Study of Multi-cell Interference in a 2-hop OFDMA Virtual Cellular Network (original) (raw)
Related papers
Study of a Multiuser Resource Allocation Scheme for a 2-Hop OFDMA Virtual Cellular Network
In the next generation mobile network, the demand for high data rate transmission will require an increase in the transmission power if the current mobile cellular network architecture is used. Multihop networks are considered to be a key solution to this problem. However, a new resource allocation algorithm is also required for the new network architecture. In this paper, we propose a resource allocation scheme for a parallel relay 2-hop OFDMA virtual cellular network (VCN) which can be applied in a multiuser environment. We evaluate, by computer simu- lation, the ergodic channel capacity of the VCN using the proposed algo- rithm, and compare the results with those of the conventional single hop network (SHN). In addition, we analyze the effect of the location of the relay wireless ports on the ergodic channel capacity of the VCN. We also study the degree of fairness of the VCN, using the proposed scheme, com- pared with that of the SHN. For low transmission power, the simulation results show: a) the VCN can provide a better ergodic channel capacity and a better degree of fairness than the SHN, b) the distance ratio for which the ergodic channel capacity of the VCN is maximal can be found in the interval 0.2∼0.3, c) the ergodic channel capacity of the VCN remains bet- ter than that of the SHN as the number of users increases, and d) as the distance between the relay WPs and the base station increases, the channel capacity of VCN approaches that of the SHN.
Study of the Degree of Fairness for a Parallel Relay 2-hop OFDMA Virtual Cellular Network
With the trend of the evolution of Information and Communication Technology (ICT), high data rate transmission is expected and needed in the next generation mobile network. In order to maintain the same quality of service, the transmission power would need to be increased if the current mobile cellular network architecture is to be considered. To solve this problem, a multi-hop virtual cellular network (VCN) has been proposed. The simulation results of a resource allocation algorithm with interference for a parallel relay 2-hop OFDMA virtual cellular network have shown that the VCN can achieve a better channel capacity than the single hop network for low transmission power. In this paper, using this algorithm, we evaluate the channel capacity of the VCN as the number of users increases, and study the degree of fairness of the VCN compared with that of the conventional single hop network. For low transmission power, the simulation results show: a) the channel capacity of the VCN remains better than that of the single hop network, as the number of users increases, and b) the VCN can achieve a better degree of fairness than the single hop network.
Channel Capacity of Parallel Relaying 2-Hop OFDMA Virtual Cellular Network
2009 IEEE 70th Vehicular Technology Conference Fall, 2009
In the next generation mobile communication systems, high speed data services are expected. However, an unacceptably high transmit power is required. Multi-hop technique can solve this problem. In this paper, we propose a parallel relaying scheme using orthogonal frequency division multiple access (OFDMA), in which the multiple parallel logical routes (one subcarrier is allocated to each link of a logical route) are constructed between a mobile terminal and a base station. Collective construction method, which examines all possible logical routes defined by a physical route and subcarriers to each link along the physical route and selects the best logical route having the maximum channel capacity, requires a prohibitively high complexity. Therefore, we propose a successive construction method. We evaluate the channel capacity of the proposed parallel relaying scheme and compare it with cooperative diversity scheme and also with the conventional single hop network.
Study of an Iterative Resource Allocation Algorithm for a 2-hop OFDMA Virtual Cellular Network
Multi-hop networks can increase the data transmission rate in the next generation mobile network. A new resource allocation algorithm is required for this new type of network architecture. A multi-user resource allocation scheme has been proposed for a 2-hop OFDMA virtual cellular network (VCN). Using that scheme, the VCN can provide better channel capacity than the single hop network (SHN) for low transmission power. However, in the interference dominant transmission power region, the SHN performs better than the VCN. This paper proposes some iterative schemes to increase the channel capacity of the VCN. Using computer simulations, this paper shows that applying those iterative schemes can augment the ergodic channel capacity of the VCN in the interference dominant transmission power region.
Analytical Model of Intercell Interference in Relay Based Cellular OFDMA Networks
Ijca Special Issue on Wireless Communication and Mobile Networks, 2012
In order to improve the coverage and capacity of next generation cellular networks, low cost relays are deployed in the area, where users do not get required Signal to Noise Ratio (SNR) from the base station (BS), especially at the cell edge. The deployment of relays not only reduces the infrastructure cost of setting up new BSs but also supports the rapidly growing number of subscribers. However introduction of Relays introduces additional interferences, which affects the system capacity. In this paper, we analyze this interference in Relay based Orthogonal Frequency Division Multiplexing Access (OFDMA) system. We present an analytical model to characterize the interference experienced by a particular user in a reference cell from all interfering cells irrespective of the position of user. We consider the effect of path loss, shadowing and fading on interference powers from various cells. Then, we determine the Cumulative Distribution Function (CDF) of interference.
