The main degrading factor in indoor wireless optical communication systems for bit rates up to several Mb/s is the shot noise induced by ambient light (sunlight and artificial light produced by incandescent and fluorescent lamps). Due to the directional nature of both signal and ambient light noise, the spatial distribution of the Signal-to-Noise Ratio (SNR) at indoor environments can show large variations. This paper compares techniques that are able to mitigate the effect of such SNR variations: rate-adaptive transmission and angle diversity. In the first technique, the effective data rate is adjusted to the local SNR conditions, by introducing different levels of redundancy. The second technique, explicitly explores the directionality of the SNR by combining signals collected from different observation angles. We address the performance of rate-adaptive transmission and angle diversity techniques and compare them based on experimental results obtained in a typical indoor environment.