2,627 research outputs found
A Framework for Uplink Intercell Interference Modeling with Channel-Based Scheduling
This paper presents a novel framework for modeling the uplink intercell
interference (ICI) in a multiuser cellular network. The proposed framework
assists in quantifying the impact of various fading channel models and
state-of-the-art scheduling schemes on the uplink ICI. Firstly, we derive a
semianalytical expression for the distribution of the location of the scheduled
user in a given cell considering a wide range of scheduling schemes. Based on
this, we derive the distribution and moment generating function (MGF) of the
uplink ICI considering a single interfering cell. Consequently, we determine
the MGF of the cumulative ICI observed from all interfering cells and derive
explicit MGF expressions for three typical fading models. Finally, we utilize
the obtained expressions to evaluate important network performance metrics such
as the outage probability, ergodic capacity, and average fairness numerically.
Monte-Carlo simulation results are provided to demonstrate the efficacy of the
derived analytical expressions.Comment: IEEE Transactions on Wireless Communications, 2013. arXiv admin note:
substantial text overlap with arXiv:1206.229
OTFS-NOMA: An Efficient Approach for Exploiting Heterogenous User Mobility Profiles
This paper considers a challenging communication scenario, in which users
have heterogenous mobility profiles, e.g., some users are moving at high speeds
and some users are static. A new non-orthogonal multiple-access (NOMA)
transmission protocol that incorporates orthogonal time frequency space (OTFS)
modulation is proposed. Thereby, users with different mobility profiles are
grouped together for the implementation of NOMA. The proposed OTFS-NOMA
protocol is shown to be applicable to both uplink and downlink transmission,
where sophisticated transmit and receive strategies are developed to remove
inter-symbol interference and harvest both multi-path and multi-user diversity.
Analytical results demonstrate that both the high-mobility and low-mobility
users benefit from the application of OTFS-NOMA. In particular, the use of NOMA
allows the spreading of the high-mobility users' signals over a large amount of
time-frequency resources, which enhances the OTFS resolution and improves the
detection reliability. In addition, OTFS-NOMA ensures that low-mobility users
have access to bandwidth resources which in conventional OTFS-orthogonal
multiple access (OTFS-NOMA) would be solely occupied by the high-mobility
users. Thus, OTFS-NOMA improves the spectral efficiency and reduces latency
A General MIMO Framework for NOMA Downlink and Uplink Transmission Based on Signal Alignment
The application of multiple-input multiple-output (MIMO) techniques to
non-orthogonal multiple access (NOMA) systems is important to enhance the
performance gains of NOMA. In this paper, a novel MIMO-NOMA framework for
downlink and uplink transmission is proposed by applying the concept of signal
alignment. By using stochastic geometry, closed-form analytical results are
developed to facilitate the performance evaluation of the proposed framework
for randomly deployed users and interferers. The impact of different power
allocation strategies, such as fixed power allocation and cognitive radio
inspired power allocation, on the performance of MIMO-NOMA is also
investigated. Computer simulation results are provided to demonstrate the
performance of the proposed framework and the accuracy of the developed
analytical results
Performance of Optimum Combining in a Poisson Field of Interferers and Rayleigh Fading Channels
This paper studies the performance of antenna array processing in distributed
multiple access networks without power control. The interference is represented
as a Poisson point process. Desired and interfering signals are subject to both
path-loss fading (with an exponent greater than 2) and to independent Rayleigh
fading. Using these assumptions, we derive the exact closed form expression for
the cumulative distribution function of the output
signal-to-interference-plus-noise ratio when optimum combining is applied. This
results in a pertinent measure of the network performance in terms of the
outage probability, which in turn provides insights into the network capacity
gain that could be achieved with antenna array processing. We present and
discuss examples of applications, as well as some numerical results.Comment: Submitted to IEEE Trans. on Wireless Communication (Jan. 2009
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