2006 IEEE 63rd Vehicular Technology Conference
In order to avoid the large peak transmit power, resulting from the high transmission rates expected for future mobile communication systems, a wireless multi-hop virtual cellular network (VCN) was recently proposed. In VCN, the transmitted signal from a mobile terminal is relayed via multi-hop links to the central port, which is the gateway to the core network. With the use of a routing algorithm based on the total uplink transmit power minimization criterion, the total transmit power of all the multi-hop links between the mobile terminal and the central port can be significantly reduced, in comparison with the present (singlehop) cellular network. Reducing the transmit power per communication contributes to reducing the interference power and hence the system capacity may be enlarged. In this paper, an "on-demand" channel assignment strategy, using the channel segregation dynamic channel allocation (CS-DCA) algorithm, is proposed for multi-hop DS-CDMA VCN. Computer simulation is conducted to evaluate the blocking probability performance and make a comparison between the VCN and the present cellular network.
Dynamic resource allocation in relay-assisted OFDMA cellular system
Transactions on Emerging Telecommunications Technologies, 2011
This study investigates a relay-assisted orthogonal frequency division multiple access cellular system with joint consideration of direct and relaying paths. In this system, a novel implementation adopting full-duplex relaying is proposed for joint relay-destination selection, subcarrier and power allocation. This new implementation can be shown to significantly improve spectrum efficiency as compared with the conventional half-duplex relaying orthogonal frequency division multiple access. In addition, the proposed scheme enables flexible controllability on the tradeoff between system capacity and user fairness.
This paper addresses the Co-Channel Interference (CCI) mitigation in Relay-Assisted (R-A) cellular systems to improve Cell Edge User's (CEU's) performance. Analytical treatments are conducted. The network performance improvement through reducing CCI effects are evaluated using two proposed interference mitigation models. These models denote the R-A sectored Fractional Frequency Reuse (FFR) and R-A Soft Frequency Reuse (SFR). Each model contains two different scenarios for further network performance improvement. The first scenario considers three Relay Stations (RSs) per cell while the other one proposes six RSs in each cell. The best RS placement is proposed. Moreover, closed form expressions for worst cases CEU's SIR, Cell Centre User's (CCU's) SIR and inner radius are implemented. These expressions are used to compare between the considered models using different performance evaluation metrics. The work outcomes enable the system designer to characterize and optimize the multi-cell network performance without a need to execute complex calculations. Also the obtained results contributes to achieve much higher network performance improvement with a lower cost.
Maximizing energy-efficiency in multi-relay OFDMA cellular networks
2013 IEEE Global Communications Conference (GLOBECOM), 2013
This contribution presents a method of obtaining the optimal power and subcarrier allocations that maximize the energy-efficiency (EE) of a multiuser , multi-relay, orthogonal frequency division multiple access (OFDMA) cellular network. Initially, the objective function (OF) is formulated as the ratio of the spectral-efficiency (SE) over the power consumption of the network. This OF is shown to be quasi-concave, thus Dinkelbach's method can be employed for solving it as a series of parameterized concave problems. We characterize the performance of the aforementioned method by comparing the optimal solutions obtained to those found using an exhaustive search. Additionally, we explore the relationship between the achievable SE and EE in the cellular network upon increasing the number of active users. In general, increasing the number of users supported by the system benefits both the SE and EE, and higher SE values may be obtained at the cost of EE, when an increased power may be allocated.
Blocking Probability of a DS-CDMA Multi-Hop Virtual Cellular Network
IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences, 2006
A wireless multi-hop virtual cellular network (VCN) was recently proposed to avoid the large peak transmit power, resulting from the high transmission rates expected for future mobile communication systems. In VCN, calls hop through several links to reach the central port, which is the gateway to the network. With the use of a routing algorithm based on the total uplink transmit power minimization criterion, the total transmit power of all the multi-hop links between the mobile terminal and the central port can be significantly reduced, in comparison with the present (single-hop) cellular network. In this paper, an "on-demand" channel assignment strategy, using the channel segregation dynamic channel allocation (CS-DCA) algorithm, is proposed for multi-hop DS-CDMA VCN. Computer simulation is conducted to evaluate the blocking probability performance and make a comparison between the VCN and the present cellular network.