Abstract

In this thesis, a coexistence of LTE and Wi-Fi is proposed. We assume that
both LTE and Wi-Fi transmit in the same band simultaneously, the Wi-Fi signal,
which is assumed to be the stronger signal, can be decoded first. We can achieve a
good performance of LTE transmission by using a Successive Interference Cancellation
(SIC) scheme. The LTE signal, which is the weaker signal, can be decoded
successfully as though there is no Wi-Fi interference. We implement a Raptor
code for Wi-Fi and a Turbo code for LTE. By adjusting the code rate, the Raptor
codes are adaptive to diferent channel conditions especially with interference.
Meanwhile, the Turbo codes are standardized in LTE transmission.
We propose a new antenna integration design, in which only one antenna is
used. As a result, the space of mobile devices can be saved and the interference
caused by diferent transmissions can be avoided.
Then, we study two scenarios based on diferent channels. Under the first scenario,
a primary user and a secondary user transmit their own signals over the
same AWGN channel. The simulation results indicate that by using a SIC scheme,
an increasing system capacity can be obtained by the secondary transmission, with
no sacrifce of the primary user's performance.
In the second scenario, the LTE and Wi-Fi transmit over a Rayleigh fading
channel simultaneously. A straightforward estimation scheme is adopted to estimate
the Channel State Information (CSI) at the receiver. We discuss two cases
according to the CSI. The first case is that the CSI is available at the receiver.
A novel scheme is proposed to overcome the disadvantages of a slow block fading
channel. In this scheme, we implement an interlever at both the transmitter and
receiver, and therefore utilize the CSI efficiently at the receiver to improve the
system performance. In the second case the CSI is available at both the transmitter
and receiver. An adaptive power control scheme is proposed to adjust the
transmitted power to a desired level, and therefore improve the system.