We introduce a low complexity downlink bit-loading for each subcarrier of a large number of cable modems (CMs) in DOCSIS 3.1. Although different modulations between subcarriers are allowed in DOCSIS 3.1, the number of different bit-loading per subcarrier assignments, called profiles, is limited for computational complexity. Thus, an efficient method of determining the best profile to be used by each CM is needed. The proposed approach is based on a two-step algorithm. In the first step, users are clustered into groups based on their signal-to-noise ratio (SNR) while in the second step, the profile per group (i.e., the bit-loading per sub-carrier) is selected. Two different criteria are investigated for this step. The first one considers the average SNR among the users in the cluster to determine the bit-loading while the second one is more conservative and considers the worst SNR among the users in order to guarantee the targeted BER for all the users in the cluster. Through numerical results, we show the efficiency of the two-step approach and compare the two proposed criteria for bit-loading.
|Publication status||Accepted/In press - 30 Apr 2016|
|Event||Conference: 28th Biennial Symposium on Communications (BSC 2016) - Kelowna, Canada|
Duration: 5 Jun 2016 → 7 Jun 2016
|Conference||Conference: 28th Biennial Symposium on Communications (BSC 2016)|
|Period||5/06/16 → 7/06/16|
- Adaptive Modulation
- data over cable networks
- profile optimization.