This paper presents body-to-body radio channel measurements at the 2.45 GHz band, for different body motion scenarios and on-body antenna placements, and both indoor and outdoor environments. Measurement equipment, investigated scenarios and considered environments are described, an initial analysis of results being presented. The mean path loss and the standard deviation depend on the mutual location of transmitting and receiving antennas, type of dynamic scenarios and investigated environments. In general, the lowest mean path loss value (below 57 dB) is obtained for the scenario where two bodies are walking in the same direction along parallel routes and the distance in between bodies equals 1 m; in contrast, the highest value (over 70 dB) is observed for the scenario where both bodies depart from each other being turned back to back. Moreover, the highest standard deviation value (over 13 dB) is obtained for scenarios with antennas mounted on the wrists, which are the most movable parts of the body while walking, and the lowest value (around 2 dB) has been measured for antennas mounted on the head.

This paper presents an off-body channel model for body area networks (BANs) in indoor environments. The proposed model, which is based on both simulations and measurements in a realistic environment, consists of three components: mean path loss, body shadowing, and multipath fading. Seven scenarios in a realistic indoor office environment containing typical scatterers have been measured: five were static (three standing and two sitting) and two dynamic (walk in a fixed place and real walk). The measurement equipment and measurement procedures are described. The mean path loss component is modeled as a log function of distance, the path loss exponent being in the range between 0.4 and 1.6, while a statistical perspective is taken for the other two components, i.e., body shadowing is found to be well modeled by a log normal distribution and multipath fading by Rice or Nakagami-m distributions, depending on body motion characteristics. The correlation between the selected distributions and empirical data is not lower than 0.95, typically being greater than 0.98. The novelty of this model is that it takes the statistical influence of various parameters and features present in BANs into account, such as body influence, placement of the wearable antennas, user orientation in the environment, dynamism of the BAN scenario, and propagation conditions.

This paper presents an off-body fading channel model for Body Area Networks. The proposed model, based on both simulations and measurements at 2.45 GHz in a realistic indoor environment, consists of three components: mean path loss, body shadowing, and multipath fading. The first is modelled as a log function of distance, the path loss exponent being in between 0.4 and 1.6. A statistical perspective is taken for the other two components, i.e., body shadowing is modelled by a Lognormal Distribution, and multipath fading by Rice or Nakagami-m Distributions, depending on body motion characteristics. The correlation between selected distributions and empirical data is always higher than 0.95, typically being greater than 0.98. This model takes the statistical influence of various parameters and features present in BANs into account.

Users of triple-play systems expect to be able to use their services on different locations. That opens an issue of extending security to include mobile triple-play users. Mobile users need to authenticate to the system and vice-versa. Users expect confidentiality of their communications. Content providers request copyrights to be respected. Protocols for session control, SIP. and media transfer, RTP, have their secured versions, SIPS and RTSP. That solution would require multiple protocols and keys and would be a burden on users and system administrators. This paper proposes an architecture that uses IMS to provide services and VPN to secure them. IMS provides convenience of user mobility. VPN provides authentication, confidentiality and integrity. Additional security provided by VPN does not translate to additional work for users, It is completely transparent for them. Proposed design is implemented and tested. IMS with different services was available, through VPN, to mobile users connected to the Internet with different devices and connections. The testing confirmed security and usability for mobile users.

In order to satisfy constantly increasing user demands, in process of transition towards LTE (Long Term Evolution) mobile networks of 4th generation, for 3G UMTS networks potential solution is exploitation of multi-antenna MIMO (Multiple Input Multiple Output) systems, which provide increase in both capacity and reliability. This paper puts an effort to provide a link between link-level and system-level gains introduced by multi-antenna techniques in UMTS systems. Coverage, capacity and achievable data rates are evaluated and presented for Alamouti scheme, TxAA and D-TxAA. Radio mobile planning tool is used for illustration of coverage improvement achieved by implementation of several multi-antenna techniques. Considering system-level gains, it is seen that implementation of MIMO techniques yields larger service area and/or increase in capacity and available data rates maintaining the same bandwidth. Results presented in this paper help making a clear picture of achievable gains, employment costs and answering the question: Should mobile operators invest in upgrading their 3G networks with MIMO techniques and is that investment justified, considering achievable improvements.