal to noise ratio (S/N) in the individual carriers in the upstream and downstream channels. The user equipments monitor the state of the network at each moment in time independent of whether or not the transmission is destination for them. Optimum transmission mode is chosen as a result of this monitoring by means of modifying, packet by packet, the number of bits per carrier, the redundancy introduced by a FEC generator (forward error correction/detection), the FEC code, and/or the transmission mode; so as to achieve optimum sharing of the network in time and frequency at all times and to maximize the transmission capacity of the various user equipments by the network.

Abstract: This process applies to a number of user kits (A, B, . . . X) and a head-end kit (1) communicating over the electricity network (2) by means of an upstream channel and a downstream channel.

Abstract: The system includes a plurality of user kits and a head-end kit in bi-directional communication over the electricity network. Its essential characteristics are: carrier by carrier treatment of transmission and reception signals and control of transmission power in each kit. The system makes it possible to reach the maximum the number of users, it maximizes transmission capacity, it admits signals coming from users situated at varying distances both near and far, it avoids the production of overflows, it introduces the maximum average power for the range available to the communication and it minimizes the number of bits necessary for the analog/digital conversion in reception.

Abstract: The system in this invention is applicable to bi-directional communication over the electricity network between a head-end and a plurality of users, and permits the synchronization in time and frequency of multiple users in a multi-carrier OFDM communication system. It is characterized in that it consists of the generation of synchronisation sequences by means of two identical synchronization symbols, periodically transmitted in the downstream, from the head-end to the users to estimate and correct the sampling frequency and simultaneously estimate the moment in which each OFDM symbol commences.

Abstract: The system enables bidirectional communication between a center and a plurality of users via the electric network and is characterized in that low and high speed communication can be established to provide multiple high-quality services to the users. The system comprises means to perform network and frequency time-sharing and/or orthogonal frequency-division multiple access (OFDMA